Title of Invention

A PROCESS FOR THE EXTRACTION AND PROCESSING OF GREEN LEAF SOLIDS.

Abstract The present invention relates to a green tea preparation rich in polyphenols and exhibiting high anti-oxidant activity. The invention also provides a method for preparing the said green tea preparation.
Full Text Field of the invention
The present invention relates to a green tea preparation rich in polyphenols and exhibiting high anti-oxidant activity. The invention also provides a method for preparing the said green tea preparation.
Background of the invention:
Green tea (thea chinensis) is preferred drink in China and other countries of the far-east. It is known that green tea, besides being an enjoyable drink, also displays pharmacological properties which assist in the prevention of and in mitigating diseases in humans and animals. It not only protects the vascular system but also increases the anti-oxidative capacity of the subject.
The anti-oxidative property of green tea is often attributed to the presence of polyphenols in the leaves, especially the epigallactocatechins, to inactivate free radicals.
Currently available tea preparations may contain an element of polyphenols but these preparations are not rich in polyphenols and the same is not readily available to users. Most of these processes have used various enzymes for increasing the tea solubility. An example of such a process is ES 8601658 and CN1318308 leaves are treated with tannase, pectinase, amylase and other cell wall digesting enzymes. A more or less similar process has been followed in US 5,919,500 wherein fermented black tea leaves are co-extracted with water and a cell wall digesting enzyme.
Therefore, in the prior art, enzymes have been used for better extraction, color development and stable instant tea.
However, not enough attention has been paid to retention of polyphenols in the final tea product.
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The prior art which is widely prevalent in processing green tea for conventional tea and instant tea follow the practice of steaming the whole leaf in rotating container where steam is injected to deactivate the enzyme. There are several patents on the manufacture of green tea solids by this method after deactivation it is mascerated and then extracted for solids. The disadvantage in this method is the whole leaf is not properly steamed resulting in either over cooking or leaf going green without steaming. As overcooking will result in damage to the phytochemicals the steaming process is ununiform.
Further, the steamed whole leaf becomes extremely viscous and cannot be mascerated to achieve a proper particle size for proper
extraction to take place.
The steamed green leaf so obtained results in picking up oxygen and getting overfermented during preparation of slurry.
The basic task of the present invention is to avoid the aforementioned drawbacks and provide a tea preparation rich in polyphenols and exhibiting high anti-oxidant activity.
Objects of the Invention:
The main objective of the present invention is to provide a tea
preparation rich in polyphenols and exhibiting high oxidant activity.
Statement of invention.:
Accordingly, the invention provides a tea preparation rich in polyphenols and exhibiting high oxidant activity The said preparation is prepared by following method:
a. Arresting activity of enzymes including polyphenols in green tea
leaves by exposing the leaves to steam for a period of 5-10
minutes,
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b. Preparing a tea leaf slurry by contacting the steamed leaves of
step(a) with an enzyme mix composed of amylase and pectinase
for about 20 to 70 minutes,
c. Pasteurizing the slurry,
d. Polishing the slurry by subjecting it to repeated centrifugation
whereby a centrifugate rich in tea solids is obtained,
e. Evaporating the centrifugate and evaporating it to obtain a tea
preparation containing polyphenols to the extent of 40-45%.
While not wishing to be bound by any theory, it is theoretized that in the prior art processes, when green tea leaves were subjected to maceration with enzymes, the polyphenols being volatile are lost in the early stages of tea preparation itself resulting in a final product wherein these compounds, if present are in minor quantity.
As opposed to these processes, the present invention proposes that
the tea leaves may be cleaned and then immediately subjected to steaming process whereby the activity of enzymes in the tea leaves, including the polyphenols is arrested. Thus, by this step, the polyphenols are preserved in the leaves and retained in the final preparation.
Preferably, the green whole leaf is mascerated and contacted with a medium suitable for brewing containing water softened to remove calcium and magnesium salts.
The water is boiled to 95°C and mixed with the mascer.ated leaf to form a thick slurry which is maintained at high temperature between 90°C to 100°C to deactivate the enzymes responsible for development of polyphenols, i.e. the theaflavins and theaurabigins which causes the tea to develop the color and increase concentration of compounds such as tannins and caffeine. These compounds are undesirable to
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obtain the required balance in the instant green tea with higher content of phytochemicals.
The soft water should be sprayed on the leaf contents in such a manner to ensure that no chemical compound as described above are allowed to develop in this process the contents are to be kept under constant agitation but at the temperature as described above. /This is now transferred to extraction columns which have very slow agitation'-and no heating devices but mainly for brewing the contents
Thereafter, the tea leaves are subjected to treatment with an enzyme mix such as amylase-pectinase at a pH of about 4.5 to 5.5 whereby the tea leaves are allowed to brew along with the enzyme and form a slurry. The process is allowed to continue for about 20 to 70 mirultes with constant stirring. Preferably, the enzyme treatment of the slurry may not exceed 45 minutes. The amount of enzyme added ranges from 0.75% to 1% on the steamed green tea leaf that is mascerated. Preferably the amount is 1%. The extract is concentrated prior to centrifuging to concentrate 10 - 15% solids content. The amount of enzyme in the enzyme mix is 5 to 20 ml.
The slurry so formed is pasteurized by heating to about 90 to 110°C whereby the enzyme mix added earlier is deactivated.
After this step, the slurry is then cooled to room to about 10-20°C and clarified and polished repeatedly to obtain a fine product. At this stage, the insoluble and other unwanted materials are separated from the slurry to produce a fine product.
By the steps of repeated polishing and clarification, unwanted materials in the tea slurry are separated into layers thereby enabling subsequent separation of solid phase and liquid phase.
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In the present invention, gravitational force has been used for phase separation. When a particle moves through a viscous medium under the influence of gravitation, it will attain constant velocity after a certain period of time. This is known as sedimentation velocity. The rate of sedimentation can be calculated with information such as particle diameter, particle density, density of the continuous phase, gravitational acceleration and factors affecting clarification. The larger the particle diameters greater will be the sedimentation rate. The greater the difference in density between the particle and the continuous phase, the greater will be the sedimentation rate. The lower the viscosity of the continuous phase the greater will be the sedimentation rate.
In the present invention, the applicant has used a speed of 6000 to 8000 rpm for centrifugation process to attain a gravitational force or value of 8800 to 13,000 units. It is observed that at this speed and with such gravitational values, the solids are easily separated from the liquid. .
The gravitational values used with respect to the speed of the centrifuge are as under:

R.p.m. of bowl G. value KQ Value
7432 12707 1555
6240 8817 1123
KQ value is used by separator manufacturers and skilled persons to characterize the size of the centrifuge in relation to the capacity and the liquid to be centrifuged and should be used to select the right centrifuge for obtaining accurate results.
It is observed that with increase of the speed of the bowl the gravitational force increases for better clarification as described in the process.
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This step of phase separation or clarification may also be achieved by other methods such as centrifugation or filtration. It has however been found that centrifugation is most effective. The centrifuges used had a RPM of 8800 or more. Generating a 'G' force of 132 times of gravity, further after chilling the extract was further polished and refined in an 8800 RPM centrifuge. The 15% solids were centrifuged at this speed after chilling it to 5°C.
The residue obtained after centrifugation is complete is further processed to eliminate all traces of moisture, say by subjecting it to evaporation and thus, a dry powder rich in polyphenols is obtained. The final product obtained by the process of the invention contains polyphenols as high as 43% as compared to an average 25% or less in other conventional tea extracts. Initially centrifuged at 8% and then concentrated to 10 - 15% solids which stage it is polished at a higher 'G' force has been tried and found to be better on the increase in polyphenol content.
The harsh clarification techniques employed in this process results in an extract which is clarified and contains about 12 -15% solid content; whereas under normal clarification techniques, trie amount of solids present is about 4 - 8%.
The slurry so brewed is separated in decanter centrifuges. The spent material is further extracted again by slurry making with soft water using the counter current technique to obtain higher solids finally for further processing.
Finally, the extract concentration reaches a point of 5 to 8% which has been proved as ideal for obtaining the said results.
The extract is now heated further to a higher temperature to clarify and remove the insoluble matter on centrifuging at a temperature
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between 65°C to 85°C the tannin is removed to a certain extract however this has to be again centrifuged by cooling the tea extract to 2°C to 5°C and holding for a period of 2 hrs prior to centrifuging in machines having a very high 'G' force. To refine and enrich the product and to obtain the desired results this has to be further centrifuged at speeds ranging from 8000 rpm to 12000 rpm this would ensure the product to contain only the desired elements which make it rich in phytochemicals having higher polyphenol content and high anti-oxidant activity.
The beverage may be prepared using the tea solids from this process, which would be 0.35 gms in 100 mis of water. The reconstitution strength is 0.3% v/v.
Antioxidants are substances which prevent or delay the development of an oxidized flavour. It appears that they themselves undergo oxidation and therefore, able to break the chain reaction which occurs during oxidation.
This means a substance which when added to food retards or prevents oxidative deterioration of food. When present naturally or added externally to food they are functional in very small quantities perhaps at levels of 0.01% or less. At higher concentration, they are themselves susceptible to oxidation or they can behave as prooxidants. This can be classified into two groups. l)Primary 2) secondary, the former classified as chain breaking antioxidants, is the material referred in the processing of Instant Green Tea, this can reduce the rate of chain initiation by a variety of mechanisms.
The following examples have been provided to illustrate the invention and not intended to limit the scope of the invention in any manner.
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Experiments:
1, Preparation of green tea powder:
Tea materials i.e the freshly gathered leaves (25 kgs) obtained from Thea chinensis were cleaned and dried. The leaves were immediately subjected to steaming process for about 8 minutes.TJiereafter, 7.5g ml of an enzyme cocktail consisting of amylase and pectinase was added to the steamed mixture of tea leaves and allowed to stand for about 60 minutes.
The slurry was subjected to repeated centrifugation (at least 3 times) at a speed of 8800 rpm. The step was carried out for 25 minutes until a centrifugate rich in catechins was obtained. This centrifugate was dried and the moisture content was minimized by 3.8%. Eventually a dry powder weighing 800 gms was obtained.
This powder was subjected to HPLC test to analyse the contents thereof. It was found that the powder contained the following:
- catechins: 33.0 % by wt - 29.1% by wt
- non-phenols: 42.7% by wt - 41.5% by wt
2. Comparative example:
In order to demonstrate the fact that the tea powder prepared by the process of the present invention contains greater amount of
polyphenols than conventional tea powders, the following experiment was carried out.
0.35 gms of tea powder was dissolved in 100 ml of distilled water at 21°C and a control solution was prepared and was tested for polyphenol content using HPLC method. Similarly, tea powder was prepared as per the process of the present invention and the
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polyphenol content thereof was analysed. The results obtained are provided in the attached comparative table... Explanation for abbreviations

