SEEMANN JULIA (DE)
HUWER THOMAS (DE)
HANFT SEBASTIAN (DE)
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| WO2021160701A1 | 2021-08-19 | |||
| WO2022049307A1 | 2022-03-10 |
| EP3815540A1 | 2021-05-05 | |||
| EP3261455B1 | 2022-01-26 | |||
| EP22193439A | 2022-09-01 | |||
| EP22200973A | 2022-10-11 | |||
| EP22200974A | 2022-10-11 | |||
| EP23152846A | 2023-01-23 | |||
| EP23152845A | 2023-01-23 | |||
| US20200196648A1 | 2020-06-25 | |||
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| KR20160062349A | 2016-06-02 | |||
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| US20180281263A1 | 2018-10-04 | |||
| US20200001502A1 | 2020-01-02 | |||
| EP0919127A1 | 1999-06-02 |
| Patent claims: 1. A process for the preparation of a particulate allulose composition, the process comprising the steps of (a) providing an aqueous allulose syrup comprising allulose essentially in dissolved form at a purity of at least 90.0 wt-%, relative to the dry solids content of the allulose symp; (b) evaporating water from the allulose syrup at a first temperature thereby obtaining an concentrated composition having a dry solids content of at least 90.0 wt-%, relative to the total weight of the concentrated composition; (c) optionally, adding seed crystals of allulose to the concentrated composition thereby obtaining a seeded suspension; (d) optionally, adjusting the temperature of the seeded suspension to a second temperature differing from the first temperature; (e) optionally, introducing mechanical energy into the seeded suspension thereby obtaining a viscous composition; (f) optionally, forming the viscous composition into a film; (g) allowing the concentrated composition, seeded suspension or viscous composition to solidify thereby obtaining a solidified allulose composition; and (h) purifying the solidified allulose composition by (i) washing the solidified allulose composition with a solvent; or (ii) comminuting the solidified allulose composition and washing the comminuted allulose composition with a solvent; thereby obtaining the particulate allulose composition. 2. The process according to claim 1, wherein the aqueous allulose syrup provided in step (a) additionally comprises fructose. 3. The process according to claim 2, wherein the content of fructose is at most 9.0 wt.-%, preferably at most 8.0 wt-%, more preferably at most 7.0 wt.-%, still more preferably at most 6.0 wt-%, yet more preferably at most 5.0 wt-%, even preferably at most 4.5 wt-%, most preferably at most 4.0 wt-%, and in particular at most 3.5 wt-%, relative to the dry solids content of the allulose symp. 4. The process according to any of the preceding claims, wherein the aqueous allulose syrup provided in step (a) additionally comprises glucose. 5. The process according to claim 4, wherein the content of glucose is at most 7.0 wt-%, preferably at most 6.0 wt-%, more preferably at most 5.0 wt-%, still more preferably at most 4.0 wt-%, yet more preferably at most 3.0 wt-%, even preferably at most 2.5 wt-%, most preferably at most 2.3 wt-%, and in particular at most 2.0 wt-%, relative to the dry solids content of the allulose symp. The process according to any of the preceding claims, wherein the aqueous allulose syrup provided in step (a) additionally comprises sucrose. The process according to claim 6, wherein the content of sucrose is at most 3.0 wt.-%, preferably at most 2.5 wt.-%, more preferably at most 2.0 wt.-%, still more preferably at most 1.8 wt-%, yet more preferably at most 1.5 wt.-%, even preferably at most 1.3 wt.-%, most preferably at most 1.0 wt.-%, and in particular at most 0.8 wt.-%, relative to the dry solids content of the allulose syrup. The process according to any of the preceding claims, wherein the aqueous allulose syrup provided in step (a) additionally comprises hydroxymethyl furfural (HMF). The process according to claim 8, wherein the content of hydroxymethyl furfural (HMF) is at most 1000 ppm, preferably at most 500 ppm, more preferably at most 200 ppm, relative to the dry solids content of the allulose syrup. The process according to any of the preceding claims, wherein the aqueous allulose syrup provided in step (a) essentially consists of allulose, water, fructose and optionally hydroxymethyl furfural (HMF). The process according to any of the preceding claims, wherein the purity of the allulose comprised in the aqueous allulose syrup provided in step (a) is at least 91.0 wt-%, preferably at least 92.0 wt-%, more preferably at least 93.0 wt-%, still more preferably at least 94.0 wt-%, yet more preferably at least 95.0 wt-%, even more preferably at least 95.5 wt-%, most preferably at least 96.0 wt-%, and in particular at least 96.5 wt-%, relative to the dry solids content of the allulose symp. The process according to any of the preceding claims, wherein the pH value of the aqueous allulose syrup provided in step (a) is at least 4.0, more preferably at least 4.5, still more preferably at least 4.7, yet more preferably at least 5.0, even more preferably at least 5.2, most preferably at least 5.5, and in particular at least 5.7. The process according to any of the preceding claims, wherein the pH value of the aqueous allulose symp provided in step (a) is at least 3.5, preferably at least 4.0, preferably at least 4.5, preferably at least 4.6, preferably at least 4.7, preferably at least 4.8, preferably at least 4.9, preferably at least 5.0, preferably at least 5.1, preferably at least 5.2, preferably at least 5.3, preferably at least 5.4, preferably at least 5.5, preferably at least 5.6, preferably at least 5.7, preferably at least 5.8, preferably at least 5.9, preferably at least 6.0. The process according to any of the preceding claims, wherein the pH value of the aqueous allulose syrup provided in step (a) is within the range of 6.0±4.0, preferably 6.0±3.5, more preferably 6.0±3.0, still more preferably 6.0±2.5, yet more preferably 6.0±2.0, even more preferably 6.0±1.5, most preferably 6.0±1.0, and in particular 6.0±0.5. The process according to any of claims 1 to 13, wherein the pH value of the aqueous allulose syrup provided in step (a) is within the range of 7.0±4.0, preferably 7.0±3.5, more preferably 7.0±3.0, still more preferably 7.0±2.5, yet more preferably 7.0±2.0, even more preferably 7.0±1.5, most preferably 7.0±1.0, and in particular 7.0±0.5. The process according to any of claims 1 to 13, wherein the pH value of the aqueous allulose symp provided in step (a) is within the range of 8.0±4.0, preferably 8.0±3.5, more preferably 8.0±3.0, still more preferably 8.0±2.5, yet more preferably 8.0±2.0, even more preferably 8.0±1.5, most preferably 8.0±1.0, and in particular 8.0±0.5. The process according to any of the preceding claims, wherein the concentrated composition obtained in step (b) has a dry solids content of at least 91.0 wt-%, preferably at least 92.0 wt-%, more preferably at least 93.0 wt-%, still more preferably at least 94.0 wt-%, yet more preferably at least 94.5 wt-%, even more preferably at least 95.0 wt-%, most preferably at least 95.5 wt-%, and in particular at least 96.0 wt- %, relative to the total weight of the concentrated composition. The process according to any of the preceding claims, wherein the concentrated composition obtained in step (b) has a dry solids content of at most 99.5 wt-%, preferably at most 99.0 wt-%, more preferably at most 98.5 wt-%, still more preferably at most 98.0 wt-%, yet more preferably at most 97.5 wt-%, even more preferably at most 97.0 wt-%, most preferably at most 96.5 wt-%, and in particular at most 96 wt- %, relative to the total weight of the concentrated composition. The process according to any of the preceding claims, wherein the concentrated composition obtained in step (b) has a dry solids content within the range of 96.0±2.0 wt-%, preferably 96.0±1.5 wt-%, more preferably 95.5 to 97.0 wt-%, still more preferably 96.0±1.0 wt-%, yet more preferably 96.0±0.5 wt-%, even more preferably 96.0 to 96.5 wt-%, relative to the total weight of the concentrated composition. The process according to any of the preceding claims, wherein in step (b) the first temperature is at least 35 °C; preferably at least 40 °C, more preferably at least 43 °C, still more preferably at least 46 °C, yet more preferably at least 49 °C, even more preferably at least 52 °C, most preferably at least 55 °C, and in particular at least 58 °C. The process according to any of the preceding claims, wherein in step (b) the first temperature is at most 70 °C; preferably at most 65 °C, more preferably at most 60 °C, still more preferably at most 57 °C, yet more preferably at most 54 °C, even more preferably at most 51 °C, most preferably at most 48 °C, and in particular at most 45 °C. The process according to any of the preceding claims, wherein in step (b) the first temperature is within the range of 53±20 °C; preferably 53±15 °C, more preferably 53±12 °C, still more preferably 53±10 °C, yet more preferably 53±8.0 °C, even more preferably 53±6.0 °C, most preferably 53±4.0 °C, and in particular 53±3.0 °C. The process according to any of the preceding claims, wherein in step (b) the water is evaporated from the allulose syrup under reduced pressure. The process according to any of the preceding claims, wherein step (b) involves heating the allulose syrup thereby producing a gas phase containing water, wherein the gas phase has a gas pressure that is maintained below atmospheric pressure. The process according to claim 24, wherein the gas pressure in step (b) is at most 800 mbar; preferably at most 750 mbar, preferably at most 700 mbar, preferably at most 650 mbar, preferably at most 600 mbar, preferably at most 550 mbar, preferably at most 500 mbar, preferably at most 450 mbar, preferably at most 400 mbar, preferably at most 350 mbar, preferably at most 300 mbar, preferably at most 250 mbar, preferably at most 200 mbar, preferably at most 150 mbar, preferably at most 100 mbar, preferably at most 90 mbar, preferably at most 80 mbar, preferably at most 70 mbar, preferably at most 60 mbar, preferably at most 50 mbar, preferably at most 40 mbar, preferably at most 30 mbar, preferably at most 20 mbar, preferably at most 10 mbar. The process according to claim 24 or 25, wherein the gas pressure in step (b) is at least 40 mbar; preferably at least 60 mbar, more preferably at least 80 mbar, still more preferably at least 100 mbar, yet more preferably at least 120 mbar, even more preferably at least 140 mbar, most preferably at least 160 mbar, and in particular at least 180 mbar. The process according to any of claims 24 to 26, wherein the gas pressure in step (b) is within the range of 450±400 mbar; preferably 400±350 mbar, more preferably 350±300 mbar, still more preferably 300±250 mbar, yet more preferably 250±200 mbar, even more preferably 200±150 mbar, most 150±100 mbar, and in particular 125±75 mbar. The process according to any of the preceding claims, wherein the pH value of the allulose syrup resulting from the evaporation of water in step (b) is adjusted by the addition of an acidic additive or by the addition of a basic additive or by treatment with an ion exchange resin. The process according to any of the preceding claims, wherein the pH value of the allulose syrup resulting from the evaporation of water in step (b) is adjusted to a pH value of at least 3.5, preferably at least 4.0, preferably at least 4.5, preferably at least 4.6, preferably at least 4.7, preferably at least 4.8, preferably at least 4.9, preferably at least 5.0, preferably at least 5.1, preferably at least 5.2, preferably at least 5.3, preferably at least 5.4, preferably at least 5.5, preferably at least 5.6, preferably at least 5.7, preferably at least 5.8, preferably at least 5.9, preferably at least 6.0. The process according to any of the preceding claims, wherein the pH value of the allulose syrup resulting from the evaporation of water in step (b) is adjusted to a pH value of at least 4.0, more preferably at least 4.5, still more preferably at least 4.7, yet more preferably at least 5.0, even more preferably at least 5.2, most preferably at least 5.5, and in particular at least 5.7. The process according to any of the preceding claims, wherein in step (c) the aqueous allulose syrup to which seed crystals are added has a pH of at least 4.0, more preferably at least 4.5, still more preferably at least 4.7, yet more preferably at least 5.0, even more preferably at least 5.2, most preferably at least 5.5, and in particular at least 5.7. The process according to any of the preceding claims, wherein in step (c) the amount of seed crystals added to the concentrated composition is at least 3.0 wt-%; preferably at least 4.0 wt-%, more preferably at least 5.0 wt-%, still more preferably at least 6.0 wt-%, yet more preferably at least 7.0 wt.-%, even more preferably at least 8.0 wt.-%, most preferably at least 9.0 wt.-%, and in particular at least 10 wt-%; relative to the total weight of the thus obtained seeded suspension. The process according to any of the preceding claims, wherein in step (c) the amount of seed crystals added to the concentrated composition is at most 24 wt-%; preferably at most 22 wt-%, more preferably at most 20 wt-%, still more preferably at most 18 wt-%, yet more preferably at most 16 wt-%, even more preferably at most 14 wt-%, most preferably at most 12 wt-%, and in particular at most 10 wt-%; relative to the total weight of the thus obtained seeded suspension. The process according to any of the preceding claims, wherein in step (c) the amount of seed crystals added to the concentrated composition is within the range of 10±8.0 wt-%; preferably 10±7.0 wt-%, more preferably 10±6.0 wt-%, still more preferably 10±5.0 wt-%, yet more preferably 10±4.0 wt-%, even more preferably 10±3.0 wt-%, most 10±2.0 wt-%, and in particular 10±1.0 wt-%; relative to the total weight of the thus obtained seeded suspension. The process according to any of the preceding claims, wherein the seed crystals added in step (c) have an average particle size of at least 12 pm, preferably at least 24 pm, more preferably at least 36 pm, still more preferably at least 48 pm, yet more preferably at least 75 pm, even more preferably at least 100 pm, most preferably at least 145 pm, and in particular at least 190 pm; preferably expressed as the geometric mean diameter (dg„) and preferably determined by sieving analysis, preferably in accordance with American Society of Agricultural and Biological Engineers (ASABE), ANSI/ASAE S319.4 FEB2008 "Method of Determining and Expressing Fineness of Feed Materials by Sieving". The process according to any of the preceding claims, wherein the seed crystals added in step (c) have an average particle size of at most 190 pm, preferably at most 145 pm, more preferably at most 100 pm, still more preferably at most 75 pm, yet more preferably at most 48 pm, even more preferably at most 36 pm, most preferably at most 24 pm, and in particular at most 12 pm; preferably expressed as the geometric mean diameter (dg„) and preferably determined by sieving analysis, preferably in accordance with American Society of Agricultural and Biological Engineers (ASABE), ANSI/ASAE S319.4 FEB2008 "Method of Determining and Expressing Fineness of Feed Materials by Sieving". The process according to any of the preceding claims, wherein the seed crystals added in step (c) have an average particle size within the range of 12±10 pm; preferably 12±8.0 pm, more preferably 12±7.0 pm, still more preferably 12±6.0 pm, yet more preferably 12±5.0 pm, even more preferably 12±4.0 pm, most 12±3.0 pm, and in particular 12±2.0 pm; preferably expressed as the geometric mean diameter (dg„) and preferably determined by sieving analysis, preferably in accordance with American Society of Agricultural and Biological Engineers (ASABE), ANSI/ASAE S319.4 FEB2008 "Method of Determining and Expressing Fineness of Feed Materials by Sieving". The process according to any of claims 1 to 36, wherein the seed crystals added in step (c) have an average particle size within the range of 36±24 pm; preferably 36±18 pm, more preferably 36±14 pm, still more preferably 36±10 pm, yet more preferably 36±8.0 pm, even more preferably 36±6.0 pm, most 36±4.0 pm, and in particular 36±2.0 pm; preferably expressed as the geometric mean diameter (dg„) and preferably determined by sieving analysis, preferably in accordance with American Society of Agricultural and Biological Engineers (ASABE), ANSI/ASAE S319.4 FEB2008 "Method of Determining and Expressing Fineness of Feed Materials by Sieving". The process according to any of claims 1 to 36, wherein the seed crystals added in step (c) have an average particle size within the range of 190±178 pm; preferably 190±154 pm, more preferably 190±96 pm, still more preferably 190±48 pm, yet more preferably 190±24 pm, even more preferably 190±12 pm, most 190±6.0 pm, and in particular 190±2.0 pm; preferably expressed as the geometric mean diameter (dg„) and preferably determined by sieving analysis, preferably in accordance with American Society of Agricultural and Biological Engineers (ASABE), ANSI/ASAE S319.4 FEB2008 "Method of Determining and Expressing Fineness of Feed Materials by Sieving". The process according to any of the preceding claims, wherein in step (d) the second temperature is at least 24 °C; preferably at least 26 °C, more preferably at least 28 °C, still more preferably at least 30 °C, yet more preferably at least 32 °C, even more preferably at least 34 °C, most preferably at least 36 °C, and in particular at least 38 °C. The process according to any of the preceding claims, wherein in step (d) the second temperature is at most 56 °C; preferably at most 54 °C, more preferably at most 52 °C, still more preferably at most 50 °C, yet more preferably at most 48 °C, even more preferably at most 46 °C, most preferably at most 44 °C, and in particular at most 42 °C. The process according to any of the preceding claims, wherein in step (d) the second temperature is within the range of 40.0±9.0 °C; preferably 40.0±8.0 °C, more preferably 40.0±7.0 °C, still more preferably 40.0±6.0 °C, yet more preferably 40.0±5.0 °C (i.e. 35.0 to 45.0 °C), even more preferably 40.0±4.0 °C, most preferably 40.0±3.0 °C (i.e. 37.0 to 43.0 °C), and in particular 40.0±2.0 °C (i.e. 38.0 to 42.0 °C). The process according to any of the preceding claims, wherein in step (e) the mechanical energy is introduced without an extruder. The process according to any of claims 1 to 42, wherein in step (e) the mechanical energy is introduced by means of an extruder. The process according to claim 43 or 44, wherein in step (e) the mechanical energy is introduced by an extruder comprising a kneading disk, a kneading block, a reverse screw element, or a combination thereof. The process according to any of claims 43 to 45, wherein the extruder is a single screw extruder, twin screw extruder or planetary roller extruder; preferably wherein the extruder is a twin screw extruder with contrarotating screw configuration or corotating screw configuration. The process according to any of claims 43 to 46, wherein the extruder is equipped with kneading elements. The process according to any of claims 43 to 47, wherein the extruder is equipped with transport elements. The process according to any of claims 43 to 48, wherein the extruder is equipped with a screw or two screws each having a length to diameter ratio (L/D) within the range of from 5 to 50; preferably 10 to 40, or 15 to 35, or 20 to 30. The process according to any of claims 43 to 49, wherein the seeded suspension is subjected to shearing forces in the extruder. The process according to any of claims 43 to 50, wherein the seeded suspension is dried in the extmder under evaporative conditions. The process according to any of claims 43 to 51, wherein the extruder is operated in horizontal arrangement. The process according to any of claims 43 to 52, wherein the extruder has an extrusion chamber in which extrusion is performed over a length of 3.0±2.5 m, more preferably 3.0±2.0 m, still more preferably 3.0±1.5 m, yet more preferably 3.0±1.0 m, even more preferably 3.0±0.5 m. The process according to any of claims 43 to 53, wherein the extruder is operated at an elevated extmsion temperature. The process according to claim 54, wherein the elevated extrusion temperature is at least 30°C; preferably at least 31°C, preferably at least 32°C, preferably at least 33°C, preferably at least 34°C, preferably at least 35°C, preferably at least 36°C, preferably at least 37°C, preferably at least 38°C, preferably at least 39°C, preferably at least 40°C, preferably at least 41 °C, preferably at least 42°C, preferably at least 43 °C, preferably at least 44°C, preferably at least 45°C, preferably at least 46°C, preferably at least 47°C, preferably at least 48°C, preferably at least 49°C, preferably at least 50°C, preferably at least 51 °C, preferably at least 52°C, preferably at least 53°C, preferably at least 54°C, preferably at least 55°C, preferably at least 56°C, preferably at least 57°C, preferably at least 58°C, preferably at least 59°C, preferably at least 60°C. The process according to claim 54 or 55, wherein the elevated extrusion temperature is at most 80°C; preferably at most 79°C, preferably at most 78°C, preferably at most 77°C, preferably at most 76°C, preferably at most 75°C, preferably at most 74°C, preferably at most 73°C, preferably at most 72°C, preferably at most 71 °C, preferably at most 70°C, preferably at most 69°C, preferably at most 68°C, preferably at most 67°C, preferably at most 66°C, preferably at most 65°C, preferably at most 64°C, preferably at most 63°C, preferably at most 62°C, preferably at most 61°C, preferably at most 60°C, preferably at most 59°C, preferably at most 58°C, preferably at most 57°C, preferably at most 56°C, preferably at most 55°C, preferably at most 54°C, preferably at most 53°C, preferably at most 52°C, preferably at most 51°C, preferably at most 50°C. The process according to any of claims 43 to 56, wherein the extruder comprises a first temperature zone operated at temperature Tl, in direction of extrusion followed by a second temperature zone operated at temperature T2, wherein Tl > T2, or T2 > Tl. The process according to any of claims 43 to 57, wherein the extruder comprises a first temperature zone operated at temperature Tl, in direction of extrusion followed by a second temperature zone operated at temperature T2, in direction of extmsion followed by a third temperature zone operated at temperature T3, wherein Tl > T2 > T3, or Tl > T3 > T2, or T2 > Tl > T3, or T2 > T3 > Tl, or T3 > Tl > T2, or T3 > T2 > Tl. The process according to any of claims 43 to 58, which involves conveying in the extruder the seeded suspension containing allulose and a gas phase containing water, wherein the gas phase has a gas pressure that is maintained below atmospheric pressure. The process according to claim 59, wherein the gas pressure is at most 800 mbar; preferably at most 750 mbar, preferably at most 700 mbar, preferably at most 650 mbar, preferably at most 600 mbar, preferably at most 550 mbar, preferably at most 500 mbar, preferably at most 450 mbar, preferably at most 400 mbar, preferably at most 350 mbar, preferably at most 300 mbar, preferably at most 250 mbar, preferably at most 200 mbar, preferably almost 150 mbar, preferably almost 100 mbar, preferably at most 90 mbar, preferably at most 80 mbar, preferably at most 70 mbar, preferably at most 60 mbar, preferably at most 50 mbar, preferably at most 40 mbar, preferably at most 30 mbar, preferably at most 20 mbar, preferably at most 10 mbar. The process according to claim 59 or 60, wherein the gas pressure is at least 40 mbar; preferably at least 60 mbar, more preferably at least 80 mbar, still more preferably at least 100 mbar, yet more preferably at least 120 mbar, even more preferably at least 140 mbar, most preferably at least 160 mbar, and in particular at least 180 mbar. The process according to any of claims 43 to 61, which involves exerting the seeded suspension in the extruder to an increased pressure; preferably of at least 1.5 bar; preferably at least 2.0 bar, preferably at least 2.5 bar, preferably at least 3.0 bar, preferably at least 3.5 bar, preferably at least 4.0 bar, preferably at least 4.5 bar, preferably at least 5.0 bar, preferably at least 6.0 bar, preferably at least 7.0 bar, preferably at least 8.0 bar, preferably at least 9.0 bar, preferably at least 10 bar. The process according to any of claims 43 to 62, which involves expanding the seeded suspension in a compressed state into a vaporized state thereby evaporating water from the allulose composition. The process according to any of claims 43 to 63, wherein the mean residence time of the seeded suspension in the extruder is at least 10 