PLANT MATERIAL

FIELD OF INVENTION

[0001] The present invention relates to a process for recovering at least one compound of plant material, by means of high vacuum water steam stripping.

BACKGROUND OF INVENTION

[0002] The extraction of natural products from plant material can be carried out by several methods that typically use one or more organic solvents depending on the nature of the compound to be extracted from the plant material. Thus, plant compounds such as plant secondary metabolites that are of particular interest for the fragrance, the cosmetical, the pharmaceutical, and the food industry are conventionally obtained by extraction in a continuous phase of at least one organic solvent. However, the use of organic solvents in the industry is neither cost-effective nor environment- friendly. Furthermore, organic solvents extract a broad spectrum of compounds in the continuous phase and consequent separative techniques need to be applied so as to isolate a compound or a class of compounds that needs to be recovered. Lastly, the organic solvent residues may be detrimental for the human health during plant processing or during the use of the products enabling the extracted compounds.

[0003] Essential oils, formed substantially by odorous compounds are, for their part, generally obtained by distillation with an aqueous mobile phase (hydro-distillation). Such technique is free of organic solvent. However, hydro-distillation subjects sensitive compounds to high temperatures leading to their thermal degradation, such as for example oxidation.

[0004] Furthermore, the known separative techniques are limited by the fact that the compounds to be need to be dissolved in the continuous or the mobile phase constituted by the organic solvent or the hydro-distillation water. Under the known extraction techniques’ principles, there is an equilibrium between the compounds in the mobile or the continuous phase and the compounds that remain in the plant material. Hence, during the processes of the art there is a costly need for continuously renewing the mobile phase in order to shift the equilibrium towards the dissolution of the plant compounds in the mobile phase.

[0005] Therefore, there is a need to supply a process for recovering compounds from plant material, in a cost-effective and environmentally-friendly manner that preserves the stability of the compounds to be recovered. Furthermore, there is a need for a process for recovering compounds that is selective for at least one compound or a class of compounds.

[0006] The Applicant found out that water steam-striping plant material under high vacuum conditions as defined in the present invention, gives a solution to the above shortcomings. Indeed, under high-vacuum conditions, the water steam carries away the at least one compound to be recovered by removing it from the plant material without subjecting the plant material or the at least one compound to high temperatures and the concomitant oxidative conditions. Furthermore, the process does not enable organic solvents and is not limited by the equilibrium of a compound passing from the solid phase of the plant material to the liquid phase used in the extraction methods of the art.

[0007] According to a further advantageous aspect of the present process, the high- vacuum water steam allows the selective recovery of specific compounds or specific class of compounds such as for example the essential oil compounds. In other terms, the process allows the selective isolation of at least one, at least two compounds or of a class of compounds among the plethora of metabolites that are present in a plant material. Thus, according to an advantageous aspect, the process can least to a selective isolation thereby avoiding subsequent purification or fractionation steps. In a still further advantageous aspect of the process, the water steam carrying the at least one compound to be recovered can be recycled in the process steps, thereby further high-lighting the economic and environment friendly advantages of the process according to the invention. SUMMARY

[0008] The present invention relates to a process for recovering at least one compound from a plant material comprising water steam stripping said plant material under high vacuum, wherein said high vacuum presents an absolute atmospheric pressure of less or equal to 200 mbar, preferably less or equal to 100 mbar, more preferably less or equal to 50 mbar, still more preferably less or equal to 35 mbar; and wherein said water steam presents a temperature ranging from 30°C to 60°C, so as to remove the at least one compound from the plant material, and recovering the at least one compound from the water steam.

[0009] The process may comprise the steps of: i. subjecting the raw plant material to high vacuum, said high vacuum presenting an absolute atmospheric pressure of less or equal to 200 mbar, preferably less or equal to 100 mbar, more preferably less or equal to 50 mbar, still more preferably less or equal to 35 mbar; ii. steam- stripping under the high vacuum by injecting water or water steam under the high-vacuum in the plant material, said water steam presenting a temperature ranging from 30°C to 60°C, so as to remove the at least one compound from the plant material, said water steam carrying the at least one compound away from the raw plant material, iii. condensing the injected water steam carrying the at least one compound leading to an aqueous composition comprising the at least one compound, iv. separating the at least one compound from the aqueous composition of step (iii) and recovering the at least one compound and a water phase.

