Title of Invention

A FIELD CONVENIENT JACKETED LEAF INACTIVATOR FOR GREEN TEA PROCESSING

Abstract

A field convenient jacketed leaf inactivator for green tea processing, comprising: a) a treatment tank (1) having a removably fixed external jacket (2), charactersied in that, the said jacket(2) being provided with means (3 inlet ,outlet 4) for thermic fluid, b) the said treatment tank being provided with removably fixable means (5, 6) for charging (5) and discharging (6) of the shoot material, c) a shaft (7) having impellers (9) and material collecting bowls/blades (10) and connected at the center of the said treatment tank, and d) a heating device (13) placed below the said external jacket to heat the thermic fluids.

Full Text

A FIELD CONVENIENT JACKETED LEAF INACTIVATOR FOR GREEN TEA PROCESSING Field of invention The present invention relates to a field convenient jacketed leaf inactivator for green tea processing. More particularly, the present invention relates to a simple, convenient tea leaf roaster to efficiently inactivate the tea shoots to produce good quality green tea having wide range of heating options to enable the operation even in the fields with minimum use of energy. Background and Prior art references ; The present invention is particularly useful during the processing of green tea where the fresh leaf harvested from the bushes of Camellia sinensis (L) O. Kuntze is inactivated/ fixed/ roasted as soon as possible in the field itself. The use of this invention enables the improvement in the quality of the green tea as compared to traditional/ conventional processing methods. The green tea manufactured by using this invention is devoid of smoky or roasted flavour. Other uses of the present invention are that the machine can be utilised to quickly inactivate enzymatic reactions and subsequent drying of herbs as well especially having medicinal or food value, where the biological activities continue for significant period otherwise processed by conventional shade drying which may results in loss of active ingredients. Prior art 1: Most of the green teas manufactured in China are fixed by pan firing. A double roaster fixing machine as shown in figure 1 of the schematic diagram accompanying this specification is used for making Chinese green tea also known as Kamaira-cha. Reference may be made to (i) Shao-Jun Luo. Processing of tea. In: Special issue on tea. Tei Yamanishi (ed.), Marcel Dekker Inc., Hong Kong. Food Reviews International, Vol. 11 (3): 409 - 434,1995, (ii) T. Takeo. Green and 2 semi-fermented teas. In: Tea: Cultivation to consumption. K.C. Wilson and M.N. Clifford (eds.), Chapman & Hall: London, UK, 1992; 413 - 457, wherein the machine is fitted on a frame (1) made up of mild steel (MS) or cast iron (Cl). Tea leaves are placed in the roasting room (2) and start firing in the hearth below roaster (3). The process is continued for 10 - 15 min with agitation of 4 - 5 times/mln. During firing, the greenish odour note is evaporated and the typical pan-fired aroma is developed. After reaching the desired stage, the leaf is removed from the said roasting room by tilting the roaster with the help of transmission system (4) which is operated from switch box (5). The fired leaves are manipulated to one of three shapes characteristic of Chinese green tea during 10-15 min in a roller and dried at 100-150°C in a pan. The products are the gun shot type of tea which is ball-like, the chun-mee and sow-mee types which have a fine, twisted form and the pan-fired type which has a flat leaf form and later polished to a pale white colour. The major drawbacks of this prior art are (i) the temperature of roasting pan initially will be at 250-300°C, as a result the initial charge gets charred/burnt, (ii) because higher temperatures are needed to rapidly heat the leaf/inactive the leaf, there will be very little control to prevent charring / burning. Lower temperature will not inactive the leaf properly resulting in browning of the shoots, (iii) the burnt note of this kind of roasting stays with the end products, (iv) handling of charge per batch is very less viz., 30 kg/batch. Prior art 2: Another method followed for the production of steamed, unshaded green tea in Japan is popularly known as Sen-cha consisting of a series of controlled heating and curling operations. The machinery as shown in figure 2A and 2B of the drawings accompanying this specification is used for the manufacturing of Sen-cha. Reference may be made to T. Takeo. Green and semi-fermented teas. In: 3 Tea: Cultivation to consumption. K.C. Wilson and.M.N. Clifford (eds.), Chapman & Hall: London, UK, 1992; 413 - 457 wherein plucked leaves are steamed for 45 -60 seconds in a steamer (a), then curled and semi-dried in hot-air at 90-110°C for 40-50 min in a primary drying tea roller (b). This primary drying and rolling process reduces the leaf moisture from 76% to about 50%. The leaves are rolled for a further 15 min without heat, and then pressed and dried for 30 - 40 min in hot air at 50 - 60°C in a secondary drying and rolling (c). This secondary drying reduces the moisture content of the tea leaves to about 30%. A further.curling is followed by the third drying stage, in which the tea leaves are dried directly on a hot pan at 80-90°C and twisted for 40 min under pressing and rolling by a curling machine-hand mounted on a pan. Finally, the tea leaves are dried at 80°C until a moisture content of 6% is achieved in final drying and roiling (d). The tea made with these machines, called 'Ara-cha' (=crude tea) in Japan, is produced at a small-holding (1 - 2 ha) farmer's factory or at a factory operated by a farmer's union which involves 50-100 small-holding farmers. This crude tea is refined by the wholesalers because the leaves are not uniform and the product has poor appearance. Therefore, this crude tea is sifted repeatedly to remove stalk and dust formed during the above said series of operations. The refined leaves are dried again to remove the greenish odour note. The major drawback in this method is that the inactivation and further processing involves tedious and elaborative steps for gradual dehydration and rolling. The machinery is also very expensive. Prior art 3: In the drawings accompanying this specification figure 3 represents another method adopted in India for the manufacture of green tea by directly steaming the leaves. Reference may be made to www.workandworks.com. About 200 kg of freshly plucked leaves are charged in to the roasting drum (1) through the doors (2). This roaster is connected to a motor (3) by pulleys (4) and belt (5) system. The roaster is rotated by switching on the motor. Steam generated in a separate boiler Is fed into the roaster through the steam inlets (6) & (7) provided on both sides of the drum. The process of steaming continues for 6 to 7 minutes and within this period the leaves are boiled. If the leaves are not tender (i.e. plucking after 7 days), then roasting time will go up by one minute to one and a half minute. After steaming is completed, the leaves along with the condensed steam are taken out by opening the doors (2). These leaves are dried and then rolled for further processing of green tea. The major drawbacks of direct steaming are (i) the processing area becomes highly wet and unhygienic because of the leaf juice (ii) during rolling, wet leaf loses the soluble ingredients along with extra water present within the leaf due to above, (iii) leaf carries extra moisture due to condensation of the steam injected for inactivation, hence needs to be semi-dried before further rolling, (iv) the loss of useful tea ingredients, the quality of final green tea is inferior as compared to when there is no loss of juice, (v) generation of steam used in the inactivation of leaf and semi drying in point (iii) both results in consumption of extra energy, (vi) the machinery also requires an additional steam generator, (vii) the heavy machinery used in the production requires high capital investment and high recurring costs, thereby, increasing the cost of production. Thus, the machinery and the processes mentioned above have one or the other major drawbacks like (i) inferior quality of green tea, (ii) restricted mode of heating, (iii) narrow, utility in the field, (iv) higher cost of the machinery, (v) unhygienic processing site and (vi) involving wastage of energy. Objects of the invention The main object of the present invention is to provide a field convenient jacketed leaf inactivator for green tea processing, which obviates the drawbacks as detailed above. Another object of the present invention is to quickly inactivate enzyme linked reactions and subsequent drying of herbs which cannot be achieved in conventional air drying under shade condition where the biological activities continue for a significant time during the process and may result in loss of active ingredients. Still another object of the present invention is to provide a portable machinery for the inactivation of green tea leaves and like herbs with wide range of heating options to carry out the processing in adverse site conditions such as without electricity, water etc. Yet another object of the present invention is to provide a machine to make a good quality green tea with minimum use of energy. Summary of the Invention A simple, convenient tea leaf roaster was invented to efficiently inactivate the tea shoots to produce good quality green tea having wide range of heating options to enable the operation even in the fields with minimum use of energy. The invention comprising of roasting tank provided with a heating jacket and an agitator operated manually or by motor. The jacket containing thermic fluid is heated under controlled conditions to generate steam out of the tea shoots charged into the inactivation tank by taking the advantage of moisture present in the fresh two and a bud leaves. The contents in the treatment tank are gently heated up to help in efficient roasting of the leaf without imparting burnt aroma to the end product. The system is designed to have a better control over the working parameters and hence, chances of browning and burning of leaves are minimized. In addition to the inactivation of polyphenol oxidase (PRO), there is a simultaneous loss of moisture from shoots, thus helping conservation of energy. The leaves are completely inactivated without exposing to higher temperature, and due to non-loss of juice from the shoots during the process; the quality of green tea is superior to leaves processed by earlier prior arts. Because of improvement in liquor character, the green teas made by the present invention are likely to have wider consumer acceptability. Brief description of figures Figure 1: Schematic diagram of machinery used for making Chinese green tea. Figure 2: Machinery used for the manufacturing of Sen-cha (steamed, unshaded green tea). Figure 3: Machinery used for the manufacturing of Sen-cha (steamed, unshaded green tea). Figure 4: Machinery India for the manufacture of green tea by directly steaming the leaves. Figure 5: Construction features of the present invention. Figure 6: Construction features of the present invention. Detailed Description of the Invention Accordingly, the present invention provides a field convenient jacketed leaf inactivator for green tea processing, comprising: (a) treatment tank (1) having a removably fixed external jacket (2) connected to a means (3,4) for charging (3) and discharging (4) of thermic fluid; (b) the treatment tank provided with removably fixable means (5, 6) for charging (5) and discharging (6) of the shoot material; (c) a shaft (7) having impellers (9) and material collecting bowls / blades (10) and connected at the center of the treatment tank and (d) a heating device (13) placed below the external jacket to heat the thermic fluids. In an embodiment of the present invention, in (b) the removably fixable means are loose type lids. In another embodiment of the present invention the shaft is fixed on a ball bearing (8) and the impellers and material collecting bowls / blades connected by means selected from the group consisting of nut-bolts, rivets and welding (11). In yet another embodiment of the present invention the shaft is connected to a handle (12) fixed on the shaft to rotate the said impellers for mixing and uniform exposure of material to the heat transfer surface. In still another embodiment of the present invention .the shaft is connected to a motor (14) by known means (15,16) namely 'V'-belt driven (15) on a pulley (16) for mechanization. In another embodiment of the present invention the 'V'-belt is loosened before/ during/after processing of the material to disengage the belt from the shaft. In yet another embodiment of the present invention the treatment tank is provided with means (18) for measuring parameters selected from the group consisting of temperature, humidity and pressure. In still another embodiment of the present invention the external jacket is provided with means (19, 20) for measuring parameters selected from the group consisting of temperature, pressure, thermic fluid regulator and thermic fluid expansion kettle. In another embodiment of the present invention the inactivator is fixed on a stand (21) with wheels (22) for its easy mobility for use in remote areas. In yet another embodiment of the present invention the treatment tank, jacket, shaft, impellers and bowls are made up of metals selected from the group consisting of stainless steel, brass and bronze. In still another embodiment of the present invention the length of the treatment tank, shaft and jacket is extended to operate the system under continuous mode. In another embodiment of the present