The values shown are the percentage of total polyphenols obtained by following HPLC method. The said method is a standard method used by tea microbiologists and is also a recognized by the Tocklai Tea Research Association Laboratory. The total catechin content is calculated barring caffeine, moisture and Gallic Acid. The total Polyphenol content of any product may also be found using the Ferrous Tartrate Method.
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Polyphenol content of tea prepared by conventional process

Polyphenol content of tea prepared by process of invention



WE CLAIM:
1. A process for preparing a green tea powder enriched in polyphenols,
said process comprising the steps of:
a. Arresting activity of enzymes including polyphenols in green tea
leaves by exposing the leaves to steam for a period of .5-10
minutes,
b. Preparing a tea leaf slurry by contacting the steamed leaves of
step(a) with an enzyme mix composed of amylase and pectinase
for about 20 to 70 minutes,
c. Pasteurizing the slurry in a known manner,
d. Polishing the slurry by subjecting it to repeated centrifugation
whereby a centrifugate rich in tea solids is obtained, and
e. Evaporating the centrifugate and evaporating it to obtain a tea
preparation with polyphenols to the extent of 40-45%.
2. A process as claimed in claim 1, wherein the amount of enzyme in
the enzyme mix is about 5 to 20ml.
3. A process as claimed in claim 1, wherein the slurry is pasteurized
by heating it to 90-110°C.
4. A process as claimed in claim 1, wherein the centrifugate contains
tea solids to the extent of 10-15%.
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5. A process for preparing a green tea powder enriched in
polyphenols, as hereindescribed and illustrated with reference to the
accompanying examples.

The present invention relates to a green tea preparation rich in polyphenols and exhibiting high anti-oxidant activity. The invention also provides a method for preparing the said green tea preparation.

Documents:

00567-kol-2004 abstract.pdf

00567-kol-2004 claims.pdf

00567-kol-2004 correspondence.pdf

00567-kol-2004 description(complete).pdf

00567-kol-2004 form-1.pdf

00567-kol-2004 form-13.pdf

00567-kol-2004 form-18.pdf

00567-kol-2004 form-2.pdf

00567-kol-2004 form-26.pdf

00567-kol-2004 form-3.pdf

00567-kol-2004 form-5.pdf

00567-kol-2004 letters patent.pdf


Patent Number 205522
Indian Patent Application Number 567/KOL/2004
PG Journal Number 14/2007
Publication Date 06-Apr-2007
Grant Date 05-Apr-2007
Date of Filing 15-Sep-2004
Name of Patentee GOODRICKE GROUP LIMITED.
Applicant Address OFFICE AT "CAMELLIA HOUSE",14 GURUSADAY ROAD, KOLKATA 700 019,
Inventors:
# Inventor's Name Inventor's Address
1 DEVARAYAN SIVANARUL BAVAN M/s. INSTANT TEA PLANT, AIBHEEL TEA GARDEN, DISTRICT:-JALPAIGURI,
PCT International Classification Number A 23F 3/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA