Field of Invention:

The invention relates to a process for the preparation of ready to use jute leaf drink. More specifically the present invention provides a process of manufacturing jute leaf rich in antioxidant suitable for ready to use jute leaf drink .The process involves processing of harvested jute leaves at select parameters followed by subsequent roasting and conversion of jute leaves to a jute leaf drink. Advantageously the present invention provides the especially designed jute leaf drink as a health supplement and preparation method thereof.

Background of Invention:

Jute (Corchorous sp.), the "Golden fibre" is conventionally appreciated in industries for making sacks and coarse cloth. Owing to its biodegradable nature, this fibre is on high demand in replacing synthetic fibre based applications like geotextiles, agrotextiles, carry bags etc. Market trends predict that natural fibres like jute will fetch a "golden era" of global application in near future. Besides the Indian sub-continent, jute is also grown in China and Brazil. The largest importers of raw jute fibre are Germany, Japan, the United Kingdom, Belgium, and France (Ngomuo et al., 2017 International Journal of Agronomy, 6460498: 1-12).

The jute plant, which probably originated on the Indian subcontinent, is an herbaceous annual that grows to an average of 10 to 12 feet (3 to 3.6 metres) in height, with a cylindrical stalk about as thick as a finger (12-18 mm). The two species (Corchorous capsularis and Corchorous olitorius) grown for jute fibre are similar, however, they differ only in the shape of their seed pods, growth habit, and fibre characteristics. Most varieties grow best in well-drained, sandy loam and require warm, humid climates with an average monthly rainfall of at least 3 to 4 inches (7.5 to 10 cm) during the growing season (www.britannica.com). Apart from fibre, the leaves of jute have remained underexploited. Though in West Bengal, India, the young plant twigs (30-40 DAS) are traditionally used as vegetables, but in case of the majority of plants (90-120 DAS) the leaves are shed in the field during harvesting to enrich the soil organic carbon and overall health of the soil. The traditional use indicates the nutraceutical values of jute leaves which remained underexplored.

Jute leaves are 6-10 cm long, 3.5-5 cm broad, elliptic-lanceolate, apically acute or acuminate, glabrous, serrate, the lower serratures on each side prolonged into a filiform appendage over 6 mm long, rounded at the base, 3-5 nerved; petioles 2-2.5 cm long, slightly pubescent, especially towards the apex; atipulessubulate, 6-10 mm long. Leaves are normally light green coloured and are bit bitter in taste. When collected young (30-40DAS), jute leaves are tasty and tender; older leaves tend to be more woody and fibrous, making them less ideal for consumption. In addition to adding a distinctive flavour to food, jute leaves also have nutritional value, and they act as thickeners in soups, stews, and sauces (www.healthbenefitstimes.com).

Constituents of jute leaf

Per 100g of white jute (C. Capsularis) leaves, there is 43-58 calories, 80-84g of water, 4.5-5.6g of protein, 0.3g of fat, 7.6-12.4g of total carbohydrates, 1.7-2.0g of fibre, 2.4g of ash, 266-366mg of calcium, 97-122mg of phosphorus, 7.2-7.7 mg of iron, 12mg of sodium, 444mg of potassium, 6.41- 7.85mg of beta -carotene, 0.13-0.15mg of thiamine, 0.26-0.53mg of riboflavin, l.l-1.2mg of niacin and 53-80mg of ascorbic acid. The folic acid content of jute leaf is comparatively much higher than other folacin-rich vegetables (Islam, 2013 A Review, International Journal of Enhanced Research in Science Technology 8<.Engineering,2(ll): 35-44).