seconds; preferably at least 20 seconds, preferably at least 30 seconds, preferably at least 40 seconds, preferably at least 50 seconds, preferably at least 60 seconds, preferably at least 70 seconds, preferably at least 80 seconds, preferably at least 90 seconds, preferably at least 100 seconds, preferably at least 110 seconds, preferably at least 120 seconds. The process according to any of claims 43 to 64, wherein the mean residence time of the seeded suspension in the extmder is at most 1000 seconds; preferably at most 950 seconds, preferably at most 900 seconds, preferably at most 850 seconds, preferably at most 800 seconds, preferably at most 750 seconds, preferably at most 700 seconds, preferably at most 650 seconds, preferably at most 600 seconds, preferably at most 550 seconds, preferably at most 500 seconds, preferably at most 450 seconds, preferably at most 400 seconds, preferably at most 350 seconds, preferably at most 300 seconds. The process according to any of claims 43 to 65, wherein the extruder is operated at a maximum torque of at least 10 Nm; preferably at least 20 Nm, preferably at least 30 Nm, preferably at least 40 Nm, preferably at least 50 Nm, preferably at least 60 Nm, preferably at least 70 Nm, preferably at least 80 Nm, preferably at least 90 Nm, preferably at least 100 Nm. The process according to any of claims 43 to 66, wherein the extruder is operated at a maximum torque of at most 200 Nm; preferably at most 190 Nm, preferably at most 180 Nm, preferably at most 170 Nm, preferably at most 160 Nm, preferably at most 150 Nm, preferably at most 140 Nm, preferably at most 120 Nm. The process according to any of claims 43 to 67, wherein the extruder is operated at a rotational speed of at least 5 rpm; preferably at least 10 rpm, preferably at least 15 rpm, preferably at least 20 rpm, preferably at least 25 rpm, preferably at least 30 rpm, preferably at least 35 rpm, preferably at least 40 rpm, preferably at least 50 rpm. The process according to any of claims 43 to 68, wherein the extruder is operated at a rotational speed of at most 200 rpm; preferably at most 190 rpm, preferably at most 180 rpm, preferably at most 170 rpm, preferably at most 160 rpm, preferably at most 150 rpm, preferably at most 140 rpm, preferably at most 130 rpm, preferably at most 120 rpm, preferably at most 110 rpm, preferably at most 100 rpm. The process according to any of the preceding claims, wherein in step (e) the mechanical energy is introduced by means of devices which are arranged in series, such that in a first partial step (el) mechanical energy is introduced by means of a first device, and thereafter in a second partial step (e2) further mechanical energy is introduced by means of the second device The process according to any of the preceding claims, wherein in step (e) the mechanical energy is introduced by mixing or stirring. The process according to claim 71, wherein the mechanical energy is introduced by means of a stirrer; preferably selected from the group consisting of spiral stirrer, impeller stirrer, paddle stirrer, propeller stirrer, blade stirrer, oblique blade stirrer, pitched blade propeller stirrer, scroll paddle stirrer, paddle wheel stirrer, disc stirrer, butterfly stirrer, conical cup stirrer, guide rail stirrer, and anchor stirrer; preferably spiral stirrer. The process according to any of claims 71 or 72, wherein in step (e) the mechanical energy is introduced by means of a pressure beater. The process according to claim 73, wherein the pressure beater is equipped with a stator and a rotor which both carry elements, preferably intermeshing shear pins, that introduce high shear forces when the rotor is rotated. The process according to any of claims 71 to 74, wherein the mechanical energy is introduced by stirring at a rotation speed of at least 10 rpm, preferably at least 20 rpm, more preferably at least 30 rpm, still more preferably at least 40 rpm, yet more preferably at least 50 rpm, even more preferably at least 60 rpm, most preferably at least 70 rpm, and in particular at least 80 rpm. The process according to any of claims 71 to 75, wherein the mechanical energy is introduced by stirring at a rotation speed of at least 90 rpm, preferably at least 100 rpm, more preferably at least 110 rpm, still more preferably at least 120 rpm, yet more preferably at least 130 rpm, even more preferably at least 140 rpm, most preferably at least 150 rpm, and in particular at least 160 rpm. The process according to any of claims 71 to 76, wherein the mechanical energy is introduced by stirring at a torque of at least 20 Ncm, preferably at least 40 Ncm, more preferably at least 60 Ncm, still more preferably at least 80 Ncm, yet more preferably at least 100 Ncm, even more preferably at least 120 Ncm, most preferably at least 140 Ncm, and in particular at least 160 Ncm. The process according to any of the preceding claims, wherein step (e) is performed at atmospheric pressure. The process according to any of the preceding claims, wherein step (e) is performed under adiabatic conditions. The process according to any of the preceding claims, wherein in the course of step (e) the temperature and/or the viscosity of the seeded suspension increases. The process according to claim 80, wherein step (e) is commenced at an initial temperature of the seeded suspension, preferably at the first temperature, more preferably at the second temperature, and wherein step (e) is terminated when the temperature of the seeded suspension has reached an end temperature which is higher than the initial temperature. The process according to claim 81, wherein the end temperature is relatively higher by at least 2.0 °C than the initial temperature, preferably by at least 4.0 °C, more preferably by at least 6.0 °C, still more preferably by at least 8.0 °C, yet more preferably by at least 10 °C, even more preferably by at least 12 °C, most preferably by at least 14 °C, and in particular by at least 16 °C. The process according to any of claims 80 to 82, wherein step (e) is commenced at an initial viscosity of the seeded suspension and wherein step (e) is terminated when the viscosity of the seeded suspension has reached an end viscosity which is higher than the initial viscosity. The process according to claim 83, wherein the value of the end viscosity is relatively higher by at least 200 mPa-s than the value of the initial viscosity, preferably by at least 400 mPa-s, more preferably by at least 600 mPa-s, still more preferably by at least 800 mPa-s, yet more preferably by at least 1000 mPa-s, even more preferably by at least 1200 mPa-s, most preferably by at least 1400 mPa-s, and in particular by at least 1600 mPa-s; wherein the initial viscosity is determined at the given temperature of the seeded suspension when step (e) is commenced (initial temperature) and the end viscosity is determined at the given temperature of the seeded suspension when step (e) is terminated (end temperature), preferably by means of a rotary viscosimeter according to ASTM-D2196. The process according to any of claims 80 to 84, wherein step (e) is commenced under conditions where an initial torque would be necessary in order to stir the seeded suspension at a rotational speed of 60 rpm at the given temperature of the seeded suspension when step (e) is commenced (initial temperature), and wherein step (e) is terminated under conditions where an end torque would be necessary in order to stir the seeded suspension at a rotational speed of 60 rpm at the given temperature of the seeded suspension when step (e) is terminated (end temperature), wherein the end torque is higher than the initial torque. The process according to claim 85, wherein the end torque is relatively higher by at least 2.0 Ncm than the initial torque, preferably by at least 4.0 Ncm, more preferably by at least 6.0 Ncm, still more preferably by at least 8.0 Ncm, yet more preferably by at least 10 Ncm, even more preferably by at least 12 Ncm, most preferably by at least 14 Ncm, and in particular by at least 16 Ncm. The process according to claim 85 or 86, wherein the end torque is relatively higher by at least 18 Ncm than the initial torque, preferably by at least 20 Ncm, more preferably by at least 22 Ncm, still more preferably by at least 24 Ncm, yet more preferably by at least 26 Ncm, even more preferably by at least 28 Ncm, most preferably by at least 30 Ncm, and in particular by at least 32 Ncm. The process according to any of the preceding claims, wherein in step (f) the viscous composition is formed into a film having a thickness of at most 35 mm, preferably at most 30 mm, more preferably at most 25 mm, still more preferably at most 20 mm, yet more preferably at most 15 mm, even more preferably at most 10 mm, most preferably at most 5.0 mm, and in particular at most 2.5 mm. The process according to any of the preceding claims, wherein, in step (f) the viscous composition is formed into a film having a thickness of at most 2.4 mm, preferably at most 2.3 mm, more preferably at most 2.2 mm, still more preferably at most 2.1 mm, yet more preferably at most 2.0 mm, even more preferably at most 1.9 mm, most preferably at most 1.8 mm, and in particular at most 1.7 mm. The process according to any of the preceding claims, wherein step (g) is performed for at most 8.0 h, preferably at most 7.0 h, more preferably at most 6.0 h, still more preferably at most 5.0 h, yet more preferably at most 4.0 h, even more preferably at most 3.0 h, most preferably at most 2.0 h, and in particular at most 1.0 h. The process according to any of the preceding claims, wherein in step (g) the viscous composition is allowed to cool to a third temperature below the first temperature and/or the second temperature. The process according to any of the preceding claims, wherein in step (g) the third temperature is at least 16 °C; preferably at least 17 °C, more preferably at least 18 °C, still more preferably at least 19 °C, yet more preferably at least 20 °C, even more preferably at least 21 °C, most preferably at least 22 °C, and in particular at least 23 °C. The process according to any of the preceding claims, wherein in step (g) the third temperature is at most 34 °C; preferably at most 33 °C, more preferably at most 32 °C, still more preferably at most 31 °C, yet more preferably at most 30 °C, even more preferably at most 29 °C, most preferably at most 28 °C, and in particular at most 27 °C. The process according to any of the preceding claims, wherein in step (g) the third temperature is within the range of 25.0±9.0 °C; preferably 25.0±8.0 °C, more preferably 25.0±7.0 °C, still more preferably 25.0±6.0 °C, yet more preferably 25.0±5.0 °C, even more preferably 25.0±4.0 °C, most preferably 25.0±3.0 °C, and in particular 25.0±2.0 °C. The process according to any of the preceding claims, wherein step (g) is performed at an atmospheric relative humidity of at least 3% r.h.; preferably at least 7% r.h., more preferably at least 10% r.h., still more preferably at least 13% r.h., yet more preferably at least 17% r.h., even more preferably at least 20% r.h., most preferably at least 23% r.h., and in particular at least 27% r.h.. The process according to any of the preceding claims, wherein step (g) is performed at an atmospheric relative humidity of at most 87% r.h.; preferably at most 83% r.h., more preferably at most 80% r.h., still more preferably at most 77% r.h., yet more preferably at most 73% r.h., even more preferably at most 70% r.h., most preferably at most 67% r.h., and in particular at most 63% r.h.. The process according to any of the preceding claims, wherein step (g) is performed at an atmospheric relative humidity within the range of 45±40% r.h., preferably 45±35% r.h., more preferably 45±30% r.h., still more preferably 45±25% r.h., bet more preferably 45±20% r.h., and even more preferably 45±15% r.h.. The process according to any of the preceding claims, wherein step (g) is performed at an atmospheric relative humidity of at least 21% r.h.; preferably at least 22% r.h., more preferably at least 23% r.h., still more preferably at least 24% r.h., yet more preferably at least 25% r.h., even more preferably at least 26% r.h., most preferably at least 27% r.h., and in particular at least 28% r.h.. The process according to any of the preceding claims, wherein step (g) is performed at an atmospheric relative humidity of at most 39% r.h.; preferably at most 38% r.h., more preferably at most 37% r.h., still more preferably at most 36% r.h., yet more preferably at most 35% r.h., even more preferably at most 34% r.h., most preferably at most 33% r.h., and in particular at most 32% r.h.. The process according to any of the preceding claims, wherein step (g) is performed at an atmospheric relative humidity within the range of 30±16% r.h.; preferably 30±14% r.h., more preferably 30±12% r.h., still more preferably 30±10% r.h., yet more preferably 30±8% r.h., even more preferably 30±6% r.h., most preferably 30±4% r.h., and in particular 30±2% r.h.. The process according to any of the preceding claims, wherein step (g) is performed at an atmospheric relative humidity of at least 51% r.h.; preferably at least 52% r.h., more preferably at least 53% r.h., still more preferably at least 54% r.h., yet more preferably at least 55% r.h., even more preferably at least 56% r.h., most preferably at least 57% r.h., and in particular at least 58% r.h.. The process according to any of the preceding claims, wherein step (g) is performed at an atmospheric relative humidity of at most 69% r.h.; preferably at most 68% r.h., more preferably at most 67% r.h., still more preferably at most 66% r.h., yet more preferably at most 65% r.h., even more preferably at most 64% r.h., most preferably at most 63% r.h., and in particular at most 62% r.h.. The process according to any of the preceding claims, wherein step (g) is performed at an atmospheric relative humidity within the range of 60±16% r.h.; preferably 60±14% r.h., more preferably 60±12% r.h., still more preferably 60±10% r.h., yet more preferably 60±8% r.h., even more preferably 60±6% r.h., most preferably 60±4% r.h., and in particular 60±2% r.h.. The process according to any of the preceding claims, wherein the solidified allulose composition obtained in step (g) essentially consists of a single solid phase, i.e. does not comprise a separate liquid phase. The process according to any of the preceding claims, wherein the solidified allulose composition obtained in step (g) has a purity of allulose of at least 92%, preferably at least 93%, more preferably at least 94%, still more preferably at least 95%, yet more preferably at least 96%, even more preferably at least 97%, relative to the dry solids content of the solidified allulose composition. The process according to any of the preceding claims, wherein the solidified allulose composition obtained in step (g) has a purity of allulose of at most 99%, preferably at most 98%, more preferably at most 97%, still more preferably at most 96%, yet more preferably at most 95%, relative to the dry solids content of the solidified allulose composition. The process according to any of the preceding claims, wherein in step (h) the solvent is an alcohol or a mixture of an alcohol with water. The process according to claim 107, wherein the alcohol is selected from ethanol and isopropanol; preferably ethanol. The process according to any of the preceding claims, wherein in step (h) the weight ratio of solvent : solidified allulose composition is within the range of from 10:1 to 0.5:1; preferably 5:1 to 1:1. The process according to any of the preceding claims, wherein in step (h) comminuting involves a measure selected from the group consisting of fracturing, breaking, breaking up, hackling, shredding, disintegrating, chopping, shearing, crushing, disrupting, beating, bending, cutting, milling, grinding, and pulverizing. The process according to any of the preceding claims, wherein comminuting in step (h) is performed by means of a mill selected from the group consisting of autogenous mills, ball mills, disintegrators, pulverizers, screen mills, bead mills, disk mills, edge mills, hammer mills, malmal cmshers, jet mills, air jet mills, roll mills, high pressure grinding roll mills, pin mills, planetary mills, vibrational mills, pebble mills, rod mills, SAG mills, and tower mills. The process according to any of the preceding claims, which either comprises alternative (i) of step (h) or alternative (ii) of step (h). The process according to claim 112, which does not include alternative (i) of step (h) and alternative (ii) of step (h) simultaneously. The process according to claim 112 or 113, wherein after the washing in step (h), the thus obtained composition has an increased purity of allulose compared to the solidified allulose composition obtained in step (g); preferably wherein the purity of allulose is relatively increased by at least 0.5%, more preferably at least 1.0%, still more preferably at least 1.5%, yet more preferably at least 2.0%, even more preferably at least 2.5%, most preferably at least 3.0%, and in particular at least 3.5%. The process according to any of claims 112 to 114, wherein after the washing in step (h), the thus obtained composition has a decreased content of fructose compared to the solidified allulose composition obtained in step (g); preferably wherein the content of fructose is relatively decreased by at least 0.1 wt.%, more preferably at least 0.2 wt.-%, still more preferably at least 0.3 wt.-%, yet more preferably at least 0.4 wt.- %, even more preferably at least 0.5 wt-%, most preferably at least 0.6 wt-%, and in particular at least 0.7 wt-%, relative to the total weight of the composition. The process according to any of claims 112 to 115, wherein after the washing in step (h), the thus obtained composition has an increased content of allulose compared to the solidified allulose composition obtained in step (g); preferably wherein the content of allulose is relatively increased by at least 0.5 wt.%, more preferably at least 1.0 wt-%, still more preferably at least 1.5 wt-%, yet more preferably at least 2.0 wt- %, even more preferably at least 2.5 wt-%, most preferably at least 3.0 wt-%, and in particular at least 3.5 wt-%, relative to the total weight of the composition. The process according to any of claims 112 to 116, wherein after the washing in step (h), the thus obtained composition has an increased dry solids content compared to the solidified allulose composition obtained in step (g); preferably wherein the dry solids content is relatively decreased by at least 0.1 wt.%, more preferably at least 0.2 wt-%, still more preferably at least 0.3 wt-%, yet more preferably at least 0.4 wt- %, even more preferably at least 0.5 wt-%, most preferably at least 0.6 wt-%, and in particular at least 0.7 wt-%, relative to the total weight of the composition. The process according to any of claims 112 to 117, wherein after the washing in step (h), the thus obtained composition has a decreased color compared to the solidified allulose composition obtained in step (g). The process according to any of the preceding claims, wherein the particulate allulose composition has a degree of crystallinity of at least 1%; preferably at least 2%, preferably at least 3%, preferably at least 4%, preferably at least 5%, preferably at least 6%, preferably at least 7%, preferably at least 8%, preferably at least 9%, preferably at least 10%. The process according to any of the preceding claims, wherein the particulate allulose composition has a degree of crystallinity of at most 90%; preferably at most 80%, preferably at most 70%, preferably at most 60%, preferably at most 50%, preferably at most 40%, preferably at most 30%, preferably at most 20%, preferably almost 15%, preferably almost 10%, preferably at most 7.5%, preferably at most 5%, preferably at most 2.5%, preferably at most 1%. The process according to any of the preceding claims, wherein the particulate allulose composition is essentially amorphous. A particulate allulose composition obtainable by the process according to any of the preceding claims. A particulate allulose composition, preferably according to claim 122, having a dissolution behavior such that when 100.0 g of the particulate allulose composition are dissolved in 100.0 mL of pure water having a temperature of 23.0 °C under stirring, the temperature of the thus obtained solution relatively decreases reaching a minimum of at least 18.3 °C, preferably at least 18.7 °C, still more preferably at least 19.0 °C, yet more preferably at least 20.0 °C, even more preferably at least 19.3 °C, most preferably at least 19.7 °C, and in particular at least 20.0 °C. A particulate allulose composition, preferably according to claim 122 or 123, having a solution enthalpy, preferably determined according to the method as described herein, of at most 13.0 cal/g, preferably at most 12.9 cal/g, more preferably at most 12.8 cal/g, still more preferably at most 12.7 cal/g, yet more preferably at most 12.6 cal/g, even more preferably at most 12.5 cal/g, most preferably at most 12.4 cal/g, and in particular at most 12.3 cal/g. The particulate allulose composition according to claim 124, wherein the solution enthalpy is at most 12.2 cal/g, preferably at most 12.1 cal/g, more preferably at most 12.0 cal/g, still more preferably at most 11.9 cal/g, yet more preferably at most 11.8 cal/g, even more preferably at most 11.7 cal/g, most preferably at most 11.6 cal/g, and in particular at most 11.5 cal/g. The particulate allulose composition according to claim 125, wherein the solution enthalpy is at most 11.4 cal/g, preferably at most 11.3 cal/g, more preferably at most 11.2 cal/g, still more preferably at most 11.1 cal/g, yet more preferably at most 11.0 cal/g, even more preferably at most 10.9 cal/g, most preferably at most 10.8 cal/g, and in particular at most 10.7 cal/g. The particulate allulose composition according to any of claims 122 to 126, wherein the solution enthalpy is at least 7.0 cal/g, preferably at least 7.5 cal/g, more preferably at least 8.0 cal/g, still more preferably at least 8.5 cal/g, yet more preferably at least 9.0 cal/g, even more preferably at least 9.5 cal/g, most preferably at least 10.0 cal/g, and in particular at least 10.5 cal/g. The particulate allulose composition according to any of claims 122 to 127, wherein the solution enthalpy is within the range of 9.0±1.6 cal/g, preferably 9.0±1.4 cal/g, more preferably 9.0±1.2 cal/g, still more preferably 9.0±1.0 cal/g, yet more preferably 9.0±0.8 cal/g, even more preferably 9.0±0.6 cal/g, most preferably 9.0±0.4 cal/g, and in particular 9.0±0.2 cal/g. The particulate allulose composition according to any of claims 122 to 127, wherein the solution enthalpy is within the range of 10.0±1.6 cal/g, preferably 10.0±1.4 cal/g, more preferably 10.0±1.2 cal/g, still more preferably 10.0±1.0 cal/g, yet more preferably 10.0±0.8 cal/g, even more preferably 10.0±0.6 cal/g, most preferably 10.0±0.4 cal/g, and in particular 10.0±0.2 cal/g. The particulate allulose composition according to any of claims 122 to 127, wherein the solution enthalpy is within the range of 11.0±1.6 cal/g, preferably 11.0±1.4 cal/g, more preferably 11.0±1.2 cal/g, still more preferably 11.0±1.0 cal/g, yet more preferably 11.0±0.8 cal/g, even more preferably 11.0±0.6 cal/g, most preferably 11.0±0.4 cal/g, and in particular 11.0±0.2 cal/g. The particulate allulose composition according to any of claims 122 to 127, wherein the solution enthalpy is within the range of 12.0±1.6 cal/g, preferably 12.0±1.4 cal/g, more preferably 12.0±1.2 cal/g, still more preferably 12.0±1.0 cal/g, yet more preferably 12.0±0.8 cal/g, even more preferably 12.0±0.6 cal/g, most preferably 12.0±0.4 cal/g, and in particular 12.0±0.2 cal/g. A particulate allulose composition, preferably according to any of claims 122 to 131, having a particle shape determined by dynamic image analysis in accordance with ISO 13322-2, wherein the quotient of - the ratio b/1 of particle breadth b to particle length 1 measured at a dispersion pressure of 460 Pa and - the ratio b/1 of particle breadth b to particle length 1 measured at a dispersion pressure of 5 Pa is at most 1.40, preferably at most 1.35, more preferably at most 1.30, still more preferably at most 1.25, yet more preferably at most 1.20, even more preferably at most 1.15, most preferably at most 1.10, and in particular at most 1.05. |
[0001] Priorities are claimed of European patent application no. 22193439.1 (filed 01.09.2022), European patent application no. 22200973.0 (filed 11.10.2022), European patent application no. 22200974.8 (filed 11.10.2022), European patent application no. 23152846.4 (filed 23.01.2023), and European patent application no. 23152845.6 (filed 23.01.2023).
[0002] The invention relates to a process for the preparation of a particulate allulose composition, the process comprising the steps of providing an aqueous allulose syrup; evaporating water from the allulose syrup; allowing the composition to solidify; and washing the solidified allulose composition thereby obtaining the particulate allulose composition. The invention further relates to the particulate allulose composition that is obtainable by said process.
[0003] Allulose can be prepared from fmctose by enzymatical catalysis. Known processes for the preparation of allulose aim at providing either highly concentrated aqueous allulose solutions (allulose syrups) or crystalline allulose material obtained from such allulose syrups by crystallization.
[0004] From an economical perspective, preparation of allulose symps on the one hand is advantageous because it requires less energy, equipment and time. However, allulose syrups have disadvantages not only with respect to transportation costs, but particularly also with respect to storage stability and shelf life. Upon storage for several months at ambient temperature, the allulose content of allulose syrups decreases, the fructose content increases, the content of hydroxymethyl furfural (HMF) increases, and the color changes into brown. Factors influencing storage stability and shelf life include byproducts that are formed during preparation and that are not separated from the allulose syrups, as well as storage time and storage temperature.
[0005] Preparation of crystalline allulose materials on the other hand has the advantage of significantly improved storage stability and shelf life. However, crystallization processes have a higher energy consumption and require extended crystallization time and work up, often several days or even weeks. Moreover, yields are low, typically about 50%.
[0006] WO 2008 147723 discloses substantially water soluble, substantially non-dusting delivery systems for natural high-potency sweeteners, methods for their formulation, and uses.
[0007] WO 2011 119004 relates to a method of producing D-psicose crystals from a D-psicose solution by using supersaturation.
[0008] WO 2013 103106 aims at providing a homogeneous sugar composition containing sucrose and D-psicose. A sugar composition containing sucrose and D-psicose is provided, wherein crystals of the sucrose are coated with the D-psicose in a crystalline or amorphous state. The content of the D-psicose is 1 part by weight or more and 50 parts by weight or less relative to 100 parts by weight of the total weight of the sucrose and the D-psicose.
[0009] WO 2014 161977 concerns a composition for a non-cariogenic confectionery or pharmaceutical product obtained by a hard sugar-coating method, and having improved crispiness.
[0010] WO 2015 075473 relates to the use of high levels of allulose in food and beverage products. [0011] WO 2016 064087 discloses a method for producing high purity D-psicose crystals having a purity of 98% (w/w) or more and a grain size of MA200 or more. The method includes: removing impurities from a D-psicose solution to obtain a purified D-psicose solution; concentrating the purified D-psicose solution; cooling the concentrated D-psicose solution to 30 °C to 40 °C through a heat exchanger; seed crystallizing the D-psicose solution at 30 °C to 40 °C to obtain a seed crystallized massecuite; and full-scale crystallizing the seed crystallized massecuite. The method can produce pure D-psicose crystals in a suitable form for industrial application through an economical crystallization process from the D-psicose solution without using organic solvents.
[0012] WO 2016 135458 relates to allulose syrups, use of allulose syrups in the manufacture of food or beverage products, and food and beverage products made using the allulose syrups.
[0013] WO 2016 156117 relates to a chewing gum composition comprising crystalline allulose particles and optionally an aqueous allulose syrup, and to the use of allulose for increasing the hardening rate of chewing gum compositions.
[0014] WO 2016 186338 relates to a mixed saccharide composition containing psicose, glucose and fructose with improved sweetness quality and crystallization, and a method for preventing crystallization of a mixed saccharide composition containing a psicose.
[0015] WO 2016 210169 relates to a system can be used to process liquid materials, such as aqueous-based syrup solutions containing sugar molecules. In some examples, the system includes a processing vessel having multiple individually-controllable temperature zones arranged in series.
[0016] WO 2017029 244 relates to a powder comprising allulose, wherein the average particle size of the powder is within the range of at most 5.0 mm, preferably within the range of (i) at most 900 pm; (ii) from 900 pm to 2.0 mm; or (iii) from 2.0 mm to 5.0 mm.
[0017] WO 2017 059352 relates to a low calorie, low taxation confection such as chewy candy, hard candy, tableted candy, or gelled candy having acceptable texture, stability, clarity, and flavor delivery that contains a bulk sweetener comprising allulose (psicose). Allulose is combined with sugars, carbohydrates, or polyols to make consumer acceptable confections.
[0018] WO 2017 059363 discloses chewing gums containing allulose and methods of making such gums. In one embodiment, the gum comprises about 5% to about 95% gum base, about 0.1% to about 10% flavoring agent and allulose, the allulose being part or all of the bulk sweetener in the gum. The allulose provides the gum with unique properties; the gum is low in calories and may be non-cariogenic. In other embodiments, the allulose is co-dried with other sweeteners or co-evaporated with other sweeteners or with a plasticizing syrup to produce sweetening ingredients and syrups for gum.
[0019] WO 2017 150766 relates to a method of producing D-psicose including the steps of subjecting D-fructose to D-psicose epimerization to produce a D-psicose-containing solution, subjecting the D-psicose-containing solution to first cooling and ion purification, subjecting the purified D-psicose-containing solution to first concentration and second cooling, subjecting the D-psicose-containing solution, which has been subjected to first concentration and second cooling, to chromatography to obtain a D-fructose-containing mother liquor and a D-psicose-contain- ing separated solution, and subjecting the D-psicose-containing separated solution to second concentration and third cooling to obtain D-psicose crystals, wherein the D-fructose-containing mother liquor produced by chromatography is reused in the D-psicose epimerization.
[0020] WO 2017 155261 discloses a symp composition and a food comprising the same. The syrup composition includes: gum, pectin, or a combination thereof; and allulose.
[0021] WO 2018 029351 relates to an aqueous liquid composition comprising allulose, wherein the weight content of allulose is at least 10 wt.-%, relative to the total weight of the liquid composition; and wherein the weight content of allulose is at least 10 wt-%, relative to the total content of all carbohydrates that are contained in the liquid composition; and wherein the liquid composition has a viscosity of at most 200 mPa s.
[0022] WO 2018 081557 relates to a method wherein allulose crystals are efficiently produced from an allulose syrup using seed crystals.
[0023] WO 2018 099479 discloses a method for preparing high-purity D-psicose, comprising the step of subjecting a crude D-psicose solution to decolorization, filtration, ion exchange, chromatographic separation, concentration, and then crystallization or drying, obtaining D-psicose.
[0024] WO 2018 105 931 relates to a method for preparing psicose by introducing and recycling a psicose crystallization mother liquor obtained from a psicose crystallization process into at least one process selected from the group consisting of an activated carbon treatment process, an ion purification process, a simulated moving bed chromatographic separation process, and a process for concentrating a psicose fraction.
[0025] WO 2018 127668 discloses a method for producing D-allulose crystals that allows for a continuous production process and ensures a high yield. A nanofiltration unit is used for producing D-allulose crystals to improve the yield and/or quality of the resulting crystals.
[0026] WO 2018 127669 discloses a D-allulose syrup including, besides D-allulose, a D-allulose dimer mass content, expressed in terms of dry mass, lower than 1.5%. Also, a method for producing the syrup and to the use thereof for producing food or pharmaceutical products is disclosed.
[0027] WO 2018 127670 relates to a D-allulose syrup including, besides D-allulose, a D-allulose dimer mass content, expressed in terms of dry mass, greater than 1.5%.
[0028] WO 2018 149 707 provides a process for production of a solid material containing isomaltulose crystals and trehalulose.
[0029] WO 2019 004 554 relates to a method for producing a functional crystalline sweetener, and, more specifically, to a method for producing a crystalline sweetener for improving crystal yield and increasing particle size by controlling the content of impurities included in a solution for producing crystals, or the generation of the impurities.
[0030] WO 2019 082 206 discloses a sweetener formulation for enhancing the sweetness, creating upfront taste profde and mouth fullness of low intensity sweeteners / less sweetening sugars (rare sugars) comprising at least two of the ingredients selected from (a) rare sugars; (b) disaccharides or (c) oligosaccharides and/or polysaccharides.
[0031] WO 2019 083 069 relates to an allulose syrup and a method for manufacturing same. The allulose symp comprises a viscosity controlling agent and a dispersing agent, and has an appropriate range of viscosity. [0032] WO 2019 088 654 relates to a syrup comprising a citrus extract and saccharides including allulose; a method for manufacturing the syrup, the method comprising a step for mixing the citrus extract, the saccharides including allulose and an acidity regulator; a food composition comprising the syrup comprising the citrus extract and the saccharides including allulose; a flavor-improving composition comprising the citrus extract and the saccharides including allulose; a method for improving the flavor retention of the citms extract, the method comprising a step for adding the saccharides including allulose to the citms extract; and a flavor-manifesting composition comprising the citrus extract and the saccharides including allulose.
[0033] WO 2020 005 021 relates to a sweetener powder composition and a preparation method therefor and, more specifically, to a sweetener powder composition for preparing an amorphous powder containing a functional sweetener and a preparation method therefor.
[0034] WO 2020 111 851 relates to a preparation method for a D-psicose crystal containing 98% (w/w) or more D-psicose and 0.05% (w/w) or less ethanol based on 100% (w/w) of the entire crystal. The preparation method includes a first step of mixing a D-psicose-containing solution and an organic solvent, and a second step of adding a seed to the mixed solution according to the first step and then cooling the same to obtain a massecuite containing the D-psicose crystal.
[0035] WO 2021 160 564 relates to allulose concentrates in solid amorphous form, which are characterized in that they contain at least approximately 20 wt. % allulose.
[0036] WO 2021 160701 relates to a crystalline allulose with a defined particle size distribution, to a process for the production and use thereof. The allulose quality is characterized by the fact that it improves the shelf life of end products made therewith as well as their sensory and taste properties.
[0037] WO 2022 049307 relates to a process for the preparation of a product allulose composition comprising the steps of (a) providing a liquid allulose composition comprising allulose dissolved in water; (b) optionally, heating the liquid allulose composition to an elevated temperature, preferably under evaporative conditions thereby reducing the content of water of the allulose composition; (c) feeding the allulose composition into an extruder; (d) extruding the allulose composition in the extruder; (e) obtaining a product allulose composition from the extruder; (f) optionally, allowing the product allulose composition to solidify; and (g) optionally, grinding and/or post-drying the product allulose composition.
[0038] US 2020 0196648 relates to functional saccharides having specific crystallinity, a method for preparing thereof, and a functional sweetener comprising the crystalline saccharides.
[0039] CN 104 447 888 discloses preparing a crystal allulose product by virtue of working procedures such as chemical differential phase isomerism, refined chromatography separation and purification, concentration and crystallization and the like by adopting glucose as the raw material.
[0040] CN 106 480 125 relates to a method using a solid D-psicose3 -epimerase to convert fmctose to obtain a conversion solution containing high-concentration D-psicose. A cooling crystallization process is used for crystallizing the conversion solution to obtain the high-concentration D-psicose crystal.
[0041] CN 107 699 557 discloses a method for preparation of high-purity D-psicose comprising the step of performing chromatographic separation, concentration, crystallization or drying on a D-psicose solution to obtain D- psicose. [0042] CN 110 872 332 discloses a method for preparing allulose crystals by a two-step process, wherein in a first step an allulose-containing solution is concentrated and preliminary crystallized under reduced pressure and in a second step is deep crystallized via cooling crystallization.
[0043] CN 114 031649 relates to a method for improving the particle size and fluidity of psicose crystals. Seed crystals are obtained through grinding, sieving, ethanol washing, and sieving again; specifically, through grinding and sieving, taking the crystals of particle size 40-60, adding ethanol solution in a ratio of 2, and sieving again after grinding to obtain crystals with a particle size of 100.
[0044] CN 215 139134U discloses a device for producing psicose, belonging to the technical field of psicose production, comprising a mixer, wherein the top of the mixer is communicated with a solid feeding mechanism and a liquid feeding mechanism; the bottom of blender intercommunication has the auger, and the auger intercommunication has the shale shaker, and the shale shaker intercommunication has the magnet separator, and the magnet separator intercommunication has the feed bin.
[0045] KR 2016 062 349 relates to a method for producing D-psicose having high purity of 99% (w/w) or higher comprising the step of concentrating a D-psicose solution, performing heat exchange cooling on the D-psicose solution, crystallizing the D-psicose solution; performing heat exchange cooling on a crystallization separation base solution, and re-circulating the crystallization separation base solution within a procedure. A continuous chromatography separation fmctose base solution and a crystallization separation base solution are collected and fed during an enzyme reaction procedure, so D-psicose may be stably separated through continuous chromatography despite long-term recirculation thereof.
[0046] There is a demand for allulose preparations that have advantages compared to the allulose preparations of the prior art. The allulose preparations should be colorless or only have a low degree of coloration, should contain allulose at high purity, and should contain no water or only a minor residual amount of water. Further, there is a demand for processes that make available such allulose preparations in a time efficient and economic manner.
[0047] It is an object of the invention to provide allulose compositions that have excellent storage stability and shelf life at low transportation costs. The allulose preparations should be obtainable at high yields and purity in shortened process times. The processes for preparation of the allulose compositions should have a high throughput, low energy consumption, and should not require sophisticated processing equipment.
[0048] This object has been achieved by the subject-matter of the patent claims.
[0049] It has been surprisingly found that highly concentrated aqueous allulose compositions containing seed crystals of allulose become viscous when sufficient mechanical energy is introduced. Introduction of mechanical energy can simply be achieved by mixing or stirring and thus does not require an extruder or similar sophisticated equipment. The process according to the invention can be advantageously integrated in processes for the synthesis of allulose, preferably after a concentration step where the concentration of allulose is increased in order to obtain allulose syrups.
[0050] In spite of their oversaturation, highly concentrated aqueous allulose compositions having dry substance contents of 90 wt.-% or more do not spontaneously crystallize or congeal even in presence of significant amounts of seed crystals of allulose. For that reason, conventional processes for the preparation of crystalline allulose composition require extended periods of time. It has now been surprisingly found that the impeded crystallization may be overcome by introducing mechanical energy, preferably by vigorous stirring. As a consequence of introducing mechanical energy, the temperature of the thus treated composition increases. While one would expect that such temperature increase reduces viscosity thereby facilitating e.g. stirring, the opposite has been observed.
[0051] It has been surprisingly found that in the course of introducing mechanical energy e.g. by stirring, at least the following three stages can be distinguished: initial stage with slight temperature increase, intermediate stage with roughly constant temperature, and final stage with sudden temperature increase. For example, when the initial temperature is 40°C, during the initial stage the temperature of the composition is increased from 40°C to about 45-50°C. Depending upon the equipment used and the amount of mechanical energy thus introduced, the subsequent intermediate stage may last e.g. for about 30 to 120 minutes and temperature does not significantly further increase. At the final stage, the temperature suddenly increases again, e.g. from about 50°C to more than about 60°C. At this point, introduction of mechanical energy can be terminated and the composition can be allowed to solidify (congealing point). It has been surprisingly found that the higher the purity of the allulose, i.e. the content of allulose relative to the dry solids content of the aqueous composition, the faster the temperature increase.
[0052] Further, it has been surprisingly found that besides temperature, the viscosity of the composition changes as well. It has been found that in the course of introducing mechanical energy e.g. by stirring, the viscosity of the composition steadily increases, i.e. the force (torque) increases that would be necessary in order to stir the composition at constant rotational speed. The faster and more vigorous the mixing of the composition, the earlier solidification of the composition can be achieved. The higher temperature and torque, the closer the composition will be to its congealing point.
[0053] It has been surprisingly found that once the final stage has been reached, the thus obtained composition can still be processes by conventional equipment and can e.g. be poured onto trays thus providing a film of the composition. Within a short period of time, this film congeals and solidifies when being stored under suitable conditions. The thus obtained solidified material can then be comminuted (e.g. fractured, broken, broken up, hack- led, shred, disintegrated, chopped, sheared, crushed, dismpted, ruptured, beaten, bent, cut, milled, ground, pulverized, and the like) into a particulate allulose composition by means of conventional equipment. The thus obtained solidified material is not tacky and therefore does not adhere to conventional grinding equipment such as mills.
[0054] It has been surprisingly found that the process according to the invention provides a particulate allulose composition within a short period of time after evaporation, typically within less than 2 hours. Compared to conventional crystallization processes, the overall yield is much higher and approximates 100% with respect to the solids content of the starting material.
[0055] Moreover, it has been surprisingly found that the particulate allulose compositions can be easily purified by means of organic solvents, e.g. ethanol. Immersing the particles to organic solvents significantly decreases color, increases allulose purity, and decreases residual water content after drying. Further, dry substance content is increased thereby allowing for shorter solidifying times.
[0056] Further, it has been surprisingly found that the thus obtained particulate allulose composition has unique properties and differs from the crystalline, semi-crystalline or amorphous solid allulose preparations of the prior art. Allulose has a positive standard enthalpy change of solution (AH soiu tion), i.e. heat is absorbed during the dissolving process. Compared to conventional solid allulose preparations, however, less heat is absorbed during dissolving the particulate allulose composition according to the invention in water . This has advantages with respect to the preparation of beverages and other food preparations that require dissolving solid allulose.
[0057] Yet further, it has been surprisingly found that the thus prepared particulate allulose compositions are ready to use and provide a fast dissolution rate. They have a comparatively low weight, i.e. can be shipped at low transportation costs, can be used as powdery bulk material, and have good storage stability.
[0058] A first aspect of the invention relates to a process for the preparation of a particulate allulose composition, the process comprising the steps of
(a) providing an aqueous allulose syrup comprising allulose essentially in dissolved form at a purity of at least 90.0 wt-%, relative to the dry solids content of the allulose symp;
(b) evaporating water from the allulose syrup at a first temperature thereby obtaining an concentrated composition having a dry solids content of at least 90.0 wt.-%, relative to the total weight of the concentrated composition;
(c) optionally, adding seed crystals of allulose to the concentrated composition thereby obtaining a seeded suspension;
(d) optionally, adjusting the temperature of the seeded suspension to a second temperature differing from the first temperature;
(e) optionally, introducing mechanical energy into the seeded suspension thereby obtaining a viscous composition;
(f) optionally, forming the viscous composition into a film;
(g) allowing the concentrated composition, seeded suspension or viscous composition to solidify thereby obtaining a solidified allulose composition; and
(h) purifying the solidified allulose composition by (i) washing the solidified allulose composition with a solvent; or (ii) comminuting the solidified allulose composition and washing the comminuted allulose composition with a solvent; thereby obtaining the particulate allulose composition.
[0059] Unless expressly stated otherwise, for the purpose of the specification, all percentages are weight percent and ppm are parts per million by weight (ppmw).
[0060] The process steps of the process according to the invention are performed in alphabetical order, whereas steps (c), (d), (e) and (f) are optional. Step (h) comprises two alternatives, (i) and (ii), that are preferably not performed both. Thus, when the process comprises alternative (i) of step (h), the process preferably does not include alternative (ii) of step (h). When the process comprises alternative (ii) of step (h), the process likewise preferably does not include alternative (i) of step (h).
[0061] In preferred embodiments, the invention relates to a process for the preparation of a particulate allulose composition, the process comprising the steps of (a) providing an aqueous allulose syrup comprising allulose essentially in dissolved form at a purity of at least 90.0 wt.-%, relative to the dry solids content of the allulose symp;
(b) evaporating water from the allulose syrup at a first temperature thereby obtaining an concentrated composition having a dry solids content of at least 90.0 wt-%, relative to the total weight of the concentrated composition;
(g) allowing the concentrated composition to solidify thereby obtaining a solidified allulose composition; and
(h) purifying the solidified allulose composition by washing the solidified allulose composition with a solvent thereby obtaining the particulate allulose composition.
[0062] In other preferred embodiments, the invention relates to a process for the preparation of a particulate allulose composition, the process comprising the steps of
(a) providing an aqueous allulose syrup comprising allulose essentially in dissolved form at a purity of at least 90.0 wt.-%, relative to the dry solids content of the allulose symp;
(b) evaporating water from the allulose syrup at a first temperature thereby obtaining an concentrated composition having a dry solids content of at least 90.0 wt.-%, relative to the total weight of the concentrated composition;
(g) allowing the concentrated composition to solidify thereby obtaining a solidified allulose composition; and
(h) purifying the solidified allulose composition by comminuting the solidified allulose composition and washing the comminuted allulose composition with a solvent; thereby obtaining the particulate allulose composition.
[0063] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (g) and (h), but does not include steps (c), (d), (e) and (f).
[0064] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (c), (g) and (h), but does not include steps (d), (e) and (f).
