JP2019037216A - Production method of raw material green tea for beverage - Google Patents

Abstract

To provide green tea excellent in production efficiency and having a high extraction rate as a raw material for green tea beverage compared to a conventional production method of green tea, and to provide a production method of the same.SOLUTION: A production method of green tea includes: (A) a wilting step at room temperature for reducing the moisture content of raw tea leaves to 70-50%; (B) a roasting and steaming step for inactivating oxidative enzyme of the raw tea leaves; (C) a first drying step of exposing tea leaves to hot wind at 50-150°C so as to reduce the moisture content to 65-30%; (D) a compression pulverization step of shearing and crushing the tea leaves while equalizing a water content distribution in the tea leaves by adding pressure; (E) a disintegrating step of disintegrating the mass of the tea leaves; and (F) a second drying step for reducing the moisture content of the tea leaves to 5% or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing green tea.

  Examples of green tea include sencha, gyokuro, kabusecha, mochi tea, and pot-fried tea. Among them, sencha, gyokuro, and kabusecha are generally manufactured through steaming, rough koji, cocoon twisting, middle mushrooms, refined koji, and drying processes. The quality evaluation of these green teas includes items of shape and color, and the shape is generally twisted and the buds are well aligned, and the color is generally highly rated for dark green or fresh green. Therefore, the conventional green tea is manufactured while the tea leaves are shaped into needles through the above-described steps and, further, to prevent discoloration of the tea leaves due to heat, the increase in tea temperature is suppressed as much as possible. However, in the raw materials for beverages that do not include the shape and color in the evaluation items, all the above steps are not necessarily required, and the method for producing green tea is cheaper and has high production capacity, that is, excellent production efficiency. Is required. Also, since conventional green tea takes time to extract the content components, a method for producing green tea with a higher extraction rate is required as a beverage raw material.

  Broken green tea is a green tea with excellent production efficiency and extraction rate. Broken green tea, for example, as in Patent Document 1, cuts tea leaves that have undergone steaming, coarse koji, and re-drying with a shearing force acting between a rotating blade and a fixed blade and a screen, and dries it. It has a black tea-like appearance. Broken green tea has a shorter manufacturing process than conventional green tea, so it can be manufactured at low cost, and it is finely sheared, so it has an excellent extraction rate. However, since the production of broken green tea requires time for the rough koji process, it is required to reduce the time of this process in order to further increase the production efficiency.

  In addition, green tea produced by the CTC manufacturing method is also excellent in production efficiency and extraction rate, and is expected as a raw material for beverages. The CTC manufacturing method is widely used as a method for manufacturing black tea, and is a known manufacturing method. The production method is applied to green tea. For example, as described in Non-Patent Document 1, CTC green tea is dried with high temperature hot air after steaming, dried and crushed with a rotor vane, and then further crushed with a CTC machine. It is manufactured by drying in a fluidized bed dryer. As the CTC machine roller is used, the sharpness of the blade becomes dull, so the blade is polished accordingly. However, because the CTC machine roller has a special shape, a dedicated polishing machine and polishing technology are required for polishing. Therefore, the difficulty of maintenance is an issue.

  Furthermore, regardless of the CTC manufacturing method, as a method for producing green tea using a CTC machine, a green tea consisting of a cutting process using a mincer made of a cutter and a plate, and a loosening process using a CTC machine like a minced apparatus for meat. A manufacturing method (for example, Patent Document 2) is known. According to this document, this production method can shorten the production process as compared with the conventional green tea, and the tea beverage produced from the obtained green tea is said to have excellent taste and richness. However, this manufacturing method also has a problem in maintenance of the CTC machine as described above.

JP-A-8-9883 JP2016-116477A

The latest technology of illustrated tea production-Manufacturing-, first edition, Shizuoka Prefectural Tea Chamber, March 2016

  As a raw material for beverages, conventional green tea has a drawback in that production cost is high and it takes time to extract contents. As methods for solving these problems, methods for producing broken green tea and CTC green tea are known, but there are problems in terms of cost and maintenance, and improvements are required. This invention solves those subjects, and makes it a subject to provide the green tea which is excellent in production efficiency as a raw material for green tea drinks, and has a high extraction rate, and its manufacturing method.