Green leafy vegetables are rich in dietary fibre, vitamins, minerals, betacarotene and ascorbic acid and are hence consumed as food (Banerjee et al., 2012 Journal of Agricultural Technology, 8(4): 1397-1411). Similarly, jute leaves are also consumed as vegetable in various parts of the world. Jute leaf is also called salyuot or ewedu in some parts of the world. It is used as food in the Middle East, Asia and parts of Africa. Jute leaves are rich in carotenoids, dietary fibre, vitamins and minerals (Islam, 2013). Jute leaf is a rich source of flavonoids, glucosides, saponins, triterpenes etc. Various pharmacological studies have revealed that jute possesses antimutagenic, antioxidant, anti-inflammatory, insecticidal and many other such pharmacological properties (Esmail et al., 2016 IOSR Journal of Pharmacy, 6(3): 58-63). Ayurvedics have been using jute leaves for curing ascites, pain, piles and tumors. They are also used for curing cystitis, gonorrhea and fever. Jute leaf is rich in antioxidants. Reactive oxygen species (ROS) and free radicals formed in the body as various metabolic by-products are scavenged by antioxidants (Catherine et al., 1997). A proper balance between the concentration of free radicals and antioxidants ensures the proper functioning of the body. Jute leaves are rich in phenolic compounds. Phenolic compounds possess strong antioxidant properties as they can interact with free radicals since phenolic hydroxyl groups have a strong hydrogen binding ability. The folic acid content in jute leaf is substantially higher than other folacin-rich vegetables (Islam, 2013). Jute leaves also find a number of applications in the field of disease resistance. This green, leafy vegetable is used for maintaining a good eyesight, strong bones and immune system and clear skin. It also provides resistance from a number of diseases like cancer, diabetes, heart disease and hypertension. Ayurvedics use fresh jute leaves as a remedy for pain, piles and tumor (Islam, 2013). However, till now, there is no reported information/protocol for exploitation nutriceutical properties including antioxidant properties of jute leaf or extracts.

The present invention reveals that the jute leaf is rich in antioxidant properties (3/4 ^th of tea leaves) and it has wide arena of DPPH, FRAP and ABTS scavenging properties. A commercial scale protocol has been developed for preparation of jute leaf based drinks (like tea). The farmer friendly approach has opened a new vista for harnessing high value product (as well as healthy materials) from a still considered waste material, like jute leaf.

Market potential:

India has been a habitually affluent in various types of medicinal plants. One such medicinally important plant is jute leaf which is also the significant cash crop in India. Natural products increase the demand (even up to 25% of the prescribed medicines in world) for medicinal plants due to having its regularly effective, safe, affordable traits and having zero side effects. Jute leaf is a source of lots of health-effective chemical compounds that played a key role in the domestic and overseas market world (Anwar, 2011 Golden Fibre Trade Centre Limited. Retrieved September 10; Alim, 1978:A handbook of Bangladesh jute. Effat Begum, 18, Garden Road, Karwan Bazar West, Tejgoan, Dhaka-1215. Bangladesh, pp.1-67; Dempsey, 1975: Fibre crops. The university press of Florida, 15 Northwest 15th Street, Gainesville, Florida 32603. pp. 131-202 and Calleja, 2010 , Inquirer. Retrieved August 7, 2011).

Jute leaves have been used as a food resource in Asia and various parts of Africa. In addition to adding up a discrete aroma to food, jute leaves also have nutritional importance. Jute leaves act as 'roux' in soups, sauces stews. Jute leaves may have different names based upon the area of the cooking like 'saluyot' or 'ewedu' (Annon., 2003; Calleja, 2010). It is possible to grow jute for its fresh leaves in some parts of the world, and some specialty stores also stock it in fresh, frozen, or dried form, depending on their location and size. The leaves are rich in vitamins, micro and macro-nutrients, Vitamin C. Vitamins A, C and E present in jute leaf/Saluyot scavenged free radicals which dig out before they can execute cellular level damage. Plenty of antioxidants in Jute leaf are responsible for chronic diseases such as heart disease, diabetes, cancer, and hypertension etc.

The global nutraceuticals industry valued at US$ 182.6 bn in 2015, is one of the fastest growing industries today and expected to expand at a CAGR of 7.3% from 2015 to 2021. Currently, the United States, Europe and Japan account for most (93%) of the total global nutraceuticals market. The nutraceuticals industry in India is one of the rapid growing markets in the Asia-Pacific region. According to a recent report, the nutraceuticals industry in India is worth about $ 2.2 bn and is projected to grow at 20% to $ 6.1 bn by 2019-2020. (http:// www. nuffoodsspectrum.in/ inner view single details. pho?oaae=l&ontent tvpe= &yrtcl panel nm=& ele id = NOR

588b37ba948df4. 78777381).