[0065] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (d), (g) and (h), but does not include steps (c), (e) and (f).
[0066] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (e), (g) and (h), but does not include steps (c), (d) and (f).
[0067] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (f), (g) and (h), but does not include steps (c), (d) and (e).
[0068] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (c), (d), (g) and (h), but does not include steps (e) and (f).
[0069] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (c), (e), (g) and (h), but does not include steps (d) and (f).
[0070] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (c), (f), (g) and (h), but does not include steps (d) and (e).
[0071] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (d), (e), (g) and (h), but does not include steps (c) and (f). [0072] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (d), (f), (g) and (h), but does not include steps (c) and (e).
[0073] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (e), (f), (g) and (h), but does not include steps (c) and (d).
[0074] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (c), (d), (e), (g) and (h), but does not include step (f).
[0075] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (c), (d), (f), (g) and (h), but does not include step (e).
[0076] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (c), (e), (f), (g) and (h), but does not include step (d).
[0077] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (d), (e), (f), (g) and (h), but does not include step (c).
[0078] In preferred embodiments, the process according to the invention comprises or essentially consists of steps (a), (b), (c), (d), (e), (f), (g) and (h).
[0079] It is contemplated that the process according to the invention includes additional steps that may be performed prior to step (a), after step (h) or in between any of steps (a) to (h). Thus, when e.g. a concentrated composition is obtained as intermediate product of step (b) and said concentrated composition is further processed in subsequent step (c), it is contemplated that additional measures are taken after step (b) has been completed and before step (c) is commenced. It is also contemplated that some or more steps are performed simultaneously or partially simultaneously.
[0080] Preferably, the process according to the invention is operated continuously or semi-continuously.
[0081] In a preferred embodiment, the process is operated semi-continuously in an evaporator and at least a first stirring vessel and a second stirring vessel. According to this embodiment, step (b) is performed continuously in the evaporator thereby producing concentrated composition in accordance with step (b). The thus obtained concentrated composition is continuously supplied to the first stirrer vessel until said first stirrer vessel has been filled with a desired amount of concentrated composition. Thereafter, supply is switched from the first stirrer vessel to the second stirrer vessel, i.e. the concentrated composition is then continuously supplied to the second stirrer vessel until said second stirrer vessel has been filled with a desired amount of concentrated composition. Optionally, when a third stirrer vessel is involved, supply is switched from the second stirrer vessel to the third stirrer vessel, i.e. the concentrated composition is continuously supplied to the third stirrer vessel until said third stirrer vessel has been filled with a desired amount of concentrated composition, and so on. Once a given stirrer vessel has been filled with a desired amount of concentrated composition, the necessary amount of seed crystals of allulose are added in accordance with step (c), the temperature of the seeded suspension in the stirrer vessel is optionally adjusted in accordance with step (d), and mechanical energy is introduced into the seeded suspension by stirring in accordance with step (e). According to this embodiment, the evaporation rate on the one hand is synchronized with the solidification rate on the other hand. This means that the time needed for producing the desired amount of concentrated composition in accordance with step (b), i.e. the evaporation rate, is adjusted to the number and the volume of stirring vessels and to the time needed for seeding in step (c), adjusting the temperature in optional step (d), and introducing mechanical energy by stirring in step (e) until the viscous composition is obtained. When two identical stirring vessels are used, seeding, adjusting temperature and stirring are performed in the first stirring vessel during supply of the second stirring vessel with concentrated composition, and vice versa. Supply of concentrated composition to the second stirring vessel is terminated just when the production of viscous composition in the first stirring vessel has been completed and the first stirring vessel has been emptied, and so on.
[0082] Allulose, also referred to as "psicose", is a ketohexose. For the purpose of the specification, allulose is preferably provided in form of the D-enantiomer, i.e. D-allulose (CAS no. 551-68-8), which in open chain Fischer projection has the following structure:
D-allulose
[0083] D-allulose can be present in form of the two enantiomers, D-allulose and L-allulose. According to the invention, allulose is present essentially only in form of the D-enantiomer. Thus, unless expressly stated otherwise, the term "allulose" as used herein refers to D-allulose (D-psicose).
[0084] Likewise, unless expressly stated otherwise, the term "fructose" as used herein refers to D-fmctose.
[0085] Unless expressly stated otherwise, "essentially" refers to a quantitative degree of at least 99.0%, more preferably at least 99.5%, and in particular at least 99.9%.
[0086] Unless expressly stated otherwise, all conditions are ambient conditions, i.e. room temperature (23°C), 1013 hPa atmospheric pressure, and 50% relative humidity.
[0087] In order for a particulate product to emerge from a liquid, it is not sufficient to achieve appropriate thermodynamic states, because surface energy and kinetic factors also play an important role in the creation of the new particulate phase. Therefore, the point must be exceeded which is thermodynamically necessary for the creation of the new phase. If particles are to be created from a solution, this excess is supersaturation, while for the creation of particles from a melt, undercooling is necessary.
[0088] When trying to obtain a particulate allulose product from a highly concentrated aqueous allulose solution (allulose syrup), various factors need to be taken into account, especially mass fraction of allulose in the starting material, temperature, pressure, presence or absence of nucleation sites, entropy reducing effects (e.g. shear forces), and the like.
[0089] Depending upon the given experimental conditions, the process can be regarded as a crystallization/pre- cipitation of particles from solution; or the process according to the invention can be regarded as a solidification from a melt. In reality, both processes may superimpose one another. Therefore, supersaturation as well as undercooling can both play an important role. [0090] Under thermodynamic control (slow, low supersaturation), relatively few large crystals typically form from a solution (crystallization). Under kinetic control (fast, high supersaturation), a relatively large number of small particles are formed, which can be amorphous or crystalline (precipitation). When solidifying from a melt, a crystalline or amorphous solid forms, which can be monolithic or more or less particulate.
[0091] In reality experimental conditions cannot be freely chosen. For example, for economic and other reasons, the process according to the invention needs to be performed in a timely manner at reasonable energy consumption. Thus, the residence time of the material in the equipment for performing the process is limited. Further, evaporation conditions should achieve a satisfactory evaporation rate of water typically requiring elevated temperature and/or reduced pressure. However, the properties of allulose also play an important role and highly depend upon the given temperature as well. Thus, process conditions need to be between the properties of water on the one hand and the properties of allulose on the other hand.
[0092] As the properties of allulose differ from the properties of other saccharides, experimental conditions that have been revealed to be suitable for one saccharide cannot be easily transferred to allulose. In other words, the binary system of allulose in water shows a specific behavior that differs from that of binary systems of other carbohydrates in water.
[0093] Expressed as a mass fraction, the solubility of allulose in water increases with increasing temperature. 291 g of allulose (74% solubility) dissolve in 100 g of water at 25 °C, and 489 g of allulose (83% solubility) at 50 °C. Allulose is less soluble in water than fructose and more soluble than glucose and lactose. Compared to invert sugar, allulose is more soluble in water at room temperature; the solubility is comparable at higher temperatures. Compared to sucrose, allulose is less soluble at temperatures below room temperature, at higher temperatures the solubility of allulose is better than that of sucrose.
[0094] Step (a)
[0095] In step (a) of the process according to the invention, an aqueous allulose syrup is provided which comprises allulose essentially in dissolved form at a purity of at least 90.0 wt.-%, relative to the dry solids content of the allulose syrup.
[0096] Preferably, the aqueous allulose syrup is a highly concentrated aqueous solution essentially containing no undissolved material.
[0097] Preferably, the aqueous allulose syrup has a viscosity at room temperature (23 °C) within the range of from 100 to 250 mPa s.
[0098] In preferred embodiments, the aqueous allulose syrup provided in step (a) of the process according to the invention is a mother liquor that originates from a process for the crystallization of allulose from solution. As processes for the crystallization of allulose from solution have a comparatively low yield, they produce as byproducts significant volumes of mother liquor containing significant quantities of dissolved allulose which may then advantageously be solidified by means of the process according to the invention.
[0099] It has been surprisingly found that highly concentrated solutions of allulose, from which allulose cannot be crystallized (residual mother liquor), can advantageously be employed as starting material in the process according to the invention. [0100] Preferably, the total weight content of allulose, fructose, glucose, sucrose and water of the aqueous allulose syrup provided in step (a) is at least 65 wt-%; more preferably at least 70 wt-%, still more preferably at least 75 wt-%, yet more preferably at least 80 wt-%, even more preferably at least 85 wt-%, and most preferably at least 90 wt-%; relative to the total weight of the aqueous allulose syrup.
[0101] Preferably, the total weight content of allulose, fructose and water of the aqueous allulose syrup provided in step (a) is at least 65 wt-%; more preferably at least 70 wt-%, still more preferably at least 75 wt-%, yet more preferably at least 80 wt-%, even more preferably at least 85 wt-%, and most preferably at least 90 wt-%; relative to the total weight of the aqueous allulose symp.
[0102] Preferably, the aqueous allulose syrup essentially consists of allulose, fructose, glucose, sucrose and water. Preferably, the total weight content of allulose, fructose, glucose, sucrose and water of the aqueous allulose syrup provided in step (a) is at least 95 wt-%; preferably at least 96 wt-%, preferably at least 97 wt-%, preferably at least 98 wt-%, preferably at least 99 wt-%, preferably at least 99.5 wt-%; relative to the total weight of the aqueous allulose syrup.
[0103] Preferably, the aqueous allulose syrup essentially consists of allulose, fructose and water. Preferably, the total weight content of allulose, fructose and water of the aqueous allulose syrup provided in step (a) is at least 95 wt-%; preferably at least 96 wt-%, preferably at least 97 wt-%, preferably at least 98 wt-%, preferably at least 99 wt-%, preferably at least 99.5 wt-%; relative to the total weight of the aqueous allulose symp.
[0104] Preferably, the aqueous allulose syrup essentially contains essentially neither glucose nor sucrose. It is contemplated, however, that the aqueous allulose syrup may preferably contain up to 1.0 wt-% glucose, more preferably up to 0.5 wt-% glucose, relative to the total weight of the aqueous allulose syrup.
[0105] The aqueous allulose syrup provided in step (a) may be obtained by any one of the various methods for the preparation of allulose syrups that are known from the prior art. In this regard, reference is made to e.g. US
2018 049458, US 2018 255814, WO 2019 083069, WO 2019 088654, US 2019 029299, US 2019 297931, US
2019 328014, US 2020 085090, which are incorporated herein by reference.
[0106] Preferably, the aqueous allulose syrup provided in step (a) has an allulose content (D-allulose) of at least 20 wt-%, preferably at least 22.5 wt-%, preferably at least 25 wt-%, preferably at least 27.5 wt-%, preferably at least 30 wt-%, preferably at least 32.5 wt-%, preferably at least 35 wt-%, preferably at least 37.5 wt-%, preferably at least 40 wt-%, preferably at least 42.5 wt-%, preferably at least 45 wt-%, preferably at least 47.5 wt-%; relative to the total weight of the aqueous allulose syrup.
[0107] Preferably, the aqueous allulose syrup provided in step (a) has an allulose content (D-allulose) of at least 50 wt-%, preferably at least 51 wt-%, preferably at least 52 wt-%, preferably at least 53 wt-%, preferably at least 54 wt-%, preferably at least 55 wt-%, preferably at least 56 wt-%, preferably at least 57 wt-%, preferably at least 58 wt-%, preferably at least 59 wt-%, preferably at least 60 wt-%, preferably at least 61 wt-%, preferably at least 62 wt-%, preferably at least 63 wt-%, preferably at least 64 wt-%, preferably at least 65 wt-%, preferably at least 66 wt-%, preferably at least 67 wt-%, preferably at least 68 wt-%, preferably at least 69 wt-%; relative to the total weight of the aqueous allulose symp.
[0108] Preferably, the aqueous allulose syrup provided in step (a) has an allulose content (D-allulose) of at least 65 wt-%, preferably at least 66 wt-%, preferably at least 67 wt-%, preferably at least 68 wt-%, preferably at least 69 wt-%, preferably at least 70 wt-%, preferably at least 71 wt-%, preferably at least 72 wt-%, preferably at least
73 wt-%, preferably at least 74 wt-%, preferably at least 75 wt-%, preferably at least 76 wt-%, preferably at least
77 wt-%, preferably at least 78 wt-%, preferably at least 79 wt-%, preferably at least 80 wt-%, preferably at least
81 wt-%, preferably at least 82 wt-%, preferably at least 83 wt-%, preferably at least 84 wt-%, preferably at least
85 wt-%, preferably at least 86 wt-%, preferably at least 87 wt-%, preferably at least 88 wt-%, preferably at least
89 wt-%, preferably at least 90 wt-%; relative to the total weight of the aqueous allulose syrup.
[0109] Preferably, the aqueous allulose syrup provided in step (a) has an allulose content of at least 61 wt-%, preferably at least 65 wt-%, more preferably at least 69 wt-%, still more preferably at least 73 wt-%, yet more preferably at least 77 wt-%, even more preferably at least 81 wt-%, most preferably at least 85 wt-%, and in particular at least 89 wt-%, relative to the total weight of the aqueous allulose symp.
[0110] It has been surprisingly found that when the aqueous allulose syrup provided in step (a) has an elevated pH value, it can advantageously be employed as starting material in the process according to the invention.
[0111] Preferably, the aqueous allulose syrup provided in step (a) has a pH value of at least 3.5, preferably at least 4.0, preferably at least 4.5, preferably at least 4.6, preferably at least 4.7, preferably at least 4.8, preferably at least 4.9, preferably at least 5.0, preferably at least 5.1, preferably at least 5.2, preferably at least 5.3, preferably at least 5.4, preferably at least 5.5, preferably at least 5.6, preferably at least 5.7, preferably at least 5.8, preferably at least 5.9, preferably at least 6.0.
[0112] Preferably, the aqueous allulose syrup provided in step (a) has a pH value of at least 4.0, more preferably at least 4.5, still more preferably at least 4.7, yet more preferably at least 5.0, even more preferably at least 5.2, most preferably at least 5.5, and in particular at least 5.7.
[0113] In preferred embodiments, the aqueous allulose symp provided in step (a) has a pH value within the range of 6.0±4.0, preferably 6.0±3.5, more preferably 6.0±3.0, still more preferably 6.0±2.5, yet more preferably 6.0±2.0, even more preferably 6.0±1.5, most preferably 6.0±1.0, and in particular 6.0±0.5.
[0114] In other preferred embodiments, the aqueous allulose syrup provided in step (a) has a pH value within the range of 7.0±4.0, preferably 7.0±3.5, more preferably 7.0±3.0, still more preferably 7.0±2.5, yet more preferably 7.0±2.0, even more preferably 7.0±1.5, most preferably 7.0±1.0, and in particular 7.0±0.5.
[0115] In further preferred embodiments, the aqueous allulose syrup provided in step (a) has a pH value within the range of 8.0±4.0, preferably 8.0±3.5, more preferably 8.0±3.0, still more preferably 8.0±2.5, yet more preferably 8.0±2.0, even more preferably 8.0±1.5, most preferably 8.0±1.0, and in particular 8.0±0.5.
[0116] The solubility of allulose in water increases with increasing temperature. Therefore, when the allulose content of the aqueous allulose syrup is above the threshold concentration at which allulose would spontaneously crystallize from aqueous solution at room temperature (oversaturation), the aqueous allulose syrup is preferably provided at a temperature above room temperature.
[0117] Preferably, the aqueous allulose syrup provided in step (a) has a water content of at least 2.5 wt-%; preferably at least 5.0 wt.-%, more preferably at least 7.5 wt-%, still more preferably at least 10 wt-%, yet more preferably at least 12.5 wt-%, even more preferably at least 15 wt-%, most preferably at least 17.5 wt-%, and in particular at least 20 wt-%; relative to the total weight of the aqueous allulose syrup. [0118] Preferably, the aqueous allulose syrup provided in step (a) has a water content of at most 80 wt.-%; preferably at most 70 wt-%, more preferably at most 60 wt-%, still more preferably at most 50 wt-%, yet more preferably at most 40 wt-%, even more preferably at most 30 wt-%, most preferably at most 20 wt-%, and in particular at most 10 wt-%; relative to the total weight of the aqueous allulose syrup.
[0119] Preferably, the aqueous allulose syrup provided in step (a) has a water content within the range of 70±30 wt-%; preferably 70±25 wt-%, more preferably 80±20 wt-%, still more preferably 80±15 wt-%, yet more preferably 85±15 wt-%, even more preferably 85±10 wt-%, most 90±10 wt-%, and in particular 95±5.0 wt-%; relative to the total weight of the aqueous allulose symp.
[0120] Preferably, the aqueous allulose syrup provided in step (a) has a total content of carbohydrates other than allulose and fructose of at most 5.0 wt-%; preferably at most 4.0 wt-%, preferably at most 3.0 wt-%, preferably at most 2.0 wt-%, preferably at most 1.0 wt-%; relative to the total content of all carbohydrates that are contained in the aqueous allulose symp.
[0121] Preferably, the aqueous allulose syrup provided in step (a) has a total content of glucose of at most 5.0 wt-%; preferably at most 4.0 wt-%, preferably at most 3.0 wt-%, preferably at most 2.0 wt-%, preferably at most 1.0 wt-%; relative to the total content of all carbohydrates that are contained in the aqueous allulose syrup.
[0122] Preferably, the aqueous allulose syrup provided in step (a) has a total content of sucrose of at most 3.0 wt-%; preferably at most 2.5 wt-%, preferably at most 2.0 wt-%, preferably at most 1.5 wt-%, preferably at most 1.0 wt-%; relative to the total content of all carbohydrates that are contained in the aqueous allulose symp.
[0123] Preferably, the process according to the invention is implemented as an integral part in an overall process for the production of a particulate allulose composition encompassing one or more preceding steps selected from the group consisting of
(ai) synthesizing allulose in a reactor; preferably from fructose; preferably under enzymatic catalysis;
(a2) withdrawing the product composition containing the synthesized allulose from the reactor;
(as) desalting the product composition;
(a4) decoloring the product composition;
(as) purifying the synthesized allulose that is contained in the product composition; preferably by chromatography;
(ae) filtrating the product compositions; preferably by nanofiltration or sterile filtration, more preferably sterile filtration;
(a?) concentrating the product composition; preferably (i) by evaporating water at elevated temperature and/or under reduced pressure and/or (ii) by reverse osmosis; and
(as) decoloring the concentrated product composition.
[0124] As one or more of the above preceding steps are performed at elevated temperatures, i.e. above room temperature (23 °C), the aqueous composition thus processed preferably is the aqueous allulose syrup that is provided in step (a) according to the invention. Thus, the heat supplied to the aqueous allulose syrup in the course of any one of the above preceding steps and the resultant elevated temperature of the aqueous allulose syrup is preferably used upon commencement of the process according to the invention. In other words, the aqueous allulose syrup that is obtained by any one of the above proceeding steps has preferably an elevated temperature anyway and is preferably not allowed to cool down to room temperature but is supplied to step (a) of the process according to the invention.
[0125] In preferred embodiments, step (a) of the process according to the invention, preferably the entire process, does not include preceding step (as) desalting the product composition.
[0126] In preferred embodiments, step (a) of the process according to the invention, preferably the entire process, does not include preceding step (a4) decoloring the product composition.
[0127] In preferred embodiments, step (a) of the process according to the invention, preferably the entire process, does not include preceding step (as) purifying the synthesized allulose that is contained in the product composition; preferably by chromatography.
[0128] In preferred embodiments, step (a) of the process according to the invention, preferably the entire process, does not include preceding step (a«) filtrating the product compositions; preferably by nanofiltration or sterile filtration, more preferably sterile filtration.
[0129] The process according to the invention can be advantageously implemented as an integral part into an overall process for the production of a particulate allulose composition, especially the preceding step (a?) of concentrating the product composition. This preceding step can be performed until the desired allulose concentration is reached in the aqueous allulose syrup. The given elevated temperature of the aqueous allulose symp is preferably maintained, and subsequently the thus heated aqueous allulose syrup can be further processed in the process according to the invention.
[0130] Preferably, the aqueous allulose syrup provided in step (a) additionally comprises fructose (D-fmctose).
[0131] Preferably, the content of fructose is at most 9.0 wt-%, preferably at most 8.0 wt-%, more preferably at most 7.0 wt-%, still more preferably at most 6.0 wt-%, yet more preferably at most 5.0 wt-%, even preferably at most 4.5 wt-%, most preferably at most 4.0 wt-%, and in particular at most 3.5 wt-%, relative to the dry solids content of the allulose syrup.
[0132] Preferably, the aqueous allulose syrup provided in step (a) additionally comprises glucose (D-glucose).
[0133] Preferably, the content of glucose is at most 7.0 wt-%, preferably at most 6.0 wt-%, more preferably at most 5.0 wt-%, still more preferably at most 4.0 wt-%, yet more preferably at most 3.0 wt-%, even preferably at most 2.5 wt-%, most preferably at most 2.3 wt-%, and in particular at most 2.0 wt-%, relative to the dry solids content of the allulose syrup.
[0134] Preferably, the aqueous allulose syrup provided in step (a) additionally comprises sucrose.
[0135] Preferably, the content of sucrose is at most 3.0 wt-%, preferably at most 2.5 wt-%, more preferably at most 2.0 wt-%, still more preferably at most 1.8 wt-%, yet more preferably at most 1.5 wt-%, even preferably at most 1.3 wt-%, most preferably at most 1.0 wt-%, and in particular at most 0.8 wt-%, relative to the dry solids content of the allulose symp. [0136] Typically, the aqueous allulose syrup provided in step (a) additionally comprises hydroxymethyl furfural (HMF).
[0137] Preferably, the content of hydroxymethyl furfural (HMF) is at most 1000 ppm, preferably at most 500 ppm, more preferably at most 200 ppm, relative to the dry solids content of the allulose syrup.
[0138] Preferably, the aqueous allulose syrup provided in step (a) essentially consists of allulose, water, fructose and optionally hydroxymethyl furfural (HMF).