As a result of intensive studies, the present inventor has found that the above problems can be solved by the following production methods (1) to (9) and green tea produced by the production method.
(1). (A) A wilting step at room temperature for reducing the moisture content of fresh tea leaves to 70-50%, (B) a roasting and steaming step for inactivating the oxidase of fresh tea leaves, and (C) 50-150 A first drying step for exposing tea leaves to hot air of ℃ and reducing the moisture content to 65-30%, and (D) pressing to shear and crush tea leaves while making the water distribution uniform in the tea leaves by applying pressure A method for producing green tea, comprising: a pulverizing step; (E) a pulverizing step for breaking the lump of tea leaves; and (F) a second drying step for reducing the moisture content of the tea leaves to 5% or less.
(2). The manufacturing method of the green tea including the said (B) roasting steaming process, (C) 1st drying process, (D) pressing crushing process, (E) crushing process, and (F) 2nd drying process.
(3). The (B) roasting and steaming step is a step of inactivating the oxidase of fresh tea leaves using the latent heat of steam evaporated from fresh tea leaves while roasting fresh tea leaves in a cylindrical kettle heated to 300-400 ° C. A manufacturing method of (1) and (2).
(4) In the first drying step (C), the tea leaves are exposed to hot air of 50 to 150 ° C. in a wire mesh cylinder, the cylinder is rotated, or the tea leaves are stirred by a scooping hand, and the moisture content of the tea leaves (1) And the manufacturing method of (2) which is a process of reducing to 65-30%.
(5). The manufacturing method of (1) and (2), wherein the (C) first drying step is a step of reducing production cost by reusing the exhaust heat of the (B) roasting and steaming step .
(6). The (D) pressing and pulverizing step is a step of using a pulverizer that performs crushing by shearing or friction with a cutter while applying pressure to tea leaves, such as mincer or rotor vane, for example (1) and (2) ) Manufacturing method.
(7). The (E) crushing step is a step of using a crusher that is composed of two sets of rolls with blades mounted at equal intervals, such as a roll crusher, and rotates so that the blades of each roll mesh. A manufacturing method of (1) and (2).
(8). The manufacturing method of (1) and (2), wherein the (E) crushing step is a step in which crushing is repeated a plurality of times, and drying and sieving are performed after each crushing.
(9). Green tea produced by the production method according to (1) to (8).

  According to the present invention, since rough kneading, twisting, middle moxibustion, and refinement processes are not required, green tea can be produced in a shorter time and at a lower cost than conventional green tea production, and production efficiency can be improved. Furthermore, since the tissue and cells of tea leaves are destroyed by the pressing and grinding step, green tea with a high extraction rate can be produced.

Tea production process flow diagram of the present invention

  The “moisture content” described in the present specification uses a moisture content moisture content.

  As used herein, “tea fresh leaves” refers to tea leaves that have not been heat-treated after harvesting. That is, the fresh tea leaves include not only the tea leaves immediately after harvesting, but also the tea leaves stored in a fresh leaf management machine or refrigerator after harvesting, and the tea leaves after wilt treatment. The fresh tea leaves used in the present invention may be any fresh tea leaves used in any of fermented tea, semi-fermented tea, or non-fermented tea, and are not particularly limited. That is, Camellia sinensis var. sinensis, Camellia sinensis var. Any leaves can be used as long as they are harvested from assamica and related species. Also, for example, any kind of variety such as Yabukita, Sayaka Kaori, or even Midori can be used without limitation. The tea season is not limited to 1 tea, 2 tea, 3 tea, and autumn tea, and fresh tea leaves harvested at any time can be used.

(A) Withering step The withering step in the present invention is a step of withering until the water content is reduced to 70 to 50%, preferably 60 to 50% under the ventilation environment of the harvested tea leaves. By this step, the moisture content of fresh tea leaves is reduced, the time required for the subsequent first drying step can be shortened, and the production cost can be reduced. Although the fresh tea leaves used in this step are as described above, in order to increase the drying efficiency, the fresh tea leaves may be appropriately cut before wilting. In this step, a fresh leaf management machine for storing fresh tea leaves is preferably used, and the temperature environment around the fresh tea leaves during wilting is preferably 10 to 40 ° C., more preferably 20 to 30 ° C., which is room temperature. Ventilation is performed to prevent an increase in the temperature of fresh tea leaves due to breathing, and the ventilation cycle may be continuous ventilation or intermittent ventilation with a certain pause time. Furthermore, ventilation can be performed from arbitrary directions. Moreover, when the environmental temperature is low, warm air of 20 to 40 ° C. may be blown.

(B) Roasting and steaming process The roasting and steaming process in the present invention is a process for completely inactivating the oxidase existing in fresh tea leaves. In this step, the tea leaves are roasted in a cylindrical kettle heated at 200 to 400 ° C., and the oxidase of the fresh tea leaves is inactivated using the latent heat of water vapor evaporated from the fresh tea leaves. In this process, excessive steam inside the kettle is discharged out of the kettle, for example, a cylindrical kettle for roasted leaf machines used in the production of kettle roasted tea, or a Taiwan-type blue killing machine used in the production of semi-fermented tea. A rotary metal cylindrical kettle equipped with a steaming device that can be used can be used, and a furnace heat source can use a gas burner, and the exhaust heat can be used for the subsequent first drying step.