The utilization of huge jute leaf biomass (approx. 8-10 t/ha, on green weight basis) will open a new vistas towards increasing farmers income from jute cultivation. Further this project presents jute leaf as a new source of neutraceuticals for human nutrition.

Global tea market was valued at $46,392 million in 2016, and is projected to reach at $67,751 million by 2023, growing at a CAGR of 5.5% from 2017 to 2023. Tea is globally the most popular beverage obtained from Camellia sinensis plant leaves. It offers various health benefits owing to presence of polyphenols working as antioxidants, vitamins, trace minerals, and different amino acids resulting in stronger immunity, lower cholesterol, increased metabolism, prevention of cancer, and more. We apprehend that jute leaf tea constituting same kind of organic components would be an alternative to the traditional available beverages to the consumers. Major population consuming tea has developed it as a habit, subsequently contributing in the growth of the jute leaf tea market.

The global botanical cosmetics market size is projected to reach USD 20.8 billion by 2025, progressing at a CAGR of 6.3% during the forecast period. Skin care products dominated the market in terms of revenue, with a share of over 36.0% in 2017, owing to consumer preferences across diverse regions. The growing popularity of safer and naturally derived cosmetics is anticipated to augment the market and in this context jute leaf extract can play a leading role.

Several prior patents related to jute leaf drink have been summarized hereunder.

CN102349679A (2011) provides Jute functional beverage and preparation method thereof. It prepared a juice of raw jute leaf mainly comprising the components: 10-90% of concentrated juice of edible jute, 2-7% of sweet substance, 0.15-0.30% of citric acid, 0.25-1% of oil, 0.05-0.20% of stabilizer and the balance of water, wherein the total percent of the components is 100%.

CN 102406015A(2011) provides Jute leaf health tea and preparation method thereof. Jute leaf health tea prepared by picking fresh jute leaves and then spread-airing, steaming, entwisting and rubbing, frying, forming, drying and packaging. It discloses two times heating.

CN 1025244786 (2012) discloses Jute tea, preparation method thereof and application thereof in food preparation. Jute leaf health tea prepared by picking fresh jute leaves and then spread-airing, steaming, frying (150-200°C, 1-2 min and cool down to 30-40°C, and repeat 5-6 times), forming, drying (90-130°C, 20-25 min 8i repeat) and packaging. Total operation time is > 35 min. and rrepeated (5-6 times) heating and cooling of leaf.

CN 1038920046(2014) discloses a kind of preparation method growing fruit jute tea, Jute leaf health tea prepared by picking fresh jute leaves and then frying (250-300°C, 20-30 min), grinding and packaging. Processing time 20- 30 min. High temperature 250-300°C

CN109007178A(2018) involves fresh tender leaf of jute pre-treatment (sun/air dry) brewed (20-30 days at 15-20 °C) rub 8i dry (40-42 °C, 5- 6h) -» pack.

Objects of Invention

It is, thus the basic object of the present invention to provide a process for manufacturing of jute leaf rich in antioxidant suitable for ready to use jute leaf drink.

Another object of the present invention is to provide a process for processing the jute leaves involving the steps of the pre processing of the harvested jute leaves, roasting of the processed leaves, cooling of roasted leaves at room temperature and kneading of leaves to obtain the desired size.

Another object of the present invention is provide a process for making ready to use drink from roasted jute leaves.

Yet another object of the present invention is to provide antioxidant enriched jute leaf drink.

Summary of Invention: Thus the basic aspect of the present invention is to provide a process for manufacture of jute leaf rich in antioxidant suitable for ready to use jute leaf drink comprising the steps of:

Pre processing of harvested jute leaves comprising washing and drying at ambient temperature (28±2°C) and rinsing with water and maintaining lower moisture content of up to 4 % . ii. Subjecting the thus washed, dried and moisture controlled jute leaves to selective heating in drying chamber at 180-240 (degree Celsius) for 5-20 minutes. iii. Cooling of roasted leaves at room temperature 25-30 degree Celsius. iv. Kneading of leaves to obtain the desired size and storing.

In another aspect the process of the present invention comprises the steps of said step of pre-processing comprises pre processing of the harvested jute leaves comprising washing with clean water containing 0.1 to 1.5% preferably about 0.5 % sodium bicarbonate solution for 20 to 40 minutes preferably about 30 minutes at ambient temperature (28±2°C) and rinsing the water followed by drying the leaf in shed for 8 to 24 hrs preferably about 12 hrs in semi-shed for desired lowering the moisture content to (4%); iii. said step of selective heating of shed dried leaves in drying chamber at 180-240 (degree Celsius) for 5-20 minutes. iv. said cooling of roasted leaves at room temperature (25-30 degree Celsius). v. said kneading of leaves to obtain the desired size and stored in an air tight container at 65% RH in dark.

Yet another aspect of the present invention provides the process wherein the said step of selective heating is carried out on said pre-processed jute leaves to attain desirable properties including selectively DPPH (85-90%), FRAP (1.2-1.4 mg/g), tannic acid (7-9 mg/g), ascorbic acid (58-62 ppm), total phenolic content (32-35 mg/g) and total chlorophyll (295-300 μg/g ). A still further aspect of the present invention provides the wherein said step of selective heating is carried out for preparation of Jute leaf drink rich in antioxidant activities including DPPH=94.09, TPC=50.00, FRAP=2.47.

A further aspect of the present invention provides the process comprising steps of : i. packing the roasted jute biomass by weighing 1.0- 1.5 g of on a 14.8cm x 8.4 cm sized parchment paper (10-15 GSM) and 0.032-0.036 mm thickness (measured in Prolific thickness gauge) and packed at the rate of 0.8-1 g in a parchment paper bag as a pouch type; and ii. sealing the bag with hot press, clipped with a tag and stored in ambient temperature (28±10C) at 65% RH.

In another aspect the present invention provides the which includes a single step heating of jute leaves at 200-205oC for a period of 10-15 min, followed by sizing (2 mm sieve) at room temperature (28±2°C).

Yet another aspect of the present invention provides Jute leaf rich in antioxidant suitable for ready to use jute leaf drink comprising: roasted jute leaf having selctively DPPH (85-90%) and FRAP (1.2-1.4 mg/g).

A further aspect of the present invention provides the Jute leaf rich in antioxidant comprising tannic acid (7-9 mg/g), ascorbic acid (58-62 ppm), total phenolic content (32-35 mg/g) and total chlorophyll (295-300 μg/g ).

A still further aspect of the present invention provides a process for preparation of Jute leaf drink involving the jute leaf rich in antioxidant of the present invention comprising : i) providing packing the roasted jute biomass by weighing 1.0- 1.5 g of on a 14.8cm x 8.4 cm sized parchment paper (10-15 GSM) and 0.032-0.036 mm thickness (measured in Prolific thickness gauge) and packed at the rate of 0.8-1 g in a parchment paper bag as a pouch type hot press sealed bag which was stored in ambient temperature (28±10C) at 65% RH; ii) providing fresh boiling water (80-100 °C) of 60- 80 ml in a cup and rinsing the pouch for 60 to 120 seconds preferably about 90 seconds to generate a Light greenish yellow colour brew in the water suitable as Jute Leaf drink.

Yet another aspect of the present invention provides the process wherein each said tea bag/ pouch provide for two serving and the same pouch can be dipped in fresh boiling water not more than 90 seconds and repeat the same steps for second serving.

Brief Description of Accompanying Figures:

Figure 1 illustrates Schematic diagram of the process steps of pre processing of Jute leaves.

Figure 2 illustrates changes in different properties of roasted jute leaves with varying temperature and time during roasting. It describes selection of drying temperature and time of jute leaf using response surface methodology (RSM) by utilizing CCD (Central Composite Design). A total of 13 experimental/ design points were developed comprising four cube points, four axial points and five centre points of the CCD.

Figure 3 illustrates that following the Carbon-Hydrogen-Nitrogen-Suphur (CHNS) analysis, the cartoon content in processed jute leaf is 45.1%.

Figure 4 illustrates FTIR analysis for functional groups shows presence of various bonds as indicated by the peaks.

Figure 5 illustrates TGA analysis of processed jute leaf .TG DTA analysis of dried jute leaf reveals the complete removal of moisture at 212°C and no ash is generated at this point. Probably more efficacy of the jute leaves at optimized temperature is due to breakdown of cell components for release of antioxidants. Figure 6 illustrates Liquid-Chromatography Mass Spectrometry (LC-MS) data reveals that more number of compounds peak at around 200°C, which indicated the maximum release of antioxidants.

Figure 7 illustrates compounds peak in LC-MS of 25 bio-active compounds at 200 °C

Detail Description of Invention:

This invention provides to a process or manufacture of jute leaf rich in antioxidant suitable for ready to use jute leaf drink. The present invention provides water based jute leaf drink which has been prepared from the said jute leaves processed at select condition that can yield maximum antioxidant properties.

Unique features of the present invention are :

The present invention describes a novel process to prepare antioxidant enriched Indian tossa jute leaves by a single step heating method for a desirable time.

The innovative step involves heating of prewashed jute leaves at 200-205°C for 10-15min which resulted in development of a processed jute enriched with inbuilt antioxidants.

The processed jute leaves can be used to prepare a ready to use jute leaf drink bag (1g per bag) and antioxidants rich drink can be prepared by dipping the developed bag in hot water (2 serves, 100 ml each) for consumption.

Present invention reveals that the jute leaf is rich in antioxidant properties (3/4 ^th of tea leaves) and it has wide arena of DPPH, FRAP and ABTS scavenging properties. A commercial scale protocol has been developed for preparation of jute leaf based drinks (like tea). The farmer friendly approach has opened a new vista for harnessing high value product (as well as healthy materials) from a still considered waste material, like jute leaf. Protocol for collecting jute leaves:

Leaves from the olitorius (Corchorus olitorius) jute were used for the intended purpose. The leaves were mainly collected from identified villages of North 24 Parganas and Hooghly Districts of West Bengal during the month of May-July in 2019-21.

A protocol has been developed for collecting the jute leaves. Four to five healthy leaves were plucked from standing jute crop intended for fibre or seed purpose. The plants grown for the vegetable purpose, the entire twig portion (12-15") were harvested. Very old and infested leaves were avoided.

Best results obtained from organically grown jute fields.

Following examples describe the invention in detail:

EXAMPLES:

EXAMPLE 1: Steps of processing Jute leaves a) Pre-processing, Cleaning & Shed drying:

Jute leaves collected from the field were initially washed with clean water containing 0.5 % sodium bicarbonate solution for 30 minutes at ambient temperature (28±2°C). After washing, the water was rinsed out and the leaves were shed dried for 12 hrs. The leaves were then dried in semi-shed for another 12 h for lowering the moisture content to (4%) which is essential for storage since more amount of moisture causes further infestation by insects and diseases. When the leaves were dried to make a crackling sound when kneaded, it was stored in an air tight container at 65% relative humidity (RH) in dark. The container was checked periodically to monitor the fungal infection (Fig 1).

Washing in sodium carbonate solution removes the adhered dirt and other externally adhered impurities on the leaf surface by reducing the surface tension on the leaf surface coupled with dissolution in the water. The optimum period of stay at which the maximum removal of externally adhered impurities occurs is 30 minutes. Similarly drying period of 12 hours has been experimented through the monitoring and observation to be the most suitable for the desired processing of jute leaves. b) Procedure for roasting of jute leaves

Pre-treated jute leaves were subjected to roasting under desired temperature (180-240 °C) over a period of time (5-20 min). The effect of these two process variables, temperature and time, on various properties namely, DPPH activity, FRAP activity, tannic acid content, total phenolic content, total chlorophyll content and ascorbic acid content, of roasted jute tea leaves were tested and validated by full factorial central composite design (Fig 2).

The study indicated that above mentioned properties of jute leaves varied with varying temperature and time, which can be shown by following regression equations:

FRAP (mg/g) = 3.3 - 0.029 temp - 0.222 time + 0.000068 temp*temp - 0.00056 time*time + 0.00147 temp*time

DPPH activity (mean % inhibition) = -215 + 3.02 temp + 3.81 time - 0.00739 temp*temp - 0.0101 time*time - 0.0196 temp*time

Tannic acid equivalent (mg/g) = -53.6 + 0.606 temp + 0.781 time - 0.001657 temp*temp - 0.03616 time*time + 0.00087 temp*time

Ascorbic acid equivalent (ppm) = -142 + 1.48 temp - 7.1 time - 0.0037 temp*temp - 0.093 time*time

+ 0.0589 temp*time

Total phenolic content (mg/g) = -493.5 + 5.036 temp + 6.11 time - 0.01282 temp*temp - 0.1962 time*time - 0.00483 temp*time

Total chlorophyll (μg/g) = 6719 - 47.5 temp - 104.4 time + 0.0873 temp*temp + 0.995 time*time + 0.320 temp*time

In this roasting process two major variables namely, temperature and time were selected and a two-level full factorial method of central composite design (CCD) was followed for experiments. The experimental ranges for these variables were as follows: time (5-20 min) and temperature (180-230 OC). The full factorial method of CCD resulted in 13 experiments (4 Cube points, 5 Centre points in cube, 4 Axial points with a of 1.41421) and it resulted in various combinations of temperature and time. The design resulted in only 13 experiments, with interaction effects.

Table 1 : Properties of processed jute leaves under different Roasting Conditions.

The full-factorial method of CCD resulted in 5 experiments at 205 degree and 12.5 mins which are at the centre point of the cube design of the CCD. The observed variation could have resulted from handling errors. However, the 2 factor full-factorial CCD analysis has covered all data and related variations, and they have been statistically validated.

The data shows that under the select roasting conditions(200-205°C for 10- 15mins), processed jute leaves with a set of desirable properties namely, DPPH (85-90%), FRAP (1.2-1.4 mg/g), tannic acid (7-9 mg/g), ascorbic acid (58-62 ppm), total phenolic content (32-35 mg/g) and total chlorophyll (295- 300 μg/g ) can be obtained which are equivalent to other reported plant leaves derived products. The roasted jute leaves are passed through desirable mesh (2 mm) and stored in dark, air tight container at room temperature (28±2 °C) for use. The values of the desired properties were beyond the desirable % when the select roasting conditions were not followed which may be illustrative with the Fig 2.

Storage of roasted jute leaves

The roasted leaves were cooled to ambient temperature (28±1°C) at 65% RH and kneaded further to achieve the desired size of 2 mm sieve and stored in an air tight container in dark.

The storage of roasted leaves at 28±1°C and 65% RH has been selected based non-significant change in the bio-functional activities of the processed leaves over a period of 6 months. Further, air tight condition is required to retard the oxidation of various bio-functional compounds consisting of polyphenols, flavones and aroma compounds of the processed leaves. Otherwise atmospheric oxidation may lead to degradation of the bio-active compounds which may lead to poor quality of the leave.

Roasting of jute leaves under the select conditions give highest quality of roasted jute leaf for preparation of drink purpose.

EXAMPLE 2: Preparation of jute leaf drink:

Preparation of jute leaf drink involves the following steps.

Step 1 -Roasted jute biomass is processed further by weighing 1.0- 1.5 g of on a 14.8cm x 8.4 cm sized parchment paper (10-15 GSM) and 0.032-0.036 mm thickness (measured in Prolific thickness gauge). The bag is further sealed with hot press, clipped with a tag and stored in ambient temperature (28±10C) at 65% RH.

Step 2 - Fresh boiling water (at 100 °C) of 60- 80 ml are taken in a cup and rinsed the pouch for 90 seconds. Light greenish yellow colour brew is released in the water. Step 3 - The tea bag/ pouch prepared are suitable for two serving. Dip the pouch in water not more than 90 seconds and repeat the same steps for second serving.

EXAMPLE 3: Characterization of processed jute leaves

Stored jute leaves were taken and 2 factor analysis was done following response surface methodology (RSM) by utilizing CCD (Central Composite Design). A total of 13 experimental/ design points were developed comprising four cube points, four axial points and five centre points of the CCD.

In the present invention the developed protocol has resulted in the production of jute leaf drink (JLD) with a yield of 30.8%.

Following the Carbon-Hydrogen-Nitrogen-Suphur (CHNS) analysis, the carbon content in processed jute leaf is 45.1% (Fig 3).