[0139] Preferably, the purity of the allulose comprised in the aqueous allulose syrup provided in step (a) is at least 91.0 wt-%, preferably at least 92.0 wt-%, more preferably at least 93.0 wt-%, still more preferably at least 94.0 wt-%, yet more preferably at least 95.0 wt-%, even more preferably at least 95.5 wt-%, most preferably at least 96.0 wt-%, and in particular at least 96.5 wt-%, relative to the dry solids content of the allulose symp.
[0140] Step (b)
[0141] In step (b) of the process according to the invention, water is evaporated from the allulose syrup at a first temperature thereby obtaining an concentrated composition (evaporated composition) having a dry solids content of at least 90.0 wt-%, relative to the total weight of the concentrated composition.
[0142] Preferably, the concentrated composition obtained in step (b) has a dry solids content of at least 91.0 wt- %, preferably at least 92.0 wt-%, more preferably at least 93.0 wt-%, still more preferably at least 94.0 wt-%, yet more preferably at least 94.5 wt-%, even more preferably at least 95.0 wt-%, most preferably at least 95.5 wt-%, and in particular at least 96.0 wt-%, relative to the total weight of the concentrated composition.
[0143] Preferably, the concentrated composition obtained in step (b) has a dry solids content of at most 99.5 wt- %, preferably at most 99.0 wt-%, more preferably at most 98.5 wt-%, still more preferably at most 98.0 wt-%, yet more preferably at most 97.5 wt-%, even more preferably at most 97.0 wt-%, most preferably at most 96.5 wt-%, and in particular at most 96 wt-%, relative to the total weight of the concentrated composition.
[0144] Preferably, the concentrated composition obtained in step (b) has a dry solids content within the range of 96.0±2.0 wt-%, preferably 96.0±1.5 wt-%, more preferably 95.5 to 97.0 wt-%, still more preferably 96.0±1.0 wt-%, yet more preferably 96.0±0.5 wt-%, even more preferably 96.0 to 96.5 wt-%, relative to the total weight of the concentrated composition.
[0145] The concentrated composition obtained in step (b) is typically highly oversaturated. The concentrated composition typically has a state where spontaneous crystallization of allulose is principally possible for thermodynamic reasons, but is kinetically impeded. The dry solids content of the concentrated composition is typically significantly higher than that of mother liquors that are conventionally used for crystallization of allulose.
[0146] Preferably, the concentrated composition obtained in step (b) has a water content of at least 1.5 wt-%; preferably at least 2.0 wt-%, more preferably at least 2.5 wt-%, still more preferably at least 3.0 wt-%, yet more preferably at least 3.5 wt-%, even more preferably at least 4.0 wt-%, most preferably at least 4.5 wt-%, and in particular at least 5.0 wt-%; relative to the total weight of the concentrated composition.
[0147] Preferably, the concentrated composition obtained in step (b) has a water content of at most 10 wt-%; preferably at most 9.5 wt-%, more preferably at most 9.0 wt-%, still more preferably at most 8.5 wt-%, yet more preferably at most 8.0 wt.-%, even more preferably at most 7.5 wt.-%, most preferably at most 7.0 wt.-%, and in particular at most 6.5 wt-%; relative to the total weight of the concentrated composition.
[0148] Preferably, the concentrated composition obtained in step (b) has a water content within the range of 4.0±1.6 wt.-%; preferably 4.0±1.4 wt.-%, more preferably 4.0±1.2 wt.-%, still more preferably 4.0±1.0 wt.-%, yet more preferably 4.0±0.8 wt.-%, even more preferably 4.0±0.6 wt.-%, most preferably 4.0±0.4 wt.-%, and in particular 4.0±0.2 wt-%; relative to the total weight of the concentrated composition.
[0149] Preferably, the concentrated composition obtained in step (b) has a water content, relative to the total weight of the concentrated composition, that is below the water content of the aqueous allulose syrup that is provided in step (a), relative to the total weight of the aqueous allulose syrup that is provided in step (a), whereas the relative difference is at least -2.5 wt-%, preferably at least -5.0 wt-%, more preferably at least -7.5 wt-%, still more preferably at least -10 wt-%, yet more preferably at least -12.5 wt-%, even more preferably at least -15 wt- %, most preferably at least -17.5 wt-%, and in particular at least -20 wt-%.
[0150] Preferably, the concentrated composition obtained in step (b) has an allulose content of at least 90 wt-%, preferably at least 91 wt-%, preferably at least 92 wt-%, preferably at least 93 wt-%, preferably at least 94 wt- %, preferably at least 95 wt-%; relative to the total weight of the concentrated composition.
[0151] Preferably, the concentrated composition obtained in step (b) has an allulose content, relative to the total weight of the concentrated composition, that is greater than the allulose content of the aqueous allulose syrup that is provided in step (a), relative to the total weight of the aqueous allulose syrup that is provided in step (a), whereas the relative difference is at least 2.5 wt.-%, preferably at least 5.0 wt.-%, more preferably at least 7.5 wt.-%, still more preferably at least 10 wt.-%, yet more preferably at least 12.5 wt.-%, even more preferably at least 15 wt- %, most preferably at least 17.5 wt-%, and in particular at least 20 wt-%.
[0152] Preferably, in step (b) the first temperature is at least 35 °C; preferably at least 40 °C, more preferably at least 43 °C, still more preferably at least 46 °C, yet more preferably at least 49 °C, even more preferably at least 52 °C, most preferably at least 55 °C, and in particular at least 58 °C.
[0153] Preferably, in step (b) the first temperature is at most 70 °C; preferably at most 65 °C, more preferably at most 60 °C, still more preferably at most 57 °C, yet more preferably at most 54 °C, even more preferably at most 51 °C, most preferably at most 48 °C, and in particular at most 45 °C.
[0154] Preferably, in step (b) the first temperature is within the range of 53±20 °C; preferably 53±15 °C, more preferably 53±12 °C, still more preferably 53±10 °C, yet more preferably 53±8.0 °C, even more preferably 53±6.0 °C, most preferably 53±4.0 °C, and in particular 53±3.0 °C.
[0155] Preferably, in step (b) the water is evaporated from the allulose syrup under reduced pressure.
[0156] Preferably, step (b) involves heating the allulose syrup thereby producing a gas phase containing water, wherein the gas phase has a gas pressure that is maintained below atmospheric pressure.
[0157] Preferably, the gas pressure in step (b) is at most 800 mbar; preferably at most 750 mbar, preferably at most 700 mbar, preferably at most 650 mbar, preferably at most 600 mbar, preferably almost 550 mbar, preferably at most 500 mbar, preferably at most 450 mbar, preferably at most 400 mbar, preferably at most 350 mbar, preferably at most 300 mbar, preferably at most 250 mbar, preferably at most 200 mbar, preferably at most 150 mbar, preferably at most 100 mbar, preferably at most 90 mbar, preferably at most 80 mbar, preferably at most 70 mbar, preferably at most 60 mbar, preferably at most 50 mbar, preferably at most 40 mbar, preferably at most 30 mbar, preferably at most 20 mbar, preferably at most 10 mbar.
[0158] Preferably, the gas pressure in step (b) is at least 40 mbar; preferably at least 60 mbar, more preferably at least 80 mbar, still more preferably at least 100 mbar, yet more preferably at least 120 mbar, even more preferably at least 140 mbar, most preferably at least 160 mbar, and in particular at least 180 mbar.
[0159] Preferably, the gas pressure in step (b) is within the range of 450±400 mbar; preferably 400±350 mbar, more preferably 350±300 mbar, still more preferably 300±250 mbar, yet more preferably 250±200 mbar, even more preferably 200±150 mbar, most 150±100 mbar, and in particular 125±75 mbar.
[0160] Optionally, the pH value of the allulose syrup resulting from the evaporation of water in step (b) from the allulose syrup provided in step (a) is adjusted by the addition of an acidic additive or by the addition of a basic additive or by treatment of the allulose syrup resulting from the evaporation of water in step (b) from the allulose syrup provided in step (a) with an ion exchange resin to achieve a preferable pH value in the allulose symp resulting from the evaporation of water in step (b).
[0161] Preferably, the aqueous allulose syrup resulting from the evaporation of water in step (b) from the allulose syrup provided in step (a) is adjusted to a pH value of at least 3.5, preferably at least 4.0, preferably at least 4.5, preferably at least 4.6, preferably at least 4.7, preferably at least 4.8, preferably at least 4.9, preferably at least 5.0, preferably at least 5.1, preferably at least 5.2, preferably at least 5.3, preferably at least 5.4, preferably at least 5.5, preferably at least 5.6, preferably at least 5.7, preferably at least 5.8, preferably at least 5.9, preferably at least 6.0.
[0162] Preferably, the aqueous allulose syrup resulting from the evaporation of water in step (b) from the allulose syrup provided in step (a) is adjusted to a pH value of at least 4.0, more preferably at least 4.5, still more preferably at least 4.7, yet more preferably at least 5.0, even more preferably at least 5.2, most preferably at least 5.5, and in particular at least 5.7.
[0163] Optional step (c)
[0164] Preferably, in optional step (c) the aqueous allulose syrup to which seed crystals are added has a pH value of at least 4.0, more preferably at least 4.5, still more preferably at least 4.7, yet more preferably at least 5.0, even more preferably at least 5.2, most preferably at least 5.5, and in particular at least 5.7.
[0165] In optional step (c) of the process according to the invention, seed crystals of allulose are added to the concentrated composition thereby obtaining a seeded suspension.
[0166] Without wishing to be bound to any scientific theory, it appears that adding seed crystals to the highly oversaturated concentrated composition obtained in step (b) accelerates solidification of allulose in subsequent step (g).
[0167] Preferably, in step (c) the amount of seed crystals added to the concentrated composition is at least 3.0 wt-%; preferably at least 4.0 wt-%, more preferably at least 5.0 wt-%, still more preferably at least 6.0 wt-%, yet more preferably at least 7.0 wt-%, even more preferably at least 8.0 wt-%, most preferably at least 9.0 wt-%, and in particular at least 10 wt-%; relative to the total weight of the thus obtained seeded suspension.
[0168] Preferably, in step (c) the amount of seed crystals added to the concentrated composition is at most 24 wt-%; preferably at most 22 wt-%, more preferably at most 20 wt-%, still more preferably at most 18 wt-%, yet more preferably at most 16 wt-%, even more preferably at most 14 wt-%, most preferably at most 12 wt-%, and in particular at most 10 wt-%; relative to the total weight of the thus obtained seeded suspension.
[0169] Preferably, in step (c) the amount of seed crystals added to the concentrated composition is within the range of 10±8.0 wt-%; preferably 10±7.0 wt-%, more preferably 10±6.0 wt-%, still more preferably 10±5.0 wt- %, yet more preferably 10±4.0 wt-%, even more preferably 10±3.0 wt-%, most 10±2.0 wt-%, and in particular 10±1.0 wt-%; relative to the total weight of the thus obtained seeded suspension.
[0170] Preferably, the seed crystals added in step (c) have an average particle size of at least 12 pm, preferably at least 24 pm, more preferably at least 36 pm, still more preferably at least 48 pm, yet more preferably at least 75 pm, even more preferably at least 100 pm, most preferably at least 145 pm, and in particular at least 190 pm; preferably expressed as the geometric mean diameter (dg„) and preferably determined by sieving analysis, preferably in accordance with American Society of Agricultural and Biological Engineers (ASABE), ANSI/ASAE
S319.4 FEB2008 "Method of Determining and Expressing Fineness of Feed Materials by Sieving".
[0171] Preferably, the seed crystals added in step (c) have an average particle size of at most 190 pm, preferably at most 145 pm, more preferably at most 100 pm, still more preferably at most 75 pm, yet more preferably at most 48 pm, even more preferably at most 36 pm, most preferably at most 24 pm, and in particular at most 12 pm; preferably expressed as the geometric mean diameter (dg„) and preferably determined by sieving analysis, preferably in accordance with American Society of Agricultural and Biological Engineers (ASABE), ANSI/ASAE
S319.4 FEB2008 "Method of Determining and Expressing Fineness of Feed Materials by Sieving".
[0172] In preferred embodiments, the seed crystals added in step (c) have an average particle size within the range of 12±10 pm; preferably 12±8.0 pm, more preferably 12±7.0 pm, still more preferably 12±6.0 pm, yet more preferably 12±5.0 pm, even more preferably 12±4.0 pm, most 12±3.0 pm, and in particular 12±2.0 pm; preferably expressed as the geometric mean diameter (dgw) and preferably determined by sieving analysis, preferably in accordance with American Society of Agricultural and Biological Engineers (ASABE), ANSI/ASAE S319.4 FEB2008 "Method of Determining and Expressing Fineness of Feed Materials by Sieving" .
[0173] In further preferred embodiments, the seed crystals added in step (c) have an average particle size within the range of 36±24 pm; preferably 36±18 pm, more preferably 36±14 pm, still more preferably 36±10 pm, yet more preferably 36±8.0 pm, even more preferably 36±6.0 pm, most 36±4.0 pm, and in particular 36±2.0 pm; preferably expressed as the geometric mean diameter (dg„) and preferably determined by sieving analysis, preferably in accordance with American Society of Agricultural and Biological Engineers (ASABE), ANSI/ASAE
S319.4 FEB2008 "Method of Determining and Expressing Fineness of Feed Materials by Sieving".
[0174] In other preferred embodiments, the seed crystals added in step (c) have an average particle size within the range of 190±178 pm; preferably 190±154 pm, more preferably 190±96 pm, still more preferably 190±48 pm, yet more preferably 190±24 pm, even more preferably 190±12 pm, most 190±6.0 pm, and in particular 190±2.0 pm; preferably expressed as the geometric mean diameter (dgw) and preferably determined by sieving analysis, preferably in accordance with American Society of Agricultural and Biological Engineers (ASABE), ANSI/ASAE
S319.4 FEB2008 "Method of Determining and Expressing Fineness of Feed Materials by Sieving".
[0175] Optional step (d) [0176] In optional step (d) of the process according to the invention, the temperature of the seeded suspension is adjusted to a second temperature differing from the first temperature.
[0177] Preferably, in step (d) the second temperature is at least 24 °C; preferably at least 26 °C, more preferably at least 28 °C, still more preferably at least 30 °C, yet more preferably at least 32 °C, even more preferably at least 34 °C, most preferably at least 36 °C, and in particular at least 38 °C.
[0178] Preferably, in step (d) the second temperature is at most 56 °C; preferably at most 54 °C, more preferably at most 52 °C, still more preferably at most 50 °C, yet more preferably at most 48 °C, even more preferably at most 46 °C, most preferably at most 44 °C, and in particular at most 42 °C.
[0179] Preferably, in step (d) the second temperature is within the range of 40.0±9.0 °C; preferably 40.0±8.0 °C, more preferably 40.0±7.0 °C, still more preferably 40.0±6.0 °C, yet more preferably 40.0±5.0 °C (i.e. 35.0 to 45.0 °C), even more preferably 40.0±4.0 °C, most preferably 40.0±3.0 °C (i.e. 37.0 to 43.0 °C), and in particular 40.0±2.0 °C (i.e. 38.0 to 42.0 °C).
[0180] Optional step (e)
[0181] In optional step (e) of the process according to the invention, mechanical energy is introduced into the seeded suspension thereby obtaining a viscous composition.
[0182] Without wishing to be bound to any scientific theory, introducing mechanical energy into the seeded suspension greatly facilitates solidification in subsequent step (g). When step (e) is omitted and no mechanical energy is introduced, solidification in subsequent step (g) does not occur or at least requires significantly extended periods of time in spite of the presence of seed crystals.
[0183] The means for introducing mechanical energy in accordance with the invention are not particularly limited and include extruder, stirrer, and the like.
[0184] In preferred embodiments, in step (e) the mechanical energy is introduced without an extruder.
[0185] In other preferred embodiments, in step (e) the mechanical energy is introduced with an extruder.
[0186] The introduction of mechanical energy by an extmder is typically realized by a screw element inside the extruder that introduces high shearing forces when the extmder operates. A typical screw element inside the extruder that introduces high shearing forces when the extruder operates are kneading elements, e.g. kneading disks, kneading blocks, reverse screw elements, or the like, or combinations thereof. Such kneading elements are commercially available.
[0187] In other preferred embodiments, in step (e) the mechanical energy is introduced by means of an extruder.
[0188] Preferably, the seeded suspension is fed into an extmder. In general, extruders according to the invention are typically equipped with an inlet for feeding the starting material to be extruded into the extruder, and an outlet for withdrawing the extruded material from the extruder.
[0189] It is also contemplated that the seed crystals are added in step (c) to the concentrated composition in the course of extrusion. Thus, it is also contemplated that the concentrated composition is fed into the extruder, seed crystals are added through a suitable inlet on the extruder thereby rendering the concentrated composition a seeded suspension while it is being extruded. Thus, steps (c) and (e) of the process according to the invention, and additionally also step (d) of the process according to the invention, may be performed partially or fully simultaneously. [0190] Commercial extruders are typically equipped with a feeding device (feeding module) for supply of material to be extruded, i.e. the feeding device is located at the extruder inlet. As according to the invention the seeded suspension is fed into the extruder in a liquid state containing the suspended seed crystals, the feeding device of the extruder is preferably adapted for receiving liquid or semi-liquid materials.
[0191] The extruder type is not particularly limited. Preferably, the extruder is a single screw extruder, twin screw extruder or planetary roller extruder (planetary gear extruder). Extruders of this type are known to the skilled person and commercially available. Various extruders are known to the skilled person that include both the combination with similar or other extruders as well as the sectional combination of different extruder systems in one extruder. The combination of extruder sections of the same system is likewise included. In other words, the term "extruder" as used herein refers to various types and designs of extruders, including modular, sectional, integral, in series, or otherwise.
[0192] In preferred embodiments, the extruder is a single screw extruder.
[0193] In preferred embodiments, the extruder is a twin screw extruder with contrarotating screw configuration or corotating screw configuration.
[0194] In other preferred embodiments, the extruder is a planetary roller extruder. Typically, planetary roller extruders are equipped with a number of planetary spindles rotating around a central spindle. The planetary spindles, like the central spindle, have a toothing, usually a helical toothing, in one possible exemplification in the form of an involute toothing.
[0195] The extruder housing of a planetary roller extruder may internally also be toothed, in one possible exemplification equipped with a toothed liner. The planetary spindles intermesh with both the central spindle and the extruder housing or the liner. Under the flank pressure of the toothing, the planetary spindles would be moved outwards in an axial direction if the axial pressure were not absorbed by a thrust bearing or a thrust ring. Conventional extruders preferably have the thrust ring at the end of the housing, such that the thrust ring is put in place when the associated housing is clamped/screwed with its above-described flange. The thrust ring preferably surrounds the central spindle with a greater or lesser interspace. The feedstock processed or treated in the planetary roller extruder, i.e. the allulose composition being extruded, is conveyed through the gap between thrust ring and central spindle.
[0196] Preferably, some extrusion units of planetary roller extruders have such planetary roller extruder sections. Each planetary roller extruder section has a central spindle, a housing, planetary spindles rotating on the central spindle and in the internally toothed housing. At the same time the thrust rings prevent, restrict, and/or minimize the planetary spindles from moving in the axial direction out of the housing. In this regard, the planetary spindles slide on or against the thrust rings. The thrust rings are held between the ends of the housings of the various planetary roller extruder sections. Between the thrust rings and the central spindle there typically is a gap, through which the feedstock, i.e. the allulose composition being extruded, from one extruder section passes into the next. A common central spindle is preferably provided for the planetary roller extruder sections. The formation of a gap between the thrust ring and the central spindle is beneficial if no toothing on the central spindle is provided in the gap. Some planetary roller extruders have various planetary roller extruder sections, whereas preferably a common central spindle extends through the sections (see e.g. US 2018 281 263). [0197] Preferably, the extruder is equipped with a degassing section. Planetary roller extruders that are equipped with a degassing section are described e.g. in US 2020 001 502.
[0198] The extruder is preferably fitted with a barrel that can be heated to maintain the selected barrel temperature. The extruder outlet can also be fitted with a die face cutter to cut the extrudate into desired lengths.
[0199] Preferably, the extruder has an extrusion chamber in which extmsion is performed over a length of 3.0±2.5 m, more preferably 3.0±2.0 m, still more preferably 3.0±1.5 m, yet more preferably 3.0±1.0 m, even more preferably 3.0±0.5 m.
[0200] Preferably, extrusion conditions are optimized with respect to shearing forces, use of specific transport elements, and/or use of specific back-mixing elements. These measures and elements are known to a skilled person. With respect to back-mixing elements reference is made to e.g. EP 0 919 127 Al which is incorporated by reference. In an adjoining back-mixing zone, the extmder shafts have back-mixing elements or backward-acting screw sections with openings for the extruded mass to pass through during its forward transport movement. In the back-mixing zone, the extruded mass is particularly intimately mixed, which leads to an even distribution of air in the extruded mass.
[0201] Preferably, the extmder is equipped with kneading elements.
[0202] Preferably, the extruder is equipped with transport elements.
[0203] Preferably, the extruder is equipped with a screw or two screws each having a length to diameter ratio (L/D) within the range of from 5 to 50; preferably 10 to 40, or 15 to 35, or 20 to 30.
[0204] Preferably, the seeded suspension that is fed into the extruder has a temperature of at least 35°C; preferably at least 40°C, more preferably at least 43 °C, still more preferably at least 46°C, yet more preferably at least 49°C, even more preferably at least 52°C, most preferably at least 55°C, and in particular at least 58°C.
[0205] Preferably, the seeded suspension that is fed into the extruder has a temperature of at most 70°C; preferably at most 65°C, more preferably at most 60°C, still more preferably at most 57°C, yet more preferably at most 54°C, even more preferably at most 51 °C, most preferably at most 48°C, and in particular at most 45°C
[0206] Preferably, the seeded suspension that is fed into the extruder in step (c) has a temperature within the range of 53±20°C; preferably 53±15°C, more preferably 53±12°C, still more preferably 53±10°C, yet more preferably 53±8.0°C, even more preferably 53±6.0°C, most 53±4.0°C, and in particular 53±3.0°C.