[0010] In one embodiment, the condensing step is carried-out with at least one chiller heat exchanger, preferably said at least one chiller heat exchanger presenting a temperature ranging from -10°C to 10°C.

[0011] The water steam under high- vacuum removes the at least one compound by adsorption, typically by creating hydrogen bonds with the at least one compound. [0012] In case the at least one compound is water immiscible wherein the step of separating the at least one compound from the aqueous water phase is carried out by mechanical phase separation of the water phase.

[0013] When the at least one compound is water miscible, the step of separating the at least one compound from the aqueous water phase is carried out by crystallization

[0014] The process according to the invention may further comprise agitating the plant material during step (i) and/or step (ii).

In some embodiments, the process further comprises recycling the water phase of step (iv) by injecting it as water in the steam- stripping step (ii).

[0015] Typically, the at least one compound to be recovered presents a molecular weight of less or equal than 300 g/mol, preferably less or equal than 250 g/mol, even more preferably less or equal than 200 g/mol, still more preferably less than 160 g/mol.

[0016] The at least one compound is at least one compound selected from the group consisting of alcohols, phenols, esters, short-chain carboxylic acids (i.e. presenting a Cl- C8, preferably C1-C4 carbon chain), unsaturated terpenes and terpene oxides.

[0017] The plant material is selected from whole plants, plant aerial parts, leaves, stems, flowers, wood, bark, roots, rhizomes, fruits and fruit pericarps.

[0018] Furthermore, the at least one compound is typically at least one compound of an essential oil.

[0019] According to some exemplary embodiments, the plant material is Mentha spp aerial parts and wherein the at least one compound is menthol or carveol, preferably carveol; or wherein the plant material is Citrus and the at least one compound is limonene.

[0020] According to some other exemplary embodiments, the plant material is selected from cloves, anise and vanilla pods and wherein the at least one compound is selected from eugenol, anisole and vanillin respectively. [0021] Lastly, the invention further relates to a system for carrying out the process of the invention, said system comprising:

- a reactor, preferably a columnar recipient, typically an agitating device, presenting a first and a second plane and an optionally heated circumferential surface,

- a chamber surrounding the columnar blending device recipient with means for air-sealing,

- at least one pump for applying high vacuum and a vacuum inlet configured to apply a high vacuum less or equal to 200 mbar, preferably less or equal to 100 mbar, more preferably less or equal to 50 mbar, still more preferably less or equal to 35 mbar in the chamber,

- means for injecting water or water steam at a temperature ranging from 30°C to 60°C in the first plane of the columnar recipient,

- means for condensing the injected water steam with the at least one compound from the second plane of the columnar recipient.

DEFINITIONS

[0022] In the present invention, the following terms have the following meanings:

[0023] “About”, preceding a figure means plus or less 10% of the value of said figure, preferably plus or less 5% of the value of said figure, in particular plus or less 1% of the value of said figure.

[0024] “Steam-volatile” in the context of the present invention refers to compounds, such as off-flavor compounds, that can be removed from the raw plant material upon contact with high-vacuum steam. The steam-volatile compound removal under high- vacuum may include (1) lowering the boiling point of the steam- volatile compound thereby volatilizing it and removing it from the raw plant material under high-vacuum conditions and/or (2) the diffusion of the steam- volatile compound to the outer surfaces of the raw plant material and the removal of steam- volatile compound by the high-vacuum steam, typically thanks to the hydrogen bonds formed between the steam and the off- flavor compounds. Preferably, the steam-volatile compound removal under high-vacuum includes the diffusion (2) of the steam-volatile compounds as detailed above. It is therefore understood that even if compounds are not volatile stricto sensu under high vacuum conditions, they are rendered steam-volatile by the water steam under high vacuum steam conditions.