With the ICP (Inductively Coupled Plasma emission spectroscopy) the analysis processed jute leaf showed the presence of following elements (Fig 4) .

TABLE 2: Analysis of processed Jute leaf.

FTIR analysis(Fig 4) for functional groups shows presence of various bonds as indicated by the peaks at 1695 cm' ¹ (for residual aldehydes/ketones), 1552 cm ^-1 (for residual aromatic rings in the carbon layer), and at around 1300-900 cm ^-1 (a very strong broad band with its maxima at 1152 cm' ¹ ) are found as the characteristic peaks. Several functional groups of the raw jute stick must have degraded during the high temperature drying process, which is indicated by the shifting of signals under the broad peak at around 1300-900 cm' ¹ . These are associated with oxidised carbons, e.g. C-0 in acids, esters, ethers, phenols etc..

DPPH assay

DPPH assays are widely used methods for the assessment of the antioxidant capacities of natural products, it is spectrophotometric technique based on quenching of stable coloured radicals (ABTS» ⁺ ) and show the radical scavenging ability of antioxidants even when present in complex biological mixtures such as plant or food extracts. The antioxidant activity of the extracts, on the basis of the scavenging activity of the stable 1, 1- diphenyl-2-picrylhydrazyl (DPPH) free radical, was determined by the method described by Braca et al. (2001).

Upon 13 jute leaf tea samples, 40 μg/ml Concentration of jute leaf tea extract showed 24.92 -93.52 % DPPH radical scavenging activity, 80 μg/ml Concentration of jute leaf tea extract showed 36.41 - 92.05 % DPPH radical scavenging activity, 120 μg/ml Concentration of jute leaf tea extract showed 44.53 - 94.55 % DPPH radical scavenging activity, 160 μg/ml Concentration of jute leaf tea extract showed 48.17 - 94.80 % DPPH radical scavenging activity, 200 μg/ml Concentration of jute leaf tea extract showed 52.94 - 96.31 % DPPH radical scavenging activity.

Dasgupta et al., 2004 reported the DPPH radical scavenging activity Piper beetle L. leaf extract 30.6 - 91.2%. Jungmin Oh et al., 2013 reported that DPPH radical scavenging activity of green tea was 82.54%, black tea was 66.65%.

Thus the roasting process of the present invention has achieved the DPPH level similar to the range of tea leaves.

Total Phenolic Content

Total Phenolic Content (TPC) activity is the process to figure out the amount of phenolic content in the samples. Phenolic compounds that contained in the plants have redox properties, and the properties allow them acting as antioxidants The Folin-Ciocalteu test was chosen to measure TPC of jute leaf tea extracts.

Upon 5 jute leaf tea samples, the total Phenolic Content (TPC) activity of jute leaf tea leave extract were 475 -675 mg GAE/100 g. Chan et. AL, 2006 reported the total Phenolic Content (TPC) activity of Young tea leaves were 7280 ± 126, Mature leaves were 5836 ± 294 mg GAE/100 g.

Liquid Chromatography-Mass Spectrometry (LC-MS) analysis of Jute leaf

Jute leaf water extract was subjected to chromatographic analysis through LC-MS. It was observed that the number of bio-active compounds varied with varying processing condition like 18 and 11 bio-active compounds were seen in the samples prepared at 150 and 240 0C, where as 25 bio-active compounds were observed at 200 °C (Fig 6). The 25 bio-active compounds were showed in Fig 7 and in the table below. The compound present in the leaf has been enumerated hereunder with their uses and chemical formula:

TABLE 3:

The present invention therefore provides a process for manufacture of jute leaf rich in antioxidant suitable for ready to use jute leaf drink. Pre processing of harvested jute leaves comprising washing and drying at ambient temperature (28±2°C) and rinsing the water and maintaining a lower moisture content of upto 4 % and roasting the said jute leaves in drying chamber at 180-240 (degree Celsius) for 5-20 minutes are responsible for achieving the jute leaves with high antioxidant levels and finally this results in antioxidant enrichment in the jute leaf drink. If the selected parameters are not followed, obviously the antioxidant properties of the jute leaves will be reduced as revealed by the CCD model .