invention the treatment tank is provided with hoppers at the top extreme one end for feeding and at the opposite end for discharging the material under continuous mode. In yet another embodiment of the present invention at the end of discharging hole rotating blades are fixed for chopping the material before discharging. In still another embodiment of the present invention the material collecting bowls attached to the impellers are fixed with an angle to push the material away from the feeding hopper and towards discharging hole. In another embodiment of the present invention the thermic fluid used in the inactivator is selected from the group consisting of steam, water and heat transfer oils. In yet another embodiment of the present invention the heating means is selected from the group consisting of burners operated on fuel, direct firing by fuel namely wood, briquettes and coal, electric heaters, microwave and ultrasound energy. In still another embodiment of the present invention the external jacket is removable and the treatment tank is heated by above said means. In another embodiment of the present invention the treatment tank is provided with an exhaust fan mounted on a duct for removing the moisture during partial dehydration of the charge. : In yet another embodiment of the present invention continuous charging and discharging is achieved with the use of spiral metal worm of suitable diameter and length. Accordingly the present invention provides a method for inactivation of green tea shoots, said method comprising: (a) filling outer jacket of the roasting tank with water and heating; (b) charging freshly plucked tea shoots comprising two and a bud into the preheated inactivation chamber; (c) continuously mixing the leaves and continuing heating and (d) removing the steamed shoots and cooling the shoots. In another embodiment of the present invention heating is done using heating means, said heating means is selected from the group consisting of burners operated on fuel, direct firing by fuel namely wood, briquettes and coal, electric heaters, microwave and ultrasound energy to provide heat bank. In still another embodiment of the present invention freshly plucked tea shoots in the weight range of 1000 to 7000 g was charged in slowly in the weight range of 100 to 150 g for up to 90 seconds at a time while mixing the leaves to avoid blockage of the impellers and to attain uniform heating. In another embodiment of the present invention the charging lid is closed after complete charging of the shoot. In yet another embodiment of the present invention'the heating is continued for an additional time period of six minutes. In another embodiment of the present invention continuous mixing is achieved by Impellers attached to the shaft, which is rotated by the motor having speed regulator. In still another embodiment of the present invention the temperature of the leaves after inactivation is in the range of 82 to 85 °C. In another embodiment of the present invention the loss in weight in the inactivated leaves is in the range of 150 to 200 g. In yet another embodiment of the present invention the green tea obtained shows no polyphenol oxidase activity and is good in taste without roast flavour. The constructional features of the present invention as shown in the figures 4A and 4B are given below: A stainless steel (SS-304) or brass or any biocompatible material of construction stationery drum/tank (1) having internal diameter.(ID) = 500 - 1000 mm or more; length = 600 - 6000 mm or more; thickness = 3-8 mm primarily serving as a container for holding the material to be inactivated or partially dehydrated. The same tank is fitted with nut-bolts or any appropriate means to a 'MS' jacket (2), ID = 700 - 7000 mm or compatible with the tank, 3.0 - 10.0 mm thickness; covering the bottom half portion of the tank depth = 250 - 3500 mm or as per the dimensions of the tank which will be filled with water/ oil/ thermic fluids from inlet (3) and heated by a heat source (13) consisting of a liquefied petroleum gas (LPG) burner/ stove length = 600 - 6000 mm in V - shape or any convenient shape in one or more parts/pieces connected to one or more LPG cylinders depending upon the length of the tank. The other heating sources that can be used are direct firing, furnace made up of fire clay/ cement and fire bricks, by fuel wood or burners operated with petroleum products or any other source of conventional fuels or heating sources. Water/ oil/ thermic fluids can be drained out from the out let valve (4). To operate the system by steam, the inlet (3) can be connected to a boiler for steam supply and the outlet (4) may be fitted with a steam trapper. Circular, ellipsoidal or any other convenient shape such as square type charging hole (5) having dimensions (L x W) 600 - 6000 mm x 200 - 800 mm with loose-type lid 608 - 6008 mm x 208 - 808 mm and a discharging hole (6) 600 - 6000 mm x 150 - 600 mm along with loose-type lid 608 - 6008 mm x 160 - 808 mm with latch was fixed adjacent to the. charging hole. A shaft (7) having diameter = 25 -100 mm, length = 900 - 6300 mm made up of stainless steel (SS) or brass or any metal, resistant to the processed chemicals/materials used in the manufacture method, fixed at the centre of the axis of the tank longitudinally with the help of ball bearings or any other suitable mechanism (8) of suitable size and compatible with the shaft. On this shaft, impellers (9) of length = 480 - 980 mm of angle iron 50 x 50 - 100 x 100 mm and 5-12 mm thickness fixed preferably at 90° to each other with nut-bolts or studded/ riveted (11). The number of impellers may vary from 2 to 25 or more depending up on length of the tank, quantity of material handled per batch or per hour. The edges of these impellers are welded with paddles in plate bowl shape (10), with length = 300 - 600 mm, depth = 50 - 300 mm leaving 2-5 mm gap from the wall of the tank to mix/ rotate the leaf for uniform exposure to the heat for proper inactivation of the leaf in optimum time by retaining quality. At the one end, the shaft is provided with a handle (12), length = 100 - 300 mm and diameter =25-50 mm to rotate the impellers manually and at the other end a V-belt (15) is connected to a pulley (16) which are fixed on the shaft of the tank and motor (14) to mechanically mix the leaf kept in the tank for inactivation. A system (17) is fitted for V - belt to tighten the latter during processing for effective movement of the shaft without wasting the energy and to loosen after processing for easy discharging of the leaf by rotating the shaft manually, when needed. The motor (14) operating on single phase/ 3 phase, 50 - 60 Hz, 0.5 - 5 hp, with appropriate voltage is also provided with a switch box and reduction box to regulate the rpm of the shaft. Two temperature gauges (18, 19) range 0 - 150°C one each on the roasting tank and in the heating jacket are provided to monitor the temperature of the contents in the tank and thermic fluid in the jacket respectively. A pressure gauge (20) is also provided to monitor the pressure of the jacket. The whole system is fixed on a compatible frame (21) of suitable dimensions along with wheels (22) at the base for easy mobility in the fields. The dimensions viz., length, diameter etc., of the roasting tank (1), jacket (2) shaft (7) and heating source (1.3) may be changed as mentioned earlier to operate the machine in continuous mode by incorporating a leaf charging hopper, having a preferable length = 400 - 800 mm, diameter = 300 - 600 mm with an angle of 20 - 60° at the top left side of the tank and a discharging hole provided at the right hand bottom side of the tank with a provision to cut the discharging material by revolving blades fixed on a shaft which are attached to the pulley by a V - belt which is again connected to the same or other motor of 1.0 - 3.0 hp and a speed regulator. The tank is placed with an angle of 2 - 8° with the base. The paddles/blades on the impellers are removebly fixed with an angle which can be changed from 0 - 90° to move the charged leaf from one end to the other end in required time by exposing all the leaves to the heating surface of the tank. The rpm and the angle of paddles/impellers will be set depending upon the configuration of the machine, load and quality of the end product. The impellers and paddle can also be replaced with a continuous spiral or helical shaped paddles on the shaft or any suitable arrangement which can mix the leaf uniformly and to move the material from charging end to discharging end. The steam is generated out of the leaf itself by taking advantage of moisture present in the fresh shoots of two and a bud. The water jacket provided at the bottom of the tank is heated to its boiling point or slightly above its boiling point to produce wet steam which will gently heat the shoots. The steam formed in the jacket is always wet, saturated and maintained at the same condition to help in roasting the leaves without imparting burnt notes to the end product. The system is designed to have a better control over the working parameters and hence, the chances of browning and burning of leaves are minimized. From the, table 1, analyses of the samples, it is clearly observed that the present innovation helps in effectively inactivating tea shoots without imparting smoky/burnt flavour or aroma to green tea. In addition to the inactivation of polyphenol oxidase (PPO), there is a simultaneous loss of moisture from shoot, thus helping conservation of energy. Due to non-loss of juice from the shoots, the green tea is superior to steam inactivated shoots as described in method 3 of the text. Due to improvement in liquor character, the green teas made from the above inactivation procedure are likely to cater to a wider spectrum of consumers. Fresh tea leaf of 1000 g to 7000 g harvested from the plantation comprising of 40 to 90% two and a bud to be used for the inactivation of PPO were charged in to the roasting tank (1) by manually feeding about 100 g to 150.g at a time. Prior to feeding of the leaf, the inactivator's jacket (2) may be filled with an oil or water as a thermic fluid through the inlet (3) for heating the tank. The tank can be directly heated from the hearth bellow or by firing with the burners (13) operated on petroleum products in the furnace constructed with fire brick and clay/ cement. The temperature of the thermic fluid used may be kept between 90° to 120°C which can be monitored by a thermometer (19) fixed on jacket (2). The temperature of the contents in the inactivation tank (1) is observed from a thermometer (18) provided at the top portion of the tank. Other thermic fluid that can be used is steam, which may be generated in a separate boiler. The motor (14) attached to the shaft (7) by V - belt (15) is switched on to rotate the paddles (10) fixed to the impellers (9) for uniform heating of the leaf to be inactivated. After completion of charging of shoots, the charging hole (5) is closed and the process of heating and mixing Is continued for 4 to 7 minutes to completely inactivate PRO. During the process, the moisture present in the fresh leaves charged is taken out by external heating of the tank walls and the steam generated out of this moisture is further used for inactivation of PRO. After such an inactivation, both the heating and rotation are stopped and leaves are taken out of the tank by opening the discharging hole (6) and by manually rotating the shaft (7) with the help of handle (12). This manual operation is possible only when the V'-belt is disengaged from the pulleys (16) by the arrangement (17) provided. While manually rotating the shaft, the material in the tank is collected in the bowl (10) which is attached to the impellers (9) can be taken out and spread on sieves kept under room fan for rapid cooling of the shots to ambient temperature. After cooling to room temperature, the shoots are weighed on a weighing machine and the moisture losses were calculated. A small fraction of the batch can then be tested/ analysed for its residual PRO activity. The following examples are given by way of illustration of the present invention and therefore should not be construed to limit the scope of the present invention. EXAMPLE -1 The outer jacket of the roasting tank as shown in the figures 4A and 4B was filled with water and heated with LPG gas burner to maintain the steam pressure at 0.8 kg/cm2. Freshly plucked tea shoot (1500 g) comprising of 60% two and a bud were charged into the inactivation chamber: which was pre-heated to 100°C. This 1500 g of leaves was not charged all in one go, but by slowly charging about 100 to 150 g at a time into the tank to avoid blockage of the paddles and to attain uniform heating. The total time taken for charging of shoots was about 50 seconds. The charging lid was closed after complete charging of the shoots. The leaves were continuously mixed with the paddles attached to the shaft which was rotated by a motor having a speed regulator. Heating was continued; with the paddle continuing to rotate, for an additional six minutes. At the end, a few drops of condensed water could be seen coming out of the lid joints. The steamed shoots were then removed from the chamber. The temperature of the shoots at the end of the inactivation was measured to be at 85°C. The inactivated shoots were spread on a wire mesh, kept under room fan, for rapidly cooling the shoots to room temperature. The weight of the cooled shoots was observed to be 1350 g. A sample of the cooled shoots was processed for residual PRO activity. The inactivated shoots were then processed further involving rolling and finally dried in an oven to give the final product 'Green Tea1. EXAMPLE -2 The outer jacket of the tank was filled with water and heated with LPG gas burner to maintain the steam pressure at 0.8 kg per cm2. Freshly plucked tea shoots (3000 g) comprising of 60% two and a bud were charged into the inactivation chamber which was pre-heated to 100°C. This 3000 g of leaves was not charged all in one go, but by slowly charging about 100 to 150 g at a time into the tank to avoid blockage of the paddles and to attain uniform heating. The total time taken for charging of shoots was about 90 seconds. The charging lid was closed after complete charging of the shoots. The leaves were continuously mixed with the paddles attached to the shaft which was rotated by a motor having speed regulator. Heating was continued; with the paddle continuing to rotate, for an additional six minutes. At the end, a few drops of condensed water could be seen coming out of the lid joints. The steamed shoots were then removed from the chamber. The temperature of the shoots at the end of the inactivation was measured to be at 82°C. The inactivated shoots were spread on a wire mesh, kept under room fan, for rapidly cooling the shoots to room temperature. The weight of the cooled shoots was observed to be 2800 g. A sample of the cooled shoots was processed for residual PRO activity. The inactivated shoots were then processed further involving rolling and finally dried in an oven to give the final product 'Green Tea1. The observations of the examples illustrated above along with report on the quality of the tea are tabulated: Table 1: Quality of green tea leaves. (Table Removed) The pplyphenol oxidase (PPO) activity was followed as described by Singh and Ravindranath (Singh, H.P. and Ravindranath, S.D. Occurrence and distribution of PPO activity in floral organs of some standard and local cultivars of tea. J. Sci. Food Agric., 1994, 64: 117-120). Initial activity of PPO in fresh shoots was 1120 unit/g fresh weight. The main advantages of the present invention are: 1. Improves the green tea quality where it is devoid of smoky or roasted flavour. 2. 'Herbal Inactivation: The harvested crops are usually air dried under shade conditions where biological activities continue for a significantly longer time which may result in lose of active ingredients. The present invention will serve to quickly inactivate enzyme linked reactions and subsequent drying of herbs. 3. On improvisation into continuous mode, more charge can be handled per hour. 4. Field convenient, which can be used for small batches to wide range for assessing the suitability of a germplasm for making the quality grade green tea. 5. Improvised machines can be designed and made for use by marginal, medium and big growers for making green tea. 6. The commercial Japanese tea making machines as described in prior art 2 (Fig. 2A and 2B) are big and very expensive involving separate machines for (a) inactivation viz., for fixation or roasting and (b) rolling and semi- drying of the shoot stage-by-stage. In present invention, the above two steps are performed in one step, hence rendering it cost effective. 7. This invention prevents loss of the juice, owing to conversion of shoot into steam, which is otherwise lost by. direct steam inactivation process as followed in prior art 3 (Fig. 3). 8. The factory floor is cleaner and more hygienic when compared to the process involving steam inactivation as is followed in prior art 3 (Fig. 3). 9. The present invention avoids wasteful use of energy involved in steaming and subsequent manufacture. 10. Because of wide range of options available in heating sources/fuels, manual and/or mechanical operation, and size of the unit, it can be used at different location under different operational conditions for inactivation of the leaves. We claim: 1. A field convenient jacketed leaf inactivator for green tea processing, comprising: a) a treatment tank (1) having a removably fixed external jacket (2), charactersied in that, the said jacket(2) being provided with means (3 inlet ,outlet 4) for thermic fluid, b) the said treatment tank being provided with removably fixable means (5, 6) for charging (5) and discharging (6) of the shoot material, c) a shaft (7) having impellers (9) and material collecting bowls/blades (10) and connected at the center of the said treatment tank, and d) a heating device (13) placed below the said external jacket to heat the thermic fluids. 2. An inactivator as claimed in claim 1, wherein in step (b) the removably fixable means are loose type lids. 3. An inactivator as claimed in claim 1 , wherein the shaft is fixed on a ball bearing (8) and the impellers and material collecting bowls / blades connected by nut-bolts, rivets and welding (11). 4. An inactivator as claimed in claim 1, wherein the shaft is connected to a handle (12) fixed on the shaft to rotate the said impellers for mixing and uniform exposure of material to the heat transfer surface. 5. An inactivator as claimed in claim 1, wherein the shaft is connected to a motor (14) by known means (15, 16) such as 'V'-belt driven (15) on a pulley (16). 6. An inactivator as claimed in claim 1, wherein the treatment tank is provided with means (18) and for measuring parameters such as temperature, humidity and pressure. 7. An inactivator as claimed in claim 1, wherein the external jacket is provided with means (19, 20) for measuring parameters such as temperature, pressure, thermic fluid regulator and thermic fluid expansion kettle. 8. An inactivator as claimed in claim 1, wherein the inactivator is fixed on a stand (21) with wheels (22) so as to move in remote areas. 9. An inactivator as claimed in claim 1, wherein the treatment tank, jacket, shaft, impellers and bowls are made up of metals selected from the group consisting of stainless steel, brass and bronze. 10. An inactivator as claimed in claim 1, wherein the length of the treatment tank, shaft and jacket is extended to operate the system under continuous mode. 11. An inactivator as suggested in claim 10, wherein the treatment tank is provided with hoppers at the top extreme one end for feeding and at the opposite end for discharging the material under continuous mode. 12. An inactivator as claimed in claim 10, wherein at the end of discharging hole rotating blades are fixed for chopping the material before discharging. 13. An inactivator as claimed in claim 10, wherein the material collecting bowls attached to the impellers are fixed with an angle to push the material away from the feeding hopper and towards discharging hole. 14. The inactivator as claimed in claim 1, wherein the thermic fluid used in the inactivator is selected from the group consisting of steam, water and heat transfer oils. 15. An inactivator as claimed in claim 1, wherein the external jacket is removable and the treatment tank is heated by above said means. 16. An inactivator as claimed in claim 1, wherein the treatment tank is provided with an exhaust fan mounted on a duct for removing the moisture during partial dehydration of the charge. 17. An inactivator as claimed in claim 1, wherein continuous charging and discharging is achieved with the use of spiral metal worm of suitable diameter and length. 18. A method for inactivation of green tea shoots using the field convenient jacketed leaf inactivator for green tea processing as claimed in claim 1, said method comprising: a) filling outer jacket of the roasting tank with water and heating, (b) charging freshly plucked tea shoots comprising two and a bud into the preheated inactivation chamber, in the weight range of 100 to 150 g for up to 90 seconds at a time while mixing the leaves to avoid blockage of the impellers and to attain uniform heating, (c) continuously mixing the leaves and continuing heating is for an additional time period of six minutes, temperature of the leaves after inactivation is kept in the range of 82 to 85°C.and (d) removing the steamed shoots and cooling the shoots to obtain the green tea obtained shows no polyphenol oxidase activity and is good in taste without roast flavour. 19. A field convenient jacketed leaf inactivator for green tea processing, substantially as herein described with reference to figs 5,6 of the drawings accompanying this specification.

Documents:

2993-DELNP-2006-Abstract-(10-05-2011).pdf

2993-delnp-2006-abstract-(18-05-2010).pdf

2993-delnp-2006-abstract.pdf

2993-DELNP-2006-Claims-(10-05-2011).pdf

2993-delnp-2006-claims-(18-05-2010).pdf

2993-delnp-2006-claims.pdf

2993-delnp-2006-correpondence-1.pdf

2993-DELNP-2006-Correspondence Others-(10-05-2011).pdf

2993-delnp-2006-correspondence-others-(18-05-2010).pdf

2993-delnp-2006-correspondence-others.pdf

2993-delnp-2006-description (complete)-(18-05-2010).pdf

2993-delnp-2006-description (complete).pdf

2993-delnp-2006-drawings-(18-05-2010).pdf

2993-delnp-2006-drawings.pdf

2993-delnp-2006-form-1-(18-05-2010).pdf

2993-delnp-2006-form-1.pdf

2993-delnp-2006-form-18.pdf

2993-delnp-2006-form-2-(18-05-2010).pdf

2993-delnp-2006-form-2.pdf

2993-delnp-2006-form-3.pdf

2993-delnp-2006-form-5.pdf

2993-delnp-2006-pct-210.pdf

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