DETAILED DESCRIPTION

[0025] The invention relates to a process for recovering at least one compound from a plant material comprising steam stripping said plant material under high vacuum.

[0026] Steam stripping is understood as injecting water steam through the plant material. It is further understood that under high vacuum conditions the water steam can present a lower temperature than the boiling point of water at sea lever of about 1013 mbar.

[0027] Thus, the invention relates to a process for recovering at least one compound from a plant material comprising steam stripping said plant material under high vacuum, wherein said high vacuum presents an absolute atmospheric pressure of less or equal to 200 mbar, preferably less or equal to 100 mbar, more preferably less or equal to 50 mbar, still more preferably less or equal to 35 mbar; and wherein said water steam presents a temperature ranging from 30°C to 60°C, so as to remove the at least one compound from the plant material, and recovering the at least one compound from the water steam. Advantageously, no thermal treatment, such as blanching, of the plant material is applied to the plant material before the steam-stripping according to the invention.

[0028] Typically, the plant material is inserted in a reactor, such as a cylindrical recipient, that is subjected to the high-vacuum, wherein the plant material defines a lower and an upper surface. The water steam is injected to the lower surface or the upper surface of the plant material, preferably to the lower surface. The process may optionally comprise agitating the plant material, typically in the cylindrical recipient.

[0029] According to a first variant the water steam is injected in the form of water steam, typically at the high-vacuum and temperature conditions of the process as defined above. [0030] According to a second and preferred variant, the water steam is injected in the form of liquid water having a temperature of about 30°C to about 70°C, preferably about 60°C, that is instantly converted in water steam once subjected to the high-vacuum conditions of the process. Thus, under the high vacuum conditions of the process, water is injected in a manner that keeps the plant material hydrated without submerging it into a liquid phase. The suitable amount and flow rate of the water steam may vary, and depend on several parameters such as the nature of the plant material, the amount of said plant material and/or the volume of the cylindrical recipient. Monitoring the hydration can be carried out by any means known in the art, such as for example visual inspection of plant material samples during the process. For instance, the water steam flow rate may be comprised between 10 and 1000 kg/hour, preferably between 50 and 200 kg/hour. In some embodiments, the water steam flow rate may be of about 100kg per hour, for instance for a 4 tons per batch.

[0031] The temperature of the water steam may vary in a wide range. In some embodiments, the water steam presents a temperature ranging from about 30°C to about 60°C. Preferably, the water steam presents a temperature of less than about 50°C, even more preferably less than about 35°C, typically the water steam presents a temperature ranging from about 30°C to about 45°C. It is understood that when the invention is implemented according to a second variant wherein the water steam is injected in the form of liquid water having a temperature of about 30°C to about 70°C, preferably about 50°C, that is instantly converted in water steam once injected to the high-vacuum conditions of the process and cooled to the water-steam temperatures detailed above, typically by reaching the saturation temperature in the vacuum conditions inside the columnar device.

[0032] Typically, the water steam after being injected in the plant material removes or carries away the at least one compound from the plant material and the generated watersteam comprising the at least one compound may be condensed on a surface, preferably on a surface of a chiller heat exchanger even more preferably a chiller heat exchanger at a temperature comprised between about -10°C and 10°C, preferably from -5°C to 10°C, more preferably from -2°C to 8°C to condense the water-steam comprising the at least one compound.

[0033] Advantageously, the process according to the invention allows the recovery of said at least one compound that is rendered steam-volatile as defined above under the high-vacuum conditions of the process without subjecting the plant or said at least one compound at high temperatures, thereby maintaining the stability of said at least one compound, i.e. by impeding any oxidation or hydrolysis thereof. According to an advantageous aspect of the invention, the process does not encompass energy consuming supercritical or sublimated gasses, such as supercritical or sublimated carbon dioxide. Furthermore, compared to the extraction processes of the art, such as hydro-distillation, the process according to the invention is far lower-demanding in terms of energy consumption and in terms of effluents and waste disposal costs.

[0034] According to one embodiment, the process, comprises the steps of: steam- stripping the plant material under high vacuum of less or equal to about 200 mbar, preferably less or equal to 100 mbar, more preferably less or equal to 50 mbar, still more preferably less or equal to 35 mbar, such as less or equal to 15 mbar, less or equal to about 5 mbar, or lower than 0.1 mbar; said steam- stripping comprising injecting water or water steam to the plant material; said water steam presenting a temperature ranging from about 30°C to about 60°C, preferably a temperature of less than about 50°C, even more preferably less than about 45 °C, typically the water steam presenting a temperature ranging from about 30°C to about 45 °C; condensing the water steam after being injected in the plant material, preferably with a chiller heat exchanger even more preferably a chiller heat exchanger at a temperature comprised between about -10°C and 10°C to condense the water-steam comprising the at least one compound.

[0035] According to one embodiment, the process comprises the steps of: i. subjecting the raw plant material to high vacuum, said high vacuum presenting an absolute atmospheric pressure of less or equal to 200 mbar, preferably less or equal to 100 mbar, more preferably less or equal to 50 mbar, still more preferably less or equal to 35 mbar; ii. steam- stripping under the high vacuum by injecting water or water steam under the high-vacuum in the plant material, said water steam presenting a temperature ranging from 30°C to 60°C, so as to remove the at least one compound from the plant material, said water steam carrying the at least one compound away from the raw plant material, iii. condensing the injected water steam carrying the at least one compound leading to an aqueous composition comprising the at least one compound, iv. separating the at least one compound from the aqueous composition of step (iii) and recovering the at least one compound and a water phase.

[0036] Steps (i) to (iv) are preferably implemented in the recited order. Additional further and/or intermediate treatment and/or recovery steps may be comprised before and/or after any recited steps of the process according to the invention. Applying the high vacuum (i) and injecting the water steam (ii) according to the invention may be carried out sequentially or simultaneous, continuously or intermittently.

[0037] Step (i) may be implemented by any suitable technique. Optional agitation at step (i) may be performed for instance by mechanical and/or magnetic stirring, for instance with screws. For instance, step (i) may be implemented in a columnar blending device presenting a first plane, a second plane and an, optionally heated, circumferential surface at a temperature ranging from about 35°C to about 50°C. When heating is applied during step (i), it is applied once the high vacuum conditions are established. According to an advantageous aspect of the invention, no temperature raise is applied to the plant material or to the columnar device. It is understood that the subjecting plant material to heating can be carried out with little or no temperature shifts, given the instant water evaporation that takes place under the high vacuum conditions. Thus, in one preferred embodiment, the temperature is kept constant throughout the process. [0038] When step (i) is implemented in a columnar device as described above, step (ii) may be implemented by injecting (ii) the water steam or water to the first plane of the columnar device. Preferably, step (ii) is carried out in a manner that keeps the plant material hydrated without submerging it into a liquid phase. According to one embodiment, step (ii) further comprises heating the recipient, typically the circumferential surface (walls) of the recipient such as the columnar device described above, more preferably in a manner that the heating compensates the water evaporation so as to keep the temperature stable.

[0039] Step (iii) may be implemented by any suitable technique. Typically, step (iii) may be carried-out by condensation, typically with a chiller heat exchanger. The temperature of step (iii) may vary in a wide range. In some embodiments, the condensation temperature at step (iii) is comprised between about -10°C and 10°C, preferably from -5°C to 10°C, more preferably from -2°C to 8°C. When step (ii) is implemented in a columnar device as described above, the injected water steam containing the at least one compound may be recovered at step (iii) from the second plane of the device. Once step (iii) is completed, the condensed water and the at least one compounds are condensed in the form of an aqueous composition that may be a solution, a solid dispersion of the at one compound in the water phase of the aqueous composition, or an oil dispersion of the at one compound in the water phase of the aqueous composition. Then, the pressure may be restored to atmospheric pressure with atmospheric air or nitrogen.

[0040] Each step or group of steps of the process according to the invention may be repeated several times if necessary and/or to obtain a desired level of recovery of the at least one compound.

[0041] In some embodiments, the process according to the invention reiterates steps (ii) and (iii) in order to ensure a quantitative recovery of the at least one compound. Steps (ii’) and (iii’) are identical to steps (ii) and (iii) respectively. Steps (ii’) and (iii’) may also be referred to as a new cycle of steps (ii) and (iii).

[0042] The separation step (iv) may be carried out by any separative means in the art, leading to the recovery of the at least one compound and a water phase. The separation step of the at least one compound from the condensed aqueous composition of step (iii) is typically carried out by crystallization or by mechanical phase separation.

[0043] When the at least one compound is water immiscible, thereby forming a biphasic system of a water phase and a phase of the at least one compound, for example an oil phase or a solid dispersion, the step of separating the at least one compound from the aqueous water phase can be carried out by mechanical phase separation of the water phase, such as for example by a separatory funnel or filtering.

[0044] When the at least one compound is water miscible, thereby forming a monophasic aqueous composition of a water phase dissolving the at least one compound, the step of separating the at least one compound from the aqueous water phase can be carried out by crystallization. It is understood that crystallization may already take place under the condensation conditions of step (iii). In that case, step (iv) may comprise applying means for completing the initiated crystallization such as co -crystallization or cooling the condensate of step (iii) in order to complete the recovery of the at least one compound from the aqueous composition, thereby leading to the recovery of the at least one compound and of a water phase.

[0045] According to one embodiment, the process further comprises step (v) wherein the water phase of step (iv) is recycled in the process by using said water phase as source of water steam in the steam- stripping step (ii). Preferably, the water phase is injected in the form of liquid water phase having a temperature of about 30°C to about 70°C, preferably about 60°C, that is instantly converted in water steam once injected to the high- vacuum conditions of the process. This advantageous embodiment, can not only allow the reduction in the needed water resources to carry out the process but also improve the yield of the at least one compound recovery, in case the water phase after step (iv) comprises any residual amounts of said at least one compound.

[0046] The plant material to be subjected to the process according to the invention can be selected from whole plants, plant aerial parts, stems, leaves, flowers, wood, bark, roots, rhizomes, fruits and fruit pericarps. For instance, at least one plant may belong to the families of Lamiaceae such as Mentha spp., or Thymus spp, Orchidaceae such as Vanilla spp., Rutaceae such as Citrus spp. or Zieria spp., Rosaceae such as Rosa spp., Zingiberaceae such as Elettaria spp. or Elettaria spp., Lauraceae such as Cinnamomum spp., or Daphne spp., Apiaceae such as Carum spp., Asteraceae such as Grindelia spp., Matricaria spp. or Chromolaena spp., Myrtaceae such as Eucalyptus spp., Annonaceae such as Xylopia spp., Brassicaceae such as Lepidium spp., Fabaceae such as Arachis spp., Juglandaceae such as Juglans spp., Vitaceae such as Vitis spp.

[0047] The plant material can used as such or milled. In case milling is considered necessary, may lead to plant material particle size in the range of 2 mm to 0.5 mm. In that case, milling must be done immediately prior to processing so as to avoid the risk of oxidation directly after milling. According to one embodiment, the plant material is not dried, thereby facilitating the diffusion of the at least one compound to the surface of the plant material during the process of the invention. In case the plant material is supplied in its dried form, the process may comprise a step of hydrating the dried plant material prior the high-vacuum process according to the invention.

[0048] According to a preferred embodiment, the at least one compound and/or the plant material are odorous.

[0049] The at least one compound, preferably the at least one odorous compound (or fragrance compound), that can be recovered from a plant material according to the invention can be selected from the group consisting of alcohols, phenols, esters, shortchain fatty acids, unsaturated terpenes and terpene oxides, preferably said at least one compound to be recovered presenting a molecular weight of less or equal than 300 g/mol, preferably less or equal than 250 g/mol, even more preferably less or equal than 200 g/mol, still more preferably less than 160 g/mol.

[0050] As defined above, the at least one compound is steam- volatile, preferably steamvolatile under the high vacuum conditions according to the invention. Typically, steamvolatile compounds can be diffused in the plant material and carried away from the plant material by the high-vacuum water steam such as for example by forming hydrogen bonds with the high-vacuum water steam. [0051] In one embodiment, the at least one compound is at least one compound of an essential oil. According to an advantageous aspect of the invention, the water steam under the high vacuum conditions of the process selectively carries-away the at least one compound that is steam volatile as defined above, without recovering undesired molecules such as lignans, tannins or saponosides, that present a molecular weight of more than 300 g/mol and/or that cannot form sufficient hydrogen bonding with the high vacuum water steam so as to be recovered from the plant material.

[0052] According to an exemplary embodiment, the at least one odorous compound is selected from:

Alcohols further selected from:

Geraniol, typically present in the plant material including plant material rich in essential oils of fruits, vegetables, and herbs such as rose oil, citronella, lemongrass, lavender, and other aromatic plants,

Citronellol, typically found in the plant material of leaves and stems of different species of Cymbopogon (lemongrass),

Menthol, found in the plant material of Mentha spp. plants such as mint, Carveol, found in the plant material of spearmint (Mentha spicalap Farmesol, typically found in the plant material of fruits such as peaches, in vegetables such as tomatoes and com, and in herbs such as lemongrass and chamomile, 1,2-butanediol, typically found in the plant material of Vitis vinifera, 2-butanol, typically found in the plant material of Aloe africana, and Cichorium endivia, 2-3butanediol, typically found in the plant material of cocoa butter, in the roots of Ruta graveolens, and sweet com, 2-ethylhexanol, typically found in the plant material of Vitis rotundifolia, and Lonicera japonica,

2-heptanol, typically found in the plant material of Vitis rotundifolia, and Coffea arabica,

Hexanol, typically found in the plant material of Eupatorium cannabinum, and Vitis rotundifolia, Isobutanol, typically found in the plant material of corn grain, 2-methylbutanol, typically found in the plant material of Manilkara zapota and Centella asiatica;

Aldehydes further selected from:

Neral, typically found in the plant material of Thymus sipyleus, and Cinnamomum burmanni,

Citral, typically found in the plant material of Nepeta nepetella, and Grindelia hirsutula,

Citronellal, typically found in the plant material of Xylopia aromatica, and Chromolaena odorata,

Decanal, typically found in the plant material of Citrus spp., along with octanal, citral, and sinensal,

Heptanal, typically found in the plant material of rose oil, 2-methylbutanal, typically found in the plant material of Citrus spp. (orange, lemon), peppermint, and eucalyptus,

Nonanal, typically found in the plant material of corn, tea, ginger, sweet oranges, carrots, and limes,

(E’,E’)-2,4-nonadienal, typically found in the plant material of citrus especially orange and tangerine;

Esters further selected from:

Methyl Acetate, typically found in the plant material of various fruits such as apples, grapes, bananas,

Ethyl butyrate, typically found in the plant material of figs, Citrus spp. such as tangerines, passion fruits, and apples, apricot, bananas, or plums,

Ethyl hexanoate, typically found in the plant material of pineapple, blackberry, apple-peel and strawberry,

Geranyl acetate, typically found in the plant material of Ceylon citronella, palmarosa, lemon grass, petit grain, neroli, geranium, coriander, carrot, Linalyl acetate, typically found in the plant material of bergamot and lavender, Neryl acetate, typically found in the plant material of Citrus spp., Ethyl butanoate typically found in the plant material of Chaenomeles speciosa (Chinese quince), and Psidium guajava (Guava),

Isobutyl butanoate, typically found in the plant material of Zieria murphyi and Mosla chinensis;

Ketones further selected from:

Acetophenone, typically found in the plant material of several fruits and chicory,

Carvone, typically found in the plant material seeds of caraway (Carum carvi), spearmint (Mentha spicata), and dill,

Menthone, typically found in the plant material of essential oils of pennyroyal, peppermint, and geranium,

Camphor, typically found in the plant material of the wood of the camphor laurel,

2.3- butanedione, typically found in the plant material of Psidium guajava, and Coffea arabica,

2.3-pentandione, typically found in the plant material of several fruits, vegetables, nuts and finnish pine,

2-butanone, typically found in the plant material of trees, fruits and vegetables,

2-heptanone, typically found in the plant material of Aloe africana, and Zingiber mioga,

2-hexanone, typically found in the plant material of nuts, cereals, pepper (C. annuum), and cloves,

3-methyl-2-butanone, typically found in the plant material of Aloe africana, and Averrhoa carambola,

4-methyl-2-pentanone, typically found in the plant material of Citrus spp. (orange, lemon), concord grape, roasted peanut and other plant foodstuffs, 2-nonanone, typically found in the plant material of Curcuma amada, and Hedychium spicatum, 2-octanone, typically found in the plant material of Vaccinium macrocarpon, and Aspalathus linearis;

Phenols further selected from:

Carvacrol typically found in the plant material of essential oils of oregano (Origanum spp.), thyme (Thymus spp.), pepperwort (Lepidium spp.), Citrus spp. (in particular wild bergamot),

Vanillin, typically found in the plant material of Vanilla spp., Eugenol, typically found in the plant material of cloves, Thymol, typically found in the plant material of Thymus spp.;

Unsaturated terpenes and oxides thereof further selected from:

Limonene, typically found in the plant material of the rind of citrus fruits, such as lemons, limes, and oranges,

1,8-cineole, typically found in the plant material of Eucalyptus spp.,

Rose oxide, typically found in the plant material of Daphne papyracea, Daphne odora;

Short chain carboxylic acids such as acetate, typically found in found in Vitis rotundifolia, and Cinnamomum burmanni;

And mixtures thereof.

[0053] According to one embodiment, the plant material is selected from mint, spearmint, citrus, anise, cloves and vanilla and the at least one compound is selected from essential oils thereof, preferably comprising menthol, carveol, limonene, anisole, eugenol, and vanillin respectively.

[0054] In one embodiment, the plant material is selected from spearmint, citrus, anise, and cloves and the at least one compound is selected from essential oils thereof, preferably comprising carveol, limonene, anisole, and eugenol respectively.

[0055] In one embodiment, the plant material is selected from spearmint, citrus and cloves and the at least one compound is selected from essential oils thereof, preferably comprising carveol, limonene, and eugenol respectively. [0056] According to a specific embodiment, the plant material is a Mentha spp plant material, preferably Mentha spp aerial parts and the at least one compound is menthol or carveol, more preferably the plant material is Mentha spicata and the at least one compound is carveol. According to a variant, the at least one compound is carveol in association with carvone, wherein the mass ratio of carvone/carveol is less than 35, preferably less that 25 even more preferably less than 20.

[0057] Treatment system

[0058] A last object of the invention is a system suitable for implementing the process according to the present invention.

[0059] Especially, the invention relates to a system comprising:

- A reactor, preferably a columnar recipient, typically an agitating device, presenting a first and a second plane and an optionally heated circumferential surface,

- a chamber surrounding the columnar blending device recipient with means for air- sealing,

- at least one pump for applying high vacuum and a vacuum inlet configured to apply a high vacuum as defined above in the chamber,

- means for injecting water or water steam in the first plane of the columnar recipient,

- means for condensing the injected water steam from the second plane of the columnar recipient into an aqueous composition.

[0060] Typically, the system further comprises means for separating at least one compound from the condensed aqueous composition such as means for crystalizing, filtering means and means for mechanical separation of biphasic systems such as a separatory funnel. According to one embodiment, the system comprises means for recirculating the aqueous phase of the aqueous composition (ie. after crystallization or mechanical separation) to the means for injecting water or water steam in the first plane of the columnar recipient. [0061] In some embodiments, the columnar recipient is a blending device, the blending device being typically a conical blender.

[0062] In some embodiments, the means for air-sealing the chamber are pneumatically operated valves, typically globe-type valves.

[0063] In some embodiments, the means for injecting water steam at the first plane of the columnar blending device are at least one steam nozzle.

[0064] The means for condensing the injected water steam with the at least one compound from the second plane of the columnar blending device are steam condensing means, typically selected from at least one chiller heat exchanger as described above.

[0065] In some embodiments, the means for condensing the injected water steam are configured between the second plane of the columnar blending device and the pump inlet.

[0066] In some embodiments, the system further comprises means for controlling the temperature, the pressure, the water flow and/or the steam flow, and/or means for filtering the air in the system.

EXAMPLES

[0067] The present invention is further illustrated by the following examples.

Example 1: Fragrance compound recovery from spearmint, citrus, cloves and anise with the process according to the invention

[0068] Carveol and its oxidized form, carvone, have been reported in the essential oil of spearmint. Spearmint essential oil obtained with hydrodistillation typically presents a complex essential oil wherein the carvone/carveol mass ratio is of at least 36 (Chowdhury et al. Chemical Constituents of Essential Oils from Two Types of Spearmint (Mentha spicata L. and M. cardiaca L.) Introduced in Bangladesh, Bangladesh J. Sci. Ind. Res. 42(1), 79-82, 2007).

[0069] The process according to the invention was implemented for the recovery of carveol and carvone from spearmint leaves.

Materials and methods

[0070] In order to assess the carveol recovery from spearmint according to the invention, 970 g of fresh spearmint leaves were milled through a Fritsch mill with a 4 mm sieve. The milled spearmint material was placed into the reactor wherein vacuum was pulled down to 50 mbar. Then the circumferential surface of the reactor was heated at 60°C, and water was injected to the reactor thereby keeping the plant material hydrated under high vacuum for 120 minutes, while the injected water and the recovered fragrance were condensed on a chiller heat exchanger set at 7 °C placed in a round bottom flask communicating with the reactor.

[0071] Samples of the condensate from the chiller heat exchanger were sampled every 30 minutes (about 200ml). To recover the distillate, the round bottom flask was purged with nitrogen until the pressure in the flask equalized and allowed for the condensate to freely flow out of the flask. Condensates 1, 2, 3 and 4 were recovered and analyzed by headspace Gas -chromatography coupled to mass chromatography (HS-GC-MS).

Results

[0072] The HS-GC-MS chromatograms of the condensates 1-4 presented only two peaks with a retention time of 14.73 and 15.07 minutes.

[0073] The MS fragmentation pattern and its comparison with the NIST MS database (NIST Mass spectrometry Data Center, 1990) allowed the identification of the compound eluting at 15.07 min as carveol and the compound eluting at 14.73 min as carvone. The analysis of a commercial spearmint essential oil (Soil, organic spearmint essential oil) under the same HS-GC-MS analysis showed a complex chromatogram that also comprised the peaks of carveol and carvone.

[0074] In order to asses any oxidation effects during the recovery of the spearmint essential oil recovery, the mass ratio of the carvone on carveol was calculated based on the area under the peaks of the HS-GC-MS chromatogram and presented in table 1.

Table 1.

[0075] Interestingly, the carvone/carveol mass ratio of the present condensates ranged from about 16 to about 10, as opposed to the same ratio in the literature (about 36 according to Chowdhury et al. 2007) and as measured in the commercial essential oil (183).

[0076] Using the methods set above, the recovery of at least one fragrance compound from cloves, anise and citrus plant material is ongoing.

[0077] The obtained results with spearmint showed that the present process surprisingly leads to a selective recovery of carveol and carvone from spearmint plant material. Furthermore, considering the measured carvone/carveol mass ratio, the process of the present invention allows the selective recovery of at least one fragrance compound without subjecting it to heat or oxidizing conditions that oxidize it to its oxidized form.