(C) 1st drying process The 1st drying process in this invention is a tea leaf in the subsequent crushing process in order to perform the extrusion by the screw in the subsequent pressing crushing process, crushing by friction, and the shearing by a cutter smoothly. In order to make it easy to break up the lump, the tea leaves are exposed to hot air of 50 to 150 ° C. to reduce the moisture content of the tea leaves. If the water content of the tea leaves is too high in the subsequent pressing and pulverizing step, a large amount of water is squeezed out from the tea leaves, and it tends to be agglomerated after the pressing and pulverizing step, making it difficult to disintegrate. On the contrary, if the moisture content of the tea leaves is too low, the frictional force between the machine and the tea leaves is increased in the squeezing and pulverizing process, and the tea leaves cannot be pushed out and may be clogged inside the machine. Therefore, in this step, the water content is reduced to 65 to 30%, preferably 60 to 40%, more preferably 50 to 40%. In this step, for example, a rotating cylinder made of wire mesh capable of supplying hot air of 50 to 150 ° C. or hot air of 50 to 150 ° C. can be supplied and rotated in the cylinder, such as a steamed leaf processor of Kawasaki Kiko Co., Ltd. A fixed cylinder with leafy hands can be used. In addition, the hot air generator in this step is used to send outside air heated in a furnace using a blower fan and supplied as hot air, as used in a ventilator, regardless of tea production. The exhaust heat of the roasting and steaming process can be reused from the rotary cylindrical furnace in the process through the exhaust heat duct. Moreover, when reusing the exhaust heat of the roasting and steaming step, the outside air can be appropriately supplied to stabilize the hot air temperature.

(D) Press crushing process The press crushing process in the present invention applies pressure in order to eliminate unevenness of drying generated in the first drying process, and produces a beverage while making the water distribution in tea leaves uniform. In order to increase the extraction rate, it is a step of crushing tea leaves. In this step, for example, a mincer for meat grinding can be used. In the mincer, the tea leaves can be sheared by a cutter attached to the screw tip while squeezing the tea leaves by inserting the tea leaves and pushing them out while applying pressure in a certain direction with a screw. In this step, a rotor vane used for black tea production can be used. In the rotor vane, the charged tea leaves are squeezed and crushed by the friction between the plate-like protrusions that are spirally arranged on the rotation axis at regular intervals and the protrusions in the cylinder that are aligned to mesh with the protrusions. can do.

(E) Crushing process In the crushing process in this invention, it is a process of unraveling the lump-shaped tea leaf lump which arose in the said pressing-pulverization process. The tea leaf lump does not easily evaporate the internal moisture as it is, and therefore the tea leaf lump needs to be unwound to perform the subsequent second drying step quickly. In this step, for example, a roll crusher composed of two sets of rolls can be used. Further, blades are attached to each roll at equal intervals, and the two sets of rolls are preferably roll crushers that rotate so that the blades of the respective rolls mesh with each other. It can be appropriately changed depending on the size and moisture content.
Further, in this step, when the moisture content of the tea leaf lump is high and cannot be solved by one crushing, the lump of tea leaf can be unwound by repeating the crushing as appropriate. Furthermore, after each crushing, it can be crushed more quickly by drying and sieving. Drying can be performed by exposing the tea leaves to hot air at 70 to 90 ° C., preferably 80 to 85 ° C., for example, using an air dryer, a net dryer, or a fluidized bed dryer. In sieving, a sieve having an aperture of 2.0 to 5.0 mm is used, and the tea leaves on the sieve are again subjected to crushing, drying and sieving steps. The tea leaves under the sieve are transferred to the second drying process as they are.

(F) Second drying step The second drying step in the present invention is a step of reducing the moisture content of the tea leaves after the crushing step to 5% or less. In this step, the moisture content becomes 5% or less by exposing the tea leaves to hot air at 70 to 90 ° C., preferably 80 to 85 ° C., using, for example, an air dryer, a net dryer, or a fluidized bed dryer. Can be dried.

Example 1
A number of green tea varieties (Kyomidori, Samidori, Asahi, Sayaka Kaori, Abe Ichigo, Goko, Uji Midori) harvested at Fukujuen CHA Amusement Park were mixed and used as ingredients. Fresh tea leaves were put into a fried leaf machine (manufactured by Mori Tea Machine Co., Ltd.) heated to a kettle temperature of 300 ° C., and immediately after the addition, the inlet was closed and steamed. After roasting and steaming, the input port of the fried leaf machine was opened and room temperature outside air was blown into the fried leaf machine to dry the tea leaves so that the water content was 60 to 50%. The dried tea leaves were cooled and pulverized using a manual mincer for grinding meat. After pulverization, the lump of tea leaves turned into a spherical shape was unwound by hand, put into a dryer, and dried at 80 to 85 ° C. to a moisture content of 5% or less.