[0207] Preferably, the extrusion temperature is within the range of from 50 to 60°C, wherein the seeded suspension having a temperature within the range of from 50 to 60°C is conveyed in the extruder, preferably without supplying additional heat by means of heating elements, whereas due to dissipation of heat the temperature of the composition at the extruder outlet may be lower than the temperature at the extruder inlet, whereas the temperature of the composition at the extruder outlet is preferably also within the range of from 50 to 60°C.
[0208] In preferred embodiments, extrusion is performed under evaporative conditions and serves the purpose of drying the feed stock, i.e. the seeded suspension. According to these preferred embodiments, the extruder is capable of being used for extrusion drying, preferably heated extrusion drying.
[0209] For the purpose of the specification, extrusion under "evaporative conditions" are preferably conditions where evolved vapor, especially water vapor, is withdrawn from the extruder. [0210] Heated extrusion drying is typically done by preferably continuously feeding the seeded suspension to be dried into an inlet of an extruder fitted with a heated barrel and continuously collecting the dried material as it exits the extruder. The heated barrel of an extrusion drier heats the contents of the extruder to volatilize water contained in the material to be dried. The extruder barrel can be vented to allow the escape of water vapor.
[0211] Preferably, the seeded suspension is subjected to shearing forces in the extruder. In preferred embodiments, the seeded suspension is dried in the extruder under evaporative conditions.
[0212] Preferably, the extruder is operated in horizontal arrangement.
[0213] Preferably, the extruder is operated at an elevated extrusion temperature.
[0214] Preferably, the elevated extrusion temperature is at least 30°C; preferably at least 31°C, preferably atleast 32°C, preferably at least 33°C, preferably at least 34°C, preferably at least 35°C, preferably at least 36°C, preferably at least 37°C, preferably at least 38°C, preferably at least 39°C, preferably at least 40°C, preferably at least 41°C, preferably at least 42°C, preferably at least 43°C, preferably at least 44°C, preferably at least 45°C, preferably at least 46°C, preferably at least 47°C, preferably at least 48°C, preferably at least 49°C, preferably at least 50°C, preferably at least 51°C, preferably at least 52°C, preferably at least 53°C, preferably at least 54°C, preferably at least 55°C, preferably at least 56°C, preferably at least 57°C, preferably at least 58°C, preferably at least 59°C, preferably at least 60°C.
[0215] Preferably, the elevated extmsion temperature is at most 80°C; preferably at most 79°C, preferably at most 78°C, preferably at most 77°C, preferably at most 76°C, preferably at most 75°C, preferably at most 74°C, preferably at most 73°C, preferably at most 72°C, preferably at most 71°C, preferably at most 70°C, preferably at most 69°C, preferably at most 68°C, preferably at most 67°C, preferably at most 66°C, preferably at most 65°C, preferably at most 64°C, preferably at most 63 °C, preferably at most 62°C, preferably at most 61 °C, preferably at most 60°C, preferably at most 59°C, preferably at most 58°C, preferably at most 57°C, preferably at most 56°C, preferably at most 55°C, preferably at most 54°C, preferably at most 53°C, preferably at most 52°C, preferably at most 51°C, preferably at most 50°C.
[0216] Preferably, the elevated extrusion temperature is at least 35°C; preferably at least 40°C, more preferably at least 43 °C, still more preferably at least 46°C, yet more preferably at least 49°C, even more preferably at least 52°C, most preferably at least 55°C, and in particular at least 58°C.
[0217] Preferably, the elevated extrusion temperature is at most 70°C; preferably at most 65°C, more preferably at most 60°C, still more preferably at most 57°C, yet more preferably at most 54°C, even more preferably at most 51°C, most preferably at most 48°C, and in particular at most 45°C.
[0218] Preferably, the elevated extrusion temperature is within the range of 53±20°C; preferably 53±15°C, more preferably 53±12°C, still more preferably 53±10°C, yet more preferably 53±8.0°C, even more preferably 53±6.0°C, most 53±4.0°C, and in particular 53±3.0°C.
[0219] Preferably, the extrusion temperature is within the range of from 50 to 60°C, wherein the seeded suspension having a temperature within the range of from 50 to 60°C is conveyed in the extruder, preferably without supplying additional heat by means of heating elements, whereas due to dissipation of heat the temperature of the composition at the extruder outlet may be lower than the temperature at the extruder inlet, whereas the temperature of the composition at the extruder outlet is preferably also within the range of from 50 to 60°C. [0220] Preferably, the extruder comprises a first temperature zone operated at temperature Ti, in direction of extrusion followed by a second temperature zone operated at temperature T2, wherein Tl > T2, or T2 > Tl.
[0221] Preferably, the extmder comprises a first temperature zone operated at temperature Tl, in direction of extrusion followed by a second temperature zone operated at temperature T2, in direction of extrusion followed by a third temperature zone operated at temperature T3, wherein Tl > T2 > T3, or Ti > T3 > T2, or T2 > Tl > T3, or T2 > T3 > Tl, or T3 > Tl > T2, or T3 > T2 > Tl.
[0222] It is principally also contemplated that in certain embodiments the feedstock, i.e. the seeded suspension being extruded, may be cooled in the course of extrusion.
[0223] In preferred embodiment, the seeded suspension being extruded is cooled in the course of extrusion such that the temperature of the viscous composition that is withdrawn from the extruder has a temperature below the temperature of the seeded suspension that is fed into the extruder.
[0224] In preferred embodiments, the relative temperature difference between the temperature of the viscous composition that is withdrawn from the extruder compared to the temperature of the seeded suspension that is fed into the extruder is at least -1.0°C, more preferably at least -2.0°C, still more preferably at least -3.0°C, yet more preferably at least -4.0°C, even more preferably at least -5.0°C, most preferably at least -6.0°C, and in particular at least -7.0°C.
[0225] In preferred embodiments, the relative temperature difference between the temperature of the viscous composition that is withdrawn from the extruder compared to the temperature of the seeded suspension that is fed into the extruder is at least -8.0°C, more preferably at least -9.0°C, still more preferably at least -10°C, yet more preferably at least -12°C, even more preferably at least -14°C, most preferably at least -16°C, and in particular at least -18°C.
[0226] Extrusion preferably takes place in an extmder in which the feedstock, i.e. the mass to be extruded, is pressed through a die. The hole diameter of the die determines the particle diameter.
[0227] Preferably, the hole diameter of the die is at least 0.1 mm; preferably at least 0.2 mm, preferably at least 0.3 mm, preferably at least 0.4 mm. Preferably, the hole diameter of the die is at most 2.0 mm; preferably at most 1.8 mm, preferably at most 1.6 mm, preferably at most 1.4 mm, preferably at most 1.2 mm, preferably at most 1.0 mm. Preferably, the hole diameter of the die is in the range from 0.3 to 2 mm and in particular in the range from 0.4 to 1.0 mm.
[0228] Preferably, in the course of extrusion the seeded suspension is exerted in the extmder to an increased pressure.
[0229] Preferably, the increased pressure is at least 1.5 bar; preferably at least 2.0 bar, preferably at least 2.5 bar, preferably at least 3.0 bar, preferably at least 3.5 bar, preferably at least 4.0 bar, preferably at least 4.5 bar, preferably at least 5.0 bar, preferably at least 6.0 bar, preferably at least 7.0 bar, preferably at least 8.0 bar, preferably at least 9.0 bar, preferably at least 10 bar.
[0230] Preferably, the mean residence time of the seeded suspension (viscous composition) in the extruder is at least 10 seconds; preferably at least 20 seconds, preferably at least 30 seconds, preferably at least 40 seconds, preferably at least 50 seconds, preferably at least 60 seconds, preferably at least 70 seconds, preferably at least 80 seconds, preferably at least 90 seconds, preferably at least 100 seconds, preferably at least 110 seconds, preferably at least 120 seconds.
[0231] Preferably, the mean residence time of the seeded suspension (viscous composition) in the extruder is at most 1000 seconds; preferably at most 950 seconds, preferably at most 900 seconds, preferably at most 850 seconds, preferably at most 800 seconds, preferably at most 750 seconds, preferably at most 700 seconds, preferably at most 650 seconds, preferably at most 600 seconds, preferably at most 550 seconds, preferably at most 500 seconds, preferably at most 450 seconds, preferably at most 400 seconds, preferably at most 350 seconds, preferably at most 300 seconds.
[0232] Preferably, the mean residence time of the seeded suspension (viscous composition) in the extruder is at least 2.0 seconds; preferably at least 4.0 seconds, more preferably at least 6.0 seconds, still more preferably at least 8.0 seconds, yet more preferably at least 10 seconds, even more preferably at least 15 seconds, most preferably at least 30 seconds, and in particular at least 60 seconds.
[0233] Preferably, the mean residence time of the seeded suspension (viscous composition) in the extruder is at most 1800 seconds; preferably at most 900 seconds, more preferably at most 600 seconds, still more preferably at most 540 seconds, yet more preferably at most 480 seconds, even more preferably at most 420 seconds, most preferably at most 360 seconds, and in particular at most 300 seconds.
[0234] Preferably, the mean residence time of the seeded suspension (viscous composition) in the extruder is within the range of 320±240 seconds; preferably 160±120 seconds, more preferably 80±60 seconds, still more preferably 40±30 seconds, yet more preferably 20±15 seconds, even more preferably 10±7.5 seconds, most7.5±5.0 seconds, and in particular 5.0±2.0 seconds.
[0235] In particularly preferred embodiments, the mean residence time of the seeded suspension (viscous composition) in the extruder is within the range of from 5 to 10 minutes, i.e. 300 to 600 seconds.
[0236] Preferably, the extruder is operated at a maximum torque of at least 10 Ncm; preferably at least 20 Ncm, preferably at least 30 Ncm, preferably at least 40 Ncm, preferably at least 50 Ncm, preferably at least 60 Ncm, preferably at least 70 Ncm, preferably at least 80 Ncm, preferably at least 90 Ncm, preferably at least 100 Ncm.
[0237] Preferably, the extruder is operated at a maximum torque of at least 10 Nm; preferably at least 20 Nm, preferably at least 30 Nm, preferably at least 40 Nm, preferably at least 50 Nm, preferably at least 60 Nm, preferably at least 70 Nm, preferably at least 80 Nm, preferably at least 90 Nm, preferably at least 100 Nm.
[0238] Preferably, the extruder is operated at a maximum torque of at most 200 Ncm; preferably at most 190 Ncm, preferably at most 180 Ncm, preferably at most 170 Ncm, preferably at most 160 Ncm, preferably at most 150 Nm, preferably at most 140 Ncm, preferably at most 120 Ncm.
[0239] Preferably, the extmder is operated at a maximum torque of at most 200 Nm; preferably at most 190 Nm, preferably at most 180 Nm, preferably at most 170 Nm, preferably at most 160 Nm, preferably at most 150 Nm, preferably at most 140 Nm, preferably at most 120 Nm.
[0240] Preferably, the extmder is operated at a rotational speed of at least 5 rpm; preferably at least 10 rpm, preferably at least 15 rpm, preferably at least 20 rpm, preferably at least 25 rpm, preferably at least 30 rpm, preferably at least 35 rpm, preferably at least 40 rpm, preferably at least 50 rpm. [0241] Preferably, the extruder is operated at a rotational speed of at most 200 rpm; preferably at most 190 rpm, preferably at most 180 rpm, preferably at most 170 rpm, preferably at most 160 rpm, preferably at most 150 rpm, preferably at most 140 rpm, preferably at most 130 rpm, preferably at most 120 rpm, preferably at most 110 rpm, preferably at most 100 rpm.
[0242] In preferred embodiments, the seeded suspension (viscous composition) is extruded in the extruder under non-evaporative conditions, i.e. the extrusion as such preferably does not significantly alter the water content or the allulose content of the seeded suspension being extruded. In this regard, it is contemplated that flash evaporation may occur after the extmded material has exited the extmder and that such flash evaporation may slightly reduce the water content or the allulose content of the seeded suspension (viscous composition) outside the extruder.
[0243] In other preferred embodiments, the seeded suspension (viscous composition) is dried in the extmder under evaporative conditions. Thus, in preferred embodiments, the seeded suspension is conveyed in the extruder containing allulose and a gas phase containing water, wherein the gas phase has a gas pressure that is maintained below atmospheric pressure.
[0244] Preferably, the gas pressure is at most 800 mbar; preferably at most 750 mbar, preferably at most 700 mbar, preferably at most 650 mbar, preferably at most 600 mbar, preferably at most 550 mbar, preferably at most 500 mbar, preferably at most 450 mbar, preferably at most 400 mbar, preferably at most 350 mbar, preferably at most 300 mbar, preferably at most 250 mbar, preferably at most 200 mbar, preferably almost 150 mbar, preferably at most 100 mbar, preferably at most 90 mbar, preferably at most 80 mbar, preferably at most 70 mbar, preferably at most 60 mbar, preferably at most 50 mbar, preferably at most 40 mbar, preferably at most 30 mbar, preferably at most 20 mbar, preferably at most 10 mbar.
[0245] Preferably, the gas pressure is at least 40 mbar; preferably at least 60 mbar, more preferably at least 80 mbar, still more preferably at least 100 mbar, yet more preferably at least 120 mbar, even more preferably at least 140 mbar, most preferably at least 160 mbar, and in particular at least 180 mbar.
[0246] Preferably, the gas pressure is at most 260 mbar; preferably at most 230 mbar, more preferably at most 200 mbar, still more preferably at most 170 mbar, yet more preferably at most 140 mbar, even more preferably at most 110 mbar, most preferably at most 80 mbar, and in particular at most 50 mbar.
[0247] Preferably, the gas pressure is within the range of 450±400 mbar; preferably 400±350 mbar, more preferably 350±300 mbar, still more preferably 300±250 mbar, yet more preferably 250±200 mbar, even more preferably 200±150 mbar, most 150±100 mbar, and in particular 125±75 mbar.
[0248] Preferably, extrusion involves expanding the allulose composition in a compressed state into a vaporized state thereby evaporating water from the allulose composition.
[0249] Preferably, at least a portion of the gas phase is separated from the allulose composition.
[0250] After extrusion, the viscous composition is obtained from the extruder.
[0251] It is also contemplated that the composition obtained from the extruder is a film. This can be achieved by using an extrusion die of appropriate shape and dimension. Thus, steps (e) and (f) of the process according to the invention may be performed partially or fully simultaneously. Preferred details of step (f) are described further below. [0252] It is also contemplated that the composition obtained from the extmder is already the solidified composition. Thus, it is contemplated that in the course of the extrusion process, within the extmder, the seeded suspension is converted into the viscous composition which in turn is converted into the solidified composition. Thus, steps (e) and (g) of the process according to the invention may be performed partially or fully simultaneously. Preferred details of step (g) are described further below.
[0253] The material exiting the outlet of the extruder is typically the viscous composition. However, it is also contemplated that solidifying takes place within the extruder such that it is already the solidified composition that exits the extruder in solid form, e.g. in form of a particulate material or powder. Alternatively, the composition exiting the exact ruder may be a viscous mass (viscous composition), e.g. an allulose suspension, an oversaturated allulose solution, or an allulose melt, that subsequently spontaneously solidifies in the course of exiting the outlet of the extruder or thereafter, optionally after cooling to room temperature and/or optionally after a certain period of time but preferably within not more than 72 hours (e.g. after-crystallization, post-crystallization).
[0254] Therefore, the composition obtained from the extruder in step (e) is preferably selected from (i) a solidified composition, (ii) a suspension, (iii) an oversaturated solution, and (iv) a melt.
[0255] When the composition obtained from the extruder is a solidified composition, it may exit the extruder in the form of a solidified extmsion strand of material or in the form of a particulate material. While the solidified composition may still have a significant water content, according to this embodiment the solidified composition preferably forms a single solid phase but no liquid phase. Depending upon the temperature, the solidified composition may be a viscous mass that further solidifies upon cooling. In such a state, the solidified composition may resemble a melt. A skilled person recognizes that upon heating, a solidified composition transforms into a melt, whereas melting may occur over a broad temperature range. Thus, there typically is no distinct temperature clearly discriminating a solidified composition from a melt. For the purpose of the specification, a melt is present when the temperature of the composition is above the melting point of pure crystalline allulose (96°C).
[0256] Alternatively, when the composition obtained from the extmder is a suspension, it forms a solid phase and a liquid phase, where solid particles are suspended in a liquid phase. For the purpose of the specification, a suspension may be any composition having a solid phase and a liquid phase, irrespective of whether the particles are finely suspended in the liquid phase forming a stable suspension or whether the particles precipitate and clearly separate from the liquid phase.
[0257] When the composition obtained from the extruder is an oversaturated solution, it still does not contain a significant amount of solidified material, but preferably is present in a highly instable state that preferably after cooling to room temperature (23 °C) has a pronounced tendency to spontaneously solidify.
[0258] When the composition obtained from the extruder is a melt, it forms a single phase but is present at a temperature above the melting point of pure crystalline allulose (96°C). When the melt is allowed to cool to room temperature (23 °C) it will typically convert into a solidified composition.
[0259] Preferably, the composition obtained from the extmder is liquid, semi-solid, or pasty. Preferably, the allulose content of the liquid, semi-solid, or pasty composition obtained from the extruder is higher than the allulose content of the seeded suspension fed into the extruder. Preferably, the water content of the liquid, semi-solid, or pasty composition obtained from the extmder is lower than the allulose content of the seeded suspension fed into the extruder. In this regard, it is contemplated that flash evaporation may occur after the extruded material has exited the extruder and that such flash evaporation may slightly reduce the water content or the allulose content of the composition outside the extruder.
[0260] Preferably, the composition solidifies completely, preferably precipitates and/or crystallizes after being obtained from the extruder. Preferably, the composition solidifies completely, preferably precipitates and/or crystallizes within a time of at most 76 hours, preferably at most 24 hours, more preferably at most 12 hours, still more preferably at most 60 minutes, yet more preferably at most 40 minutes, even more preferably at most 20 minutes, most preferably at most 15 minutes, and in particular at most 10 minutes.
[0261] When the seeded suspension (viscous composition) is dried in the extruder under evaporative conditions, vapor, especially water vapor, is withdrawn from the extruder thereby reducing the water content of the composition that is obtained from the extruder compared to the water content of the seeded suspension that is fed into the extruder.
[0262] Preferably, the composition obtained from the extruder has a water content, relative to the total weight of the composition, that is lower than the water content of the seeded suspension that is fed into the extruder, relative to the total weight of the seeded suspension that is fed into the extruder, whereas the relative difference is at least -2.5 wt.-%, preferably at least -5.0 wt-%, more preferably at least -7.5 wt-%, still more preferably at least -10 wt- %, yet more preferably at least -12.5 wt-%, even more preferably at least -15 wt-%, most preferably at least -17.5 wt-%, and in particular at least -20 wt-%.
[0263] Reducing the water content under evaporative conditions causes an increase of the allulose content relative to the total weight of the composition.
[0264] Preferably, the composition obtained from the extruder has an allulose content, relative to the total weight of the composition, that is greater than the allulose content of the seeded suspension that is fed into the extruder, relative to the total weight of the seeded suspension that is fed into the extruder, whereas the relative difference is at least 2.5 wt-%, preferably at least 5.0 wt-%, more preferably at least 7.5 wt-%, still more preferably at least 10 wt-%, yet more preferably at least 12.5 wt-%, even more preferably at least 15 wt-%, most preferably at least 17.5 wt-%, and in particular at least 20 wt-%.
[0265] Preferably, the evaporative conditions are adjusted such that the above relative differences in water content and allulose content, respectively, are achieved. A skilled person can easily determine suitable evaporative conditions by routine experimental tests varying temperature, pressure (vacuum) and residence time. A skilled person immediately recognizes that higher evaporation rates can be achieved at higher temperatures, lower pressures and/or extended residence times.
[0266] It is also contemplated that the composition obtained from the extruder is a particulate composition. Thus, steps (e), (g) and (h) of the process according to the invention may be performed partially or fully simultaneously. Preferred details of step (h) are described further below.
[0267] Preferably, the extruded feedstock strand, i.e. the composition leaving the extruder, breaks up into short granule-like particles or can likewise be broken with the help of suitable cutting devices. The granule particles obtained in this way preferably have a homogeneous grain size, i.e. a narrow grain size distribution.
[0268] In further preferred embodiments, in step (e) the mechanical energy is introduced by mixing or stirring. [0269] The mechanical energy is typically introduced by means of suitable devices, e.g. extruders, mixers or stirrers. It is possible that two or more of such devices are arranged in series, such that in a first partial step (ei) mechanical energy is introduced by means of a first device, e.g. first extruder, first mixer or first stirrer, and thereafter the thus treated suspension is fed into a second device, e.g. second extruder, second mixer or second stirrer, where in a second partial step (62) further mechanical energy is introduced by means of the second device.
[0270] The two or more devices that are arranged in series can be of the same type (e.g. extruder/extruder, mixer/mixer or stirrer/stirrer), or of different types (e.g. extruder/stirrer, extruder/mixer, stirrer/extruder, stir- rer/mixer, mixer/extruder or mixer/stirrer).
[0271] Preferably, in step (e) the mechanical energy is introduced by means of a stirrer; preferably but not limited to a stirrer selected from the group consisting of spiral stirrer, impeller stirrer, paddle stirrer, propeller stirrer, blade stirrer, oblique blade stirrer, pitched blade propeller stirrer, scroll paddle stirrer, paddle wheel stirrer, disc stirrer, butterfly stirrer, conical cup stirrer, guide rail stirrer, and anchor stirrer; preferably spiral stirrer.
[0272] In particularly preferred embodiments, in step (e) the mechanical energy is introduced by means of a pressure beater. Suitable pressure beaters were originally designed for the continuous aeration of sugar masses. The pressure beater is preferably equipped with a stator and a rotor which both carry elements (e.g. intermeshing shear pins) that introduce high shear forces when the rotor is rotated. The heart of such pressure beaters is the head, consisting of rotor and stator, which can preferably be tempered for heating and/or cooling. The elements (e.g. intermeshing shear pins) ensure intensive mixing. In addition to the main head, there is preferably also a small prerotor and pre-stator combination. The seeded suspension is metered into the pre-stator. The base compound is subsequently metered into the pressure system of the main stator and a homogeneous mixture is produced. Suitable devices are commercially available.
[0273] Preferably, in step (e) the mechanical energy is introduced by stirring at a rotation speed of at least 10 rpm, preferably at least 20 rpm, more preferably at least 30 rpm, still more preferably at least 40 rpm, yet more preferably at least 50 rpm, even more preferably at least 60 rpm, most preferably at least 70 rpm, and in particular at least 80 rpm.
[0274] Preferably, in step (e) the mechanical energy is introduced by stirring at a rotation speed of at least 90 rpm, preferably at least 100 rpm, more preferably at least 110 rpm, still more preferably at least 120 rpm, yet more preferably at least 130 rpm, even more preferably at least 140 rpm, most preferably at least 150 rpm, and in particular at least 160 rpm.
[0275] Preferably, in step (e) the mechanical energy is introduced by stirring at a torque of at least 20 Ncm, preferably at least 40 Ncm, more preferably at least 60 Ncm, still more preferably at least 80 Ncm, yet more preferably at least 100 Ncm, even more preferably at least 120 Ncm, most preferably at least 140 Ncm, and in particular at least 160 Ncm.
[0276] Preferably, in step (e) the mechanical energy is introduced by stirring at a torque of at least 20 Nm, preferably at least 40 Nm, more preferably at least 60 Nm, still more preferably at least 80 Nm, yet more preferably at least 100 Nm, even more preferably at least 120 Nm, most preferably at least 140 Nm, and in particular at least 160 Nm.
[0277] Preferably, step (e) is performed at atmospheric pressure. [0278] Preferably, step (e) is performed under adiabatic conditions.
[0279] Preferably, in the course of step (e) the temperature and/or the viscosity of the seeded suspension increases.
[0280] Preferably, step (e) is commenced at an initial temperature of the seeded suspension, preferably at the first temperature, more preferably at the second temperature, and wherein step (e) is terminated when the temperature of the seeded suspension has reached an end temperature which is higher than the initial temperature.
[0281] Preferably, the end temperature is relatively higher by at least 2.0 °C than the initial temperature, preferably by at least 4.0 °C, more preferably by at least 6.0 °C, still more preferably by at least 8.0 °C, yet more preferably by at least 10 °C, even more preferably by at least 12 °C, most preferably by at least 14 °C, and in particular by at least 16 °C.
[0282] Preferably, step (e) is commenced at an initial viscosity of the seeded suspension and wherein step (e) is terminated when the viscosity of the seeded suspension has reached an end viscosity which is higher than the initial viscosity.
[0283] Preferably, the value of the end viscosity is relatively higher by at least 200 mPa-s than the value of the initial viscosity, preferably by at least 400 mPa-s, more preferably by at least 600 mPa-s, still more preferably by at least 800 mPa-s, yet more preferably by at least 1000 mPa-s, even more preferably by at least 1200 mPa-s, most preferably by at least 1400 mPa-s, and in particular by at least 1600 mPa-s; wherein the initial viscosity is determined at the given temperature of the seeded suspension when step (e) is commenced (initial temperature) and the end viscosity is determined at the given temperature of the seeded suspension when step (e) is terminated (end temperature), preferably by means of a rotary viscosimeter according to ASTM-D2196.
[0284] Preferably, the value of the end viscosity is relatively higher by at least 20 Pa-s than the value of the initial viscosity, preferably by at least 40 Pa-s, more preferably by at least 60 Pa-s, still more preferably by at least 80 Pa-s, yet more preferably by at least 100 Pa-s, even more preferably by at least 120 Pa-s, most preferably by at least 140 Pa-s, and in particular by at least 160 Pa-s; wherein the initial viscosity is determined at the given temperature of the seeded suspension when step (e) is commenced (initial temperature) and the end viscosity is determined at the given temperature of the seeded suspension when step (e) is terminated (end temperature), preferably by means of a rotary viscosimeter according to ASTM-D2196.
[0285] Preferably, step (e) is commenced under conditions where an initial torque would be necessary in order to stir the seeded suspension at a rotational speed of 60 rpm at the given temperature of the seeded suspension when step (e) is commenced (initial temperature), and wherein step (e) is terminated under conditions where an end torque would be necessary in order to stir the seeded suspension at a rotational speed of 60 rpm at the given temperature of the seeded suspension when step (e) is terminated (end temperature), wherein the end torque is higher than the initial torque.
[0286] Preferably, the end torque is relatively higher by at least 2.0 Ncm than the initial torque, preferably by at least 4.0 Ncm, more preferably by at least 6.0 Ncm, still more preferably by at least 8.0 Ncm, yet more preferably by at least 10 Ncm, even more preferably by at least 12 Ncm, most preferably by at least 14 Ncm, and in particular by at least 16 Ncm. [0287] Preferably, the end torque is relatively higher by at least 2.0 Nm than the initial torque, preferably by at least 4.0 Nm, more preferably by at least 6.0 Nm, still more preferably by at least 8.0 Nm, yet more preferably by at least 10 Nm, even more preferably by at least 12 Nm, most preferably by at least 14 Nm, and in particular by at least 16 Nm.
[0288] Preferably, the end torque is relatively higher by at least 18 Ncm than the initial torque, preferably by at least 20 Ncm, more preferably by at least 22 Ncm, still more preferably by at least 24 Ncm, yet more preferably by at least 26 Ncm, even more preferably by at least 28 Ncm, most preferably by at least 30 Ncm, and in particular by at least 32 Ncm.
[0289] Preferably, the end torque is relatively higher by at least 18 Nm than the initial torque, preferably by at least 20 Nm, more preferably by at least 22 Nm, still more preferably by at least 24 Nm, yet more preferably by at least 26 Nm, even more preferably by at least 28 Nm, most preferably by at least 30 Nm, and in particular by at least 32 Nm.
[0290] Optional step (f)
[0291] In optional step (f) of the process according to the invention, the viscous composition is formed into a film.
[0292] Preferably, in step (f) the viscous composition is formed into a fdm having a thickness of at most 35 mm, preferably at most 30 mm, more preferably at most 25 mm, still more preferably at most 20 mm, yet more preferably at most 15 mm, even more preferably at most 10 mm, most preferably at most 5.0 mm, and in particular at most 2.5 mm.
[0293] Preferably, in step (f) the viscous composition is formed into a fdm having a thickness of at most 2.4 mm, preferably at most 2.3 mm, more preferably at most 2.2 mm, still more preferably at most 2.1 mm, yet more preferably almost 2.0 mm, even more preferably almost 1.9 mm, mo st preferably al most 1.8 mm, and in particular at most 1.7 mm.
[0294] Step (g)
[0295] In step (g) of the process according to the invention, the viscous composition is allowed to solidify thereby obtaining a solidified allulose composition.
[0296] Without wishing to be bound to any scientific theory, it appears that solidification in step (g) can be gready facilitated due to the presence of seed crystals in the seeded suspension, but especially also due to introducing mechanical energy in step (e). Solidification also occurs when no seed crystals are added and when no mechanical energy is introduced. Under these circumstances, however, solidification will typically require significantly more time as solidification is kinetically impeded.
[0297] Preferably, the viscous composition solidifies completely, preferably precipitates and/or crystallizes.
[0298] Preferably, step (g) is performed for at most 8.0 h, preferably at most 7.0 h, more preferably at most 6.0 h, still more preferably at most 5.0 h, yet more preferably at most 4.0 h, even more preferably at most 3.0 h, most preferably at most 2.0 h, and in particular at most 1.0 h. [0299] Preferably, in step (g) the viscous composition is allowed to cool to a third temperature below the first temperature and/or the second temperature. Preferably, step (g) involves allowing the viscous composition to cool to room temperature (23°C).
[0300] Preferably, in step (g) the third temperature is at least 16 °C; preferably at least 17 °C, more preferably at least 18 °C, still more preferably at least 19 °C, yet more preferably at least 20 °C, even more preferably at least 21 °C, most preferably at least 22 °C, and in particular at least 23 °C.
[0301] Preferably, in step (g) the third temperature is at most 34 °C; preferably at most 33 °C, more preferably at most 32 °C, still more preferably at most 31 °C, yet more preferably at most 30 °C, even more preferably at most 29 °C, most preferably at most 28 °C, and in particular at most 27 °C.
[0302] Preferably, in step (g) the third temperature is within the range of 25.0±9.0 °C; preferably 25.0±8.0 °C, more preferably 25.0±7.0 °C, still more preferably 25.0±6.0 °C, yet more preferably 25.0±5.0 °C, even more preferably 25.0±4.0 °C, most preferably 25.0±3.0 °C, and in particular 25.0±2.0 °C.
[0303] Preferably, step (g) is performed at an atmospheric relative humidity of at least 3% r.h.; preferably at least 7% r.h., more preferably at least 10% r.h., still more preferably at least 13% r.h., yet more preferably at least 17% r.h., even more preferably at least 20% r.h., most preferably at least 23% r.h., and in particular at least 27% r.h..
[0304] Preferably, step (g) is performed at an atmospheric relative humidity of at most 87% r.h.; preferably at most 83% r.h., more preferably at most 80% r.h., still more preferably at most 77% r.h., yet more preferably at most 73% r.h., even more preferably at most 70% r.h., most preferably at most 67% r.h., and in particular at most 63% r.h..
[0305] Preferably, step (g) is performed at an atmospheric relative humidity within the range of 45±40% r.h., preferably 45±35% r.h., more preferably 45±30% r.h., still more preferably 45±25% r.h., bet more preferably 45±20% r.h., and even more preferably 45±15% r.h..
[0306] In preferred embodiments, step (g) is performed at an atmospheric relative humidity of at least 21% r.h.; preferably at least 22% r.h., more preferably at least 23% r.h., still more preferably at least 24% r.h., yet more preferably at least 25% r.h., even more preferably at least 26% r.h., most preferably at least 27% r.h., and in particular at least 28% r.h..
[0307] In preferred embodiments, step (g) is performed at an atmospheric relative humidity of at most 39% r.h.; preferably at most 38% r.h., more preferably at most 37% r.h., still more preferably at most 36% r.h., yet more preferably at most 35% r.h., even more preferably at most 34% r.h., most preferably at most 33% r.h., and in particular at most 32% r.h..
[0308] In preferred embodiments, step (g) is performed at an atmospheric relative humidity within the range of 30±16% r.h.; preferably 30±14% r.h., more preferably 30±12% r.h., still more preferably 30±10% r.h., yet more preferably 30±8% r.h., even more preferably 30±6% r.h., most preferably 30±4% r.h., and in particular 30±2% r.h..
[0309] In preferred embodiments, step (g) is performed at an atmospheric relative humidity of at least 51% r.h.; preferably at least 52% r.h., more preferably at least 53% r.h., still more preferably at least 54% r.h., yet more preferably at least 55% r.h., even more preferably at least 56% r.h., most preferably at least 57% r.h., and in particular at least 58% r.h.. [0310] In preferred embodiments, step (g) is performed at an atmospheric relative humidity of at most 69% r.h.; preferably at most 68% r.h., more preferably at most 67% r.h., still more preferably at most 66% r.h., yet more preferably at most 65% r.h., even more preferably at most 64% r.h., most preferably at most 63% r.h., and in particular at most 62% r.h..
[0311] In preferred embodiments, step (g) is performed at an atmospheric relative humidity within the range of 60±16% r.h.; preferably 60±14% r.h., more preferably 60±12% r.h., still more preferably 60±10% r.h., yet more preferably 60±8% r.h., even more preferably 60±6% r.h., most preferably 60±4% r.h., and in particular 60±2% r.h..
[0312] In preferred embodiments, the solidified allulose composition obtained in step (g) has a purity of allulose of at least 92%, preferably at least 93%, more preferably at least 94%, still more preferably at least 95%, yet more preferably at least 96%, even more preferably at least 97%, relative to the dry solids content of the solidified allulose composition.
[0313] In preferred embodiments, the solidified allulose composition obtained in step (g) has a purity of allulose of at most 99%, preferably at most 98%, more preferably at most 97%, still more preferably at most 96%, yet more preferably at most 95%, relative to the dry solids content of the solidified allulose composition.
[0314] Solidification in step (g) typically provides a congealed mass that differs from the viscous composition obtained in preceding step (e) merely in that it has solidified and optionally, in that it has a lower content of volatile ingredients such as water. The solidified allulose composition obtained in step (g) typically contains all impurities besides allulose, e.g. fructose, HMF, color, and the like, that were likewise already contained in the aqueous allulose syrup provided in step (a), whereas it is contemplated that the content of certain impurities such as HMF and color may increase in the course of performing steps (b) through (g).
[0315] However, the solidified allulose composition obtained in step (g) typically consists of a single solid phase and differs from conventional crystallization processes where crystalline material is precipitated thereby providing the crystals as a solid phase and the mother liquor as a liquid phase. While the solidified allulose composition obtained in step (g) may contain residual amount of liquids, especially water, such liquids preferably do not form a separate liquid phase but are incorporated in the single solid phase.
[0316] In conventional crystallization processes where the crystalline phase is typically separated from the liquid phase (mother liquor), e.g. by filtration, a significant amount of impurities usually remains in solution of the mother liquor and only a comparatively low amount of impurities is entrained into the precipitated crystalline material, e.g. in form of inclusions, occlusions, and the like. Thus, in conventional crystallization processes, separating the solid phase from the liquid phase has a purifying effect. In contrast, according to the invention, the solidified allulose composition obtained in step (g) incorporates all impurities that were present in the viscous allulose composition and no purification is possible by phase separation due to the absence of a separate liquid phase.
[0317] It has been surprisingly found that the solidified allulose composition obtained in step (g) and optionally comminuted in step (h) (alternative (ii)) can be washed with suitable solvents, preferably alcohols, thereby removing a substantial amount of impurities such fructose, HMF and/or any coloring components.
[0318] Optional step (h) [0319] In optional step (h) of the process according to the invention, the solidified allulose composition is purified by (i) washing the solidified allulose composition with a solvent; or (ii) by comminuting the solidified allulose composition and subsequent washing the comminuted allulose composition with a solvent. In either case, the particulate allulose composition according to the invention is obtained.
[0320] According to alternative (i) of step (h), the solidified composition may already be present in particulate form, as solidification has provided a particulate material. Under these circumstances, a separate step of comminution is not necessary. According to alternative (ii) of step (h), the particulate character of the material is not sufficient such that the solidified composition is comminuted.
[0321] Washing may be performed by any suitable means that are known to the skilled person such as stirring, scurrying, rinsing, and the like. Preferably, after washing the solvent is separated from the solid by filtration, e.g. by means of a suction filter.
[0322] Preferably, the solvent is an alcohol or a mixture of an alcohol with water. Preferably, the alcohol is selected from ethanol and isopropanol; preferably ethanol.
[0323] Preferably, the weight ratio of solvent : solidified allulose composition is within the range of from 10:1 to 0.5:1; preferably 5:1 to 1:1.
[0324] Preferably, washing is performed for 0.1 to 20 minutes, more preferably 1 to 15 minutes, still more preferably 2 to 12 minutes.
[0325] As already mentioned above, alternatives (i) and (ii) of step (h) are preferably mutually exclusive. Thus, when the process comprises alternative (i) of step (h), it preferably does not include alternative (ii) of step (h), and vice versa.
[0326] According to alternative (ii) of step (h) of the process according to the invention, the solidified allulose composition is comminuted (e.g. fractured, broken, broken up, hackled, shred, disintegrated, chopped, sheared, crushed, disrupted, ruptured, beaten, bent, cut, milled, ground, pulverized, and the like) thereby obtaining the particulate allulose composition.
[0327] For the purpose of the specification, "comminution" may include any measure suitable to convert the solidified allulose composition, which typically is a congealed mass, into the particulate allulose composition. Typically, comminution involves subjecting the solidified allulose composition to mechanical impact. Suitable devices for achieving comminution are known to the skilled person. In preferred embodiments, comminuting involves a measure selected from the group consisting of fracturing, breaking, breaking up, hackling, shredding, disintegrating, chopping, shearing, crushing, disrupting, beating, bending, cutting, milling, grinding, and pulverizing.
[0328] Preferably, comminution is performed by means of a mill which may include but is not limited to a mill selected from the group consisting of autogenous mills, ball mills, disintegrators, pulverizers, screen mills, bead mills, disk mills, edge mills, hammer mills, malmal crushers, jet mills, air jet mills, roll mills, high pressure grinding roll mills, pin mills, planetary mills, vibrational mills, pebble mills, rod mills, SAG mills, and tower mills.
[0329] In a preferred embodiment, the particulates are rounded, i.e. to spheronized. This reduces the formation of undesired dust particles in the end product, in particular. [0330] Preferred devices used for the rounding are spheronizers, which essentially have a horizontally rotating disc onto which the particulates are pressed as a result of the centrifugal force onto the wall. As a result of the mechanical loading in the spheronizer, the particulates become rounded.
[0331] In preferred embodiments of the process according to the invention, after the washing in step (h), the thus obtained composition has an increased purity of allulose compared to the solidified allulose composition obtained in step (g); preferably wherein the purity of allulose is relatively increased by at least 0.5%, more preferably at least 1.0%, still more preferably at least 1.5%, yet more preferably at least 2.0%, even more preferably at least 2.5%, most preferably at least 3.0%, and in particular at least 3.5%.
[0332] In preferred embodiments of the process according to the invention, after the washing in step (h), the thus obtained composition has a decreased content of fructose compared to the solidified allulose composition obtained in step (g); preferably wherein the content of fructose is relatively decreased by at least 0.1 wt.%, more preferably at least 0.2 wt-%, still more preferably at least 0.3 wt-%, yet more preferably at least 0.4 wt-%, even more preferably at least 0.5 wt-%, most preferably at least 0.6 wt-%, and in particular at least 0.7 wt-%, relative to the total weight of the composition.
[0333] In preferred embodiments of the process according to the invention, after the washing in step (h), the thus obtained composition has an increased content of allulose compared to the solidified allulose composition obtained in step (g); preferably wherein the content of allulose is relatively increased by at least 0.5 wt.%, more preferably at least 1.0 wt-%, still more preferably at least 1.5 wt-%, yet more preferably at least 2.0 wt-%, even more preferably at least 2.5 wt-%, most preferably at least 3.0 wt-%, and in particular at least 3.5 wt-%, relative to the total weight of the composition.
[0334] In preferred embodiments of the process according to the invention, after the washing in step (h), the thus obtained composition has an increased dry solids content compared to the solidified allulose composition obtained in step (g); preferably wherein the dry solids content is relatively decreased by at least 0.1 wt.%, more preferably at least 0.2 wt-%, still more preferably at least 0.3 wt-%, yet more preferably at least 0.4 wt-%, even more preferably at least 0.5 wt-%, most preferably at least 0.6 wt-%, and in particular at least 0.7 wt-%, relative to the total weight of the composition.
[0335] In preferred embodiments of the process according to the invention, after the washing in step (h), the thus obtained composition has a decreased color compared to the solidified allulose composition obtained in step (g).
[0336] Optional subsequent steps
[0337] In preferred embodiments, the particulate allulose composition is subjected to a post-drying step. Preferably, the particulate allulose composition is post-dried in a manner such that the residual water content is not more than 5.0 wt-% and is preferably in the range of from 0.1 to 4.0 wt-%, in particular in the range from 0.5 to 3.0 wt-%, and specifically in the range of from 1.0 to 2.5 wt-%.
[0338] In preferred embodiments, the particulate allulose composition is subjected to a post-drying step, whereas post-drying is performed in a manner such that the residual content of solvent (other than water) is at most 1.0 wt- %; preferably at most 0.5 wt-%, more preferably at most 0.2 wt-%, and still more preferably at most 0.1 wt-%.
[0339] The post-drying step may be performed by means of conventional drying equipment such as a fluidized- bed drier in which a preferably heated gas, preferably air or a stream of nitrogen, is passed through the product layer from below. The amount of gas is preferably adjusted such that the particulates are fluidized and swirl. As a result of the gas/particle heat transition, the water is evaporated. Preferably, it is ensured that the temperature of the particulates does not increase too much, i.e. preferably not more than 80°C and more preferably not more than 70°C. The post-drying step may be performed by means of a conveyor belt. The post-drying can take place continuously or discontinuously.
[0340] After the optional post-drying, the particulates can also be fractionated (classified) by means of a sieve. Coarse material and fines can be ground and returned to the mixer for the purposes of mashing up the granulating mass.
[0341] Preferably, the particulate allulose composition has a degree of crystallinity of at least 1%; preferably at least 2%, preferably at least 3%, preferably at least 4%, preferably at least 5%, preferably at least 6%, preferably at least 7%, preferably at least 8%, preferably at least 9%, preferably at least 10%.
[0342] Preferably, the particulate allulose composition has a degree of crystallinity of at most 90%; preferably at most 80%, preferably at most 70%, preferably at most 60%, preferably at most 50%, preferably at most 40%, preferably at most 30%, preferably at most 20%, preferably at most 15%, preferably at most 10%, preferably at most 7.5%, preferably at most 5%, preferably at most 2.5%, preferably at most 1%.
[0343] Methods for determining the degree of crystallinity are known to the skilled person and include e.g. XRPD (x-ray powder diffraction) measurements in comparison to calibration curves that were determined for samples of known degree of crystallinity with an amorphous sample as one extreme and a single crystal as the other extreme.
[0344] Preferably, the particulate allulose composition is essentially amorphous.
[0345] Methods for determining the amorphous state of a solid material are known to the skilled person and include differential scanning calorimetry (DSC) and x-ray powder diffraction (XRPD).
[0346] Another aspect of the invention relates to a particulate allulose composition obtainable by the process according to the invention as described above.
[0347] Another aspect of the invention relates to a particulate allulose composition, preferably obtainable by the process according to the invention as described above, having a dissolution behavior such that when 100.0 g of the particulate allulose composition are dissolved in 100.0 mL of pure water having a temperature of 23.0 °C under stirring, the temperature of the thus obtained solution relatively decreases reaching a minimum of at least 18.3 °C, preferably at least 18.7 °C, still more preferably at least 19.0 °C, yet more preferably at least 20.0 °C, even more preferably at least 19.3 °C, most preferably at least 19.7 °C, and in particular at least 20.0 °C. Thus, heat is absorbed during dissolution, but the amount of heat being absorbed is relatively low such that the decrease of temperature of the solution is moderate only.
[0348] Preferably, the particulate allulose composition according to the invention has a solution enthalpy, preferably determined according to the method as described herein, of at most 13.0 cal/g, preferably at most 12.9 cal/g, more preferably at most 12.8 cal/g, still more preferably at most 12.7 cal/g, yet more preferably at most 12.6 cal/g, even more preferably at most 12.5 cal/g, most preferably at most 12.4 cal/g, and in particular at most 12.3 cal/g. [0349] Preferably, the solution enthalpy is at most 12.2 cal/g, preferably at most 12.1 cal/g, more preferably at most 12.0 cal/g, still more preferably al most 11.9 cal/g, yet more preferably at most 11.8 cal/g, even more preferably at most 11.7 cal/g, most preferably at most 11.6 cal/g, and in particular at most 11.5 cal/g.
[0350] Preferably, the solution enthalpy is at most 11.4 cal/g, preferably at most 11.3 cal/g, more preferably at most 11.2 cal/g, still more preferably al most 11.1 cal/g, yet more preferably at most 11.0 cal/g, even more preferably at most 10.9 cal/g, most preferably at most 10.8 cal/g, and in particular at most 10.7 cal/g.
[0351] Preferably, the solution enthalpy is at least 7.0 cal/g, preferably at least 7.5 cal/g, more preferably at least 8.0 cal/g, still more preferably at least 8.5 cal/g, yet more preferably at least 9.0 cal/g, even more preferably at least 9.5 cal/g, most preferably at least 10.0 cal/g, and in particular at least 10.5 cal/g.
[0352] In preferred embodiments of the particulate allulose composition according to the invention, the solution enthalpy is within the range of 9.0±1.6 cal/g, preferably 9.0±1.4 cal/g, more preferably 9.0±1.2 cal/g, still more preferably 9.0±1.0 cal/g, yet more preferably 9.0±0.8 cal/g, even more preferably 9.0±0.6 cal/g, most preferably 9.0±0.4 cal/g, and in particular 9.0±0.2 cal/g.
[0353] In other preferred embodiments of the particulate allulose composition according to the invention, the solution enthalpy is within the range of 10.0±1.6 cal/g, preferably 10.0±1.4 cal/g, more preferably 10.0±1.2 cal/g, still more preferably 10.0±1.0 cal/g, yet more preferably 10.0±0.8 cal/g, even more preferably 10.0±0.6 cal/g, most preferably 10.0±0.4 cal/g, and in particular 10.0±0.2 cal/g.
[0354] In further preferred embodiments of the particulate allulose composition according to the invention, the solution enthalpy is within the range of 11.0±1.6 cal/g, preferably 11.0±1.4 cal/g, more preferably 11.0±1.2 cal/g, still more preferably 11.0±1.0 cal/g, yet more preferably 11.0±0.8 cal/g, even more preferably 11.0±0.6 cal/g, most preferably 11.0±0.4 cal/g, and in particular 11.0±0.2 cal/g.
[0355] In still further preferred embodiments of the particulate allulose composition according to the invention, the solution enthalpy is within the range of 12.0±1.6 cal/g, preferably 12.0±1.4 cal/g, more preferably 12.0±1.2 cal/g, still more preferably 12.0±1.0 cal/g, yet more preferably 12.0±0.8 cal/g, even more preferably 12.0±0.6 cal/g, most preferably 12.0±0.4 cal/g, and in particular 12.0±0.2 cal/g.
[0356] Preferably, the particulate allulose composition according to the invention has a particle shape determined by dynamic image analysis in accordance with ISO 13322-2, wherein the quotient [b/l(46o> ■ b/l(5>] of
- the ratio b/l(46o> of particle breadth b to particle length 1 measured at a dispersion pressure of 460 Pa and
- the ratio b/l(5> of particle breadth b to particle length 1 measured at a dispersion pressure of 5 Pa is at most 1.40, preferably at most 1.35, more preferably at most 1.30, still more preferably at most 1.25, yet more preferably al most 1.20, even more preferably at most 1.15, most preferably at most 1.10, and in particular at most 1.05.
[0357] Preferably, the particulate allulose composition obtained in step (h) of the process according to the invention is a powder. The powder is preferably characterized by its average particle size and particle size distribution.
[0358] Suitable methods for determining the average particle size and the particle size distribution of a powder are known to a skilled person. Suitable methods include but are not limited to sieve analysis (gradation), laser diffraction, and dynamic picture analysis. [0359] Preferably, the particulate allulose composition obtained in step (h) has a residual water content of at least 0.05 wt-%; preferably at least 0.10 wt-%, preferably at least 0.15 wt-%, preferably at least 0.20 wt-%, preferably at least 0.25 wt-%, preferably at least 0.30 wt-%, preferably at least 0.35 wt-%, preferably at least 0.40 wt-%, preferably at least 0.45 wt-%, preferably at least 0.50 wt-%; relative to the total weight of the particulate allulose composition.
[0360] Preferably, the particulate allulose composition obtained in step (h) has a residual water content of at most
4.5 wt-%; preferably at most 4.4 wt-%, preferably at most 4.3 wt-%, preferably at most 4.2 wt-%, preferably at most 4.1 wt-%, preferably at most 4.0 wt-%, preferably at most 3.9 wt-%, preferably at most 3.8 wt-%, preferably at most 3.7 wt-%, preferably at most 3.6 wt-%, preferably at most 3.5 wt-%, preferably at most 3.4 wt-%, preferably at most 3.3 wt-%, preferably at most 3.2 wt-%, preferably at most 3.1 wt-%, preferably at most 3.0 wt-%, preferably at most 2.9 wt-%, preferably at most 2.8 wt-%, preferably at most 2.7 wt-%, preferably at most
2.6 wt-%, preferably at most 2.5 wt-% ; relative to the total weight of the particulate allulose composition.
[0361] Preferably, the particulate allulose composition obtained in step (h) has a residual water content of at most
2.5 wt-%; preferably at most 2.4 wt-%, preferably at most 2.3 wt-%, preferably at most 2.2 wt-%, preferably at most 2.1 wt-%, preferably at most 2.0 wt-%, preferably at most 1.9 wt-%, preferably at most 1.8 wt-%, preferably at most 1.7 wt-%, preferably at most 1.6 wt-%, preferably at most 1.5 wt-%, preferably at most 1.4 wt-%, preferably at most 1.3 wt-%, preferably at most 1.2 wt-%, preferably at most 1.1 wt-%, preferably at most 1.0 wt-%, preferably at most 0.9 wt-%, preferably at most 0.8 wt-%, preferably at most 0.7 wt-%, preferably at most 0.6 wt-%, preferably at most 0.5 wt-% ; relative to the total weight of the particulate allulose composition.
[0362] Preferably, the particulate allulose composition obtained in step (h) has an allulose content of at least 90 wt-%, preferably at least 91 wt-%, preferably at least 92 wt-%, preferably at least 93 wt-%, preferably at least 94 wt-%, preferably at least 95 wt-%, preferably at least 96 wt-%, preferably at least 97 wt-%, preferably at least 98 wt-%, preferably at least 99 wt-%; relative to the total weight of the particulate allulose composition.
[0363] Preferably, the particulate allulose composition obtained in step (h) has an allulose content of at most
99.5 wt-%; preferably almost 99.0 wt-%, preferably at most 98.5 wt-%, preferably almost 98.0 wt-%, preferably at most 97.5 wt-%, preferably at most 97.0 wt-%, preferably at most 96.5 wt-%, preferably at most 96.0 wt-%, preferably at most 95.5 wt-%, preferably at most 95.0 wt-%; relative to the total weight of the particulate allulose composition.
[0364] Preferably, the particulate allulose composition obtained in step (h) has a fructose content of at least 0.05 wt-%; preferably at least 0.10 wt-%, preferably at least 0.15 wt-%, preferably at least 0.20 wt-%, preferably at least 0.25 wt-%, preferably at least 0.30 wt-%, preferably at least 0.35 wt-%, preferably at least 0.40 wt-%, preferably at least 0.45 wt-%, preferably at least 0.50 wt-%; relative to the total weight of the particulate allulose composition.
[0365] Preferably, the particulate allulose composition obtained in step (h) has a fructose content of at most 10 wt-%; preferably at most 9.0 wt-%, preferably at most 8.0 wt-%, preferably at most 7.0 wt-%, preferably at most 6.0 wt-%, preferably at most 5.0 wt-%, preferably at most 4.0 wt-%, preferably at most 3.0 wt-%, preferably at most 2.0 wt-%, preferably at most 1.0 wt-%; relative to the total weight of the particulate allulose composition. [0366] Preferably, the average particle size and all other parameters that are useful to describe the particle size, shape and distribution of the particulate allulose composition obtained in step (h) are determined by optical methods, preferably by dynamic picture analysis according to ISO 13322-2. In this regard, the average particle size preferably corresponds to the value Mv (also referred to as "mean diameter" and "Mv3(x)", respectively). ISO 13322-2:2006 describes methods for controlling the position of moving particles in a liquid or gas and on a conveyor, as well as the image capture and image analysis of the particles. These methods are used to measure the particle sizes and their distributions, the particles being appropriately dispersed in the liquid or gas medium or on the conveyor. A suitable device is the particle size analyzer Camsizer® XT (Retsch Technology GmbH, Haan, Germany; X-Jet Module, 30 kPa for dispersion).
[0367] The following examples further illustrate the invention but are not to be construed as limiting its scope.
[0368] Example 1 - variation of dry solids content:
[0369] Three different concentrated compositions were prepared originating from the same aqueous allulose syrup. The purity of allulose was identical (> 95 wt-% relative to dry solids content), but the dry substance content was different: 97.0 wt-% for sample 1, 96.0 wt-% for sample 2, and 95.0 wt-% for sample 3. To each sample, 10 wt-% seed crystals of allulose were added having identical average particle size. All samples were stirred at 30°C overnight at 50 rpm under controlled conditions with a stirrer having a maximum torque of 200 Ncm. The thus treated samples were heated to 70°C for removal from stirring equipment and pored onto trays this forming thin films of material. The viscous compositions were allowed to solidify under ambient conditions.
[0370] The experimental results are summarized in the table here below:
[0371] These experimental results suggest that solidification depends upon the dry solids content. Depending upon the individual experimental conditions, solidification can be achieved within short periods of time when the dry solids content is within a certain range having lower and upper limit. Under the given experimental conditions, the optimum dry substance content was about 96 wt-%, relative to the total weight of the concentrated composition (sample 2).
[0372] Example 2 - variation of conditions for congealing and solidification:
[0373] In accordance with Example 1, samples 1 to 3 were stored for 24 h under controlled conditions (temperature and relative humidity). Before and after storage, the hardness of the compositions was measured by means of a texture analyzer (TA.XTplusC, force measuring cell 50 N) that measures the force which is necessary in order to penetrate a pin into the material for a predetermined distance. The residual water content was determined according to Karl Fischer titration.
[0374] The tested storage conditions are summarized in the table here below: [0375] The results shown in Figure 1 (texture analyzer) and Figure 2 (Karl Fischer) relate to storage conditions 25 °C/60% r.h., 40 °C/10% r.h., and 25 °C/30% r.h.
[0376] Best results were obtained after storage at 25 °C and 30% r.h. While higher storage temperatures had a beneficial effect on reduction of residual water content, they resulted in deteriorated solidification efficiencies.
[0377] The results for samples 1 to 3 after storage at 25 °C/30% r.h. are summarized in the table here below:
[0378] It was further investigated that when forming the viscous material into films, the film thickness has an effect on solidification. The thinner the film, the faster solidification.
[0379] Example 3 - variation of initial stirring temperature:
[0380] In accordance with Examples 1 and 2, the concentrated composition of sample 2 (dry substance content 96.0 wt.-%) was stirred at different initial temperatures in order to investigate the influence of initial stirring temperature on subsequent solidification and product characteristics: 30 °C for sample 2-1, 40 °C for sample 2-2, and 50 °C for sample 2-3. The observations are summarized in the table here below:
[0381] The thus obtained viscous compositions were poured onto trays and dried under controlled conditions at 25 °C/10% r.h. and 25 °C/30% r.h.. Hardness of the compositions was measured at different time points by means of the texture analyzer and the results are shown in Figure 3 (25 °C/10% r.h.) and Figure 4 (25 °C/30% r.h.).
[0382] Example 4 - variation of film thickness:
[0383] In accordance with Example 3, the concentrated compositions of samples 2-1, 2-2 and 2-3 (dry substance content 96.0 wt-%, initial stirring temperatures 30 °C, 40 °C and 50 °C, respectively) were each formed into films of various thickness: 2 mm, 3.5 mm, and 5 mm. After storage for 24 hours at 25 °C/30% r.h., the obtained compositions were comminuted and characterized. While sample 2-1 at any thickness did not completely solidify, samples 2-2 and 2-3 provided solidified and brittle material.
[0384] Tackiness was determined and quantified according to a scale from 1 (hardly tacky) to (6 very tacky). The observations are summarized in the table here below:
[0385] Thus, films having a thickness of 2 mm provide the best results, whereas stirring at an initial temperature of 40 °C is better than stirring at an initial temperature of 30 °C or 50 °C. These experimental results suggest that solidification depends upon the initial stirring temperature and film thickness. Depending upon the individual experimental conditions, solidification can be achieved within short periods of time when the initial stirring temperature is within a certain range having lower and upper limit. Under the given experimental conditions, the optimum stirring temperature was about 40 °C (sample 2-2). Further, film thickness also has a beneficial influence on solidification and reduction of tackiness. In either case, best results are achieved with thin films.
[0386] Example 5 - variation of amount of seed crystals:
[0387] In accordance with Example 2-2 (dry substance content 96.0 wt-%, initial stirring temperature 40 °C), the amount of seed crystals of allulose was varied: 1 wt-% for A, 2 wt-% for B, and 5 wt-% for C, relative to the total weight of the seeded suspensions). The observations are summarized in the table here below:
[0388] The results of the texture analysis are shown in Figure 5. While solidified allulose compositions having the hardest surface could be obtained with the lowest amount of seed crystals of allulose (1 wt-%, sample 2-2 A), hardness did not significantly change after about 3 hours of storage.
[0389] Figure 6 compares results of the texture analysis of materials obtained by the process according to the present invention with a comparative material obtained by a comparative process involving extmsion technology.
[0390] Example 6 - further increasing the amount of seed crystals:
[0391] In accordance with Example 2-2, seed crystals of allulose were added in amounts of 3 wt-%, 6 wt-% and 10 wt-%. Stirring was started at an initial stirring temperature of 40 °C and was terminated when the viscous composition had reached a predetermined viscosity (torque) so that it could be concluded that sufficient mechanical energy had been introduced. The thus obtained viscous compositions were poured onto trays and formed into films that were stored at 25 °C/30% r.h. The hardness of the solidified allulose compositions was measured at various time points by means of the texture analyzer. The experimental results are shown in Figure 7.
[0392] As shown, when adding an amount of 10 wt-% of seed crystals of allulose, the thus obtained seeded suspension only needed about 1 hour until the predetermined viscosity (torque) was reached such that stirring could be terminated. Further, the thus obtained viscous composition only needed about 1 additional hour until the thus obtained solidified allulose composition had reached a hardness of more than 500 units. The other two samples required extended stirring times and did not achieve comparable mechanical properties, also not after extended storage times.
[0393] Example 7 - using various starting materials and subsequent washing of solids with alcoholic solvents:
[0394] Two particulate allulose compositions were prepared.
[0395] In Example 7-1, allulose syrup was used as starting material (step (a)) that had not been subjected to any decoloring, chromatography, treatment with adsorbing agents, or any other purification measures. Water was evaporated (step (b)) and then the thus obtained crude allulose syrup was further processed by introducing mechanical energy and by solidification in accordance with Example 2. The thus obtained particulate allulose composition had the following properties:
[0396] In Example 7-2, centrifuge drain was used as starting material (step (a)) that had been used as mother liquor for the preparation of crystalline allulose and that had not been subjected to any decoloring, chromatography, treatment with adsorbing agents, or any other purification measures. Water was evaporated (step (b)) and then the thus obtained crude allulose syrup was further processed by introducing mechanical energy and by solidification in accordance with Example 2. The thus obtained particulate allulose composition had the following properties:
[0397] In either case, the particulate allulose composition was coarsely ground and sieved through a 1.0 mm mesh to give a resultant particle size of <1.0 mm.
[0398] In either case, 20 g of the solids obtained in this way were mixed with 40 g of solvent, namely an alcohol or an aqueous alcohol (5% water content). After stirring for a period of about 10 min, the solvent was filtered off using a suction filter. The resulting solid was not further conditioned and promptly analyzed.
[0399] Results are compiled in the table here below:
[0400] It can be seen that mainly due to washing with ethanol,
- the color decreases significantly (Example 7-lb: 101 IU — >• 16 IU; Example 7-2b: 1118 IU — >• 163 IU);
- the purity increases sharply (Example 7-lb: 97.3% — > 99.7%; Example 7-2b: 94.4% — > 99.4%); and
- the dry substance content increases significantly (Example 7-lb: 99.4% — > 100.0%; Example 7-2b: 99.0% — > 100.0%).
[0401] The increase in dry substance content due to the addition of ethanol also indicates another positive effect. Addition of ethanol after discharge from the container, in which the mechanical energy is introduced thereby leading to the formation of solids, significantly reduces the time that is required for step (g) of the process according to the invention and/or simplifies the overall process.
Example 8 - solution enthalpy:
[0402] The solution enthalpies of two particulate allulose compositions that were prepared in accordance with the invention (mechanical energy introduced by stirrer and by pressure beater, respectively) were measured and compared to the solution enthalpies of two conventional crystalline allulose samples (fine grade and coarse grade, respectively). [0403] The measurement of solution enthalpy was performed with a 6755 Solution Calorimeter (Parr Instruments). The calorimeter was calibrated with 0.50 g TRIS (Tris-(hydroxymethyl)-aminomethane. Energy input QE was calculated and the energy equivalent e (cal/°C) of the calorimeter was derived therefrom (e = QE / Tc).
[0404] Samples were prepared by mortaring and weighing from 0.120 to 0.510 g. The thermogram was measured to determine the temperature rise Tc. The energy change was calculated (Q = Tc / e). The (specific) solution enthalpy was calculated (H T = -Q / m).
[0405] Measures solution enthalpies are compiled in the table here below:
[0406] It can be seen that the particulate allulose composition according to the invention significantly differs from conventional particulate allulose that has been prepared by conventional crystallization.
Example 9 - properties of particles:
[0407] The properties of the particles of the particulate allulose composition according to the invention were compared to the properties of conventional particles of crystalline allulose of comparable size.
[0408] Particle size measurements were performed by means of a Camsizer X2 (Retsch Technology). Particle size analysis is based upon dynamic image analysis (ISO 13322-2). Information can be provided regarding particle size and shape of powders, granules and suspensions in a measuring range of from 0.8 pm to 8 mm.
[0409] The particles were dispersed and separated by compressed air (X-Jet). Measurements were carried out at three different dispersion pressures: 5 kPa, 20 kPa, and 460 kPa. The value XCmin was determined which represents the width of particles that in conventional sieve analysis would pass a sieve of the size.
[0410] Samples were prepared by grinding in a stand mixer and subsequent fractionation by a sieve of suitable mesh size.
[0411] Figure 8 shows the needle-like shape of conventional crystalline allulose particles, fractionation 100-200 pm.
[0412] Figures 9 and 10 show the more spherical shape of allulose particles according to the invention, Figure 9 at fractionation 100-200 pm, Figure 10 at fractionation 100-125 pm.
[0413] Particle size distributions dlO, d50 and d90 were determined for each sample at the different dispersion pressures. The results are compiled in the table here below: [0414] Particle shape analysis provided additional information regarding particle breadth b versus particle length 1. The aspect ratio is a measure for the needle-like shape.
[0415] For the fraction of 200-500 pm, the ratios b/1 were determined for each sample. A comparison of b/1 at a dispersion pressure of 460 kPa with b/1 at a dispersion pressure of 5 kPa. The ratios b/1 at 460 kPa to b/1 at 5 kPa are compiled in the table here below:
[0416] The particle size analysis was repeated without fractionation. A comparison of b/1 at a dispersion pressure of 460 kPa with b/1 at a dispersion pressure of 5 kPa. The ratios b/1 at 460 kPa to b/1 at 5 kPa are compiled in the table here below:
[0417] It can be seen that the particle shape of conventional crystalline allulose particles is more sensitive towards different dispersion pressures than the particle shape of the allulose particles according to the invention.
[0418] Example 10 - variation of pH:
[0419] In accordance with previous Examples, the allulose syrup was concentrated to a dry substance content of 96.0 wt.-%. Before being concentrated, different pH values of the initial allulose syrup were investigated.
[0420] To each sample, 10 wt-% seed crystals of allulose were added having identical average particle size. All samples were stirred at 40°C at 100 rpm under controlled conditions with a stirrer having a maximum torque of 400 Ncm. The time at which the maximum torque was reached was noted as the solidification time.
[0421] These experimental results suggest that solidification depends upon the pH value of the allulose syrup. A short solidification can be achieved by a higher pH value of the allulose syrup.