Example 2
Fresh tea leaves similar to those in Example 1 were put into a 100 kg type fresh leaf management machine (manufactured by Kawasaki Kiko Co., Ltd.), and the outside air at room temperature (26-30 ° C.) was continuously blown for 6 hours. After roasting and steaming, the same procedure as in Example 1 was performed.

Comparative Example Fresh tea leaves similar to those in Example 1 were fried and steamed in the same manner as in Example 1, and then dried in the same manner as in Example 1 through a twister and a re-dryer.

Measurement of extraction rate 10 g of tea leaves were put into a 2000 ml stainless steel beaker, and 1000 ml of boiled deionized water was poured. When 2.5 minutes passed, the mixture was stirred 10 times with a spoon, and when 5 minutes passed, the tea leaves and the extract were separated. The weight of the obtained extract and the amount of soluble solids (Brix value) were measured. The Brix value was measured using a low sugar beverage concentration meter (RX-DD7α-Tea, manufactured by ATAGO). The amount of soluble solids in the extract was calculated from the weight of the extract and the measured Brix value, and the value was divided by the amount of tea leaves used for extraction, and the value was taken as the extraction rate.

Sensory examination 2 g of tea leaves were put in a 200 ml beaker, 200 ml of boiling deionized water was poured, and after extraction for 5 minutes, the tea husk and the extract were separated to obtain an extract. A comparative example was used as a standard, and light blue, aroma, umami, bitter and astringent taste, freshness, concentration, and overall taste were evaluated. For the light blue, the standard score was 5, and the blue one was added, and the red one was reduced. As for aroma, umami, bitterness, and freshness, points that felt strong were scored and those that felt weakly were deducted. Concentrations were scored for those that felt dark, and deducted for those that felt light. In terms of overall taste, according to individual tastes, those that tasted delicious were added, and those that tasted bad were deducted. The sensory examination was conducted by four men and women in charge of product development in the company.

  The extraction rate and sensory examination results are shown in Table 1. According to the results, the green tea (Example 1 and Example 2) manufactured using the green tea manufacturing method of the present invention has an extraction rate compared to the green tea (Comparative Example) manufactured by the conventional manufacturing method. It was excellent. About the light blue color, fragrance, umami, concentration, and overall taste, the product of the present invention was superior to the comparative example. About bitter astringency, compared with the comparative example, it was suppressed a little in Example 1, and was equivalent in Example 2. About freshness, compared with the comparative example, Example 1 was equivalent, and Example 2 was excellent. That is, compared with the comparative example, the product of the present invention has a light blue color, a strong aroma and umami, a strong sense of concentration, a strong bitter taste, and a refreshing quality. It had excellent flavor and a suitable flavor as a raw material for beverages. In addition, comparing Example 1 and Example 2, Example 2 is superior to Example 1 in light blue color, aroma, bitter astringency, freshness, concentration, and overall taste, It has a rich drinking response and an exhilarating ease of drinking, making it an excellent beverage ingredient. Furthermore, in Example 1 and Example 2, compared with the conventional green tea manufacturing method, since a manufacturing process is simple and manufacturing time is short, production cost can be held down. Comparing Example 1 and Example 2, in Example 1, the water content during the pressing and grinding process was high, and the tea leaves were likely to be agglomerated, so the lump of tea leaves could not be completely unraveled in the crushing process. The second drying step took time. On the other hand, in Example 2, natural drying progressed by the wilting process, the moisture content in the crushing process was lower than that in Example 1, and the time required for the crushing process and the second drying process was shorter than that in Example 1. Therefore, the production cost of Example 2 can be further reduced.

  According to the above result, the green tea obtained by this invention had the flavor suitable as a raw material for drinks, and was excellent in the extraction rate. Furthermore, production efficiency can be increased by reducing production costs by simplifying and shortening the manufacturing process.

Claims (9)

(A) A wilting step at room temperature for reducing the moisture content of fresh tea leaves to 70-50%, (B) a roasting and steaming step for inactivating the oxidase of fresh tea leaves, and (C) 50-150 A first drying step for exposing tea leaves to hot air of ℃ and reducing the moisture content to 65-30%, and (D) pressing to shear and crush tea leaves while making the water distribution uniform in the tea leaves by applying pressure A method for producing green tea, comprising: a pulverizing step; (E) a pulverizing step for breaking the lump of tea leaves; and (F) a second drying step for reducing the moisture content of the tea leaves to 5% or less. The manufacturing method of the green tea including the said (B) roasting steaming process, (C) 1st drying process, (D) pressing crushing process, (E) crushing process, and (F) 2nd drying process. The (B) roasting and steaming step is a step of inactivating the oxidase of fresh tea leaves using the latent heat of steam evaporated from fresh tea leaves while roasting fresh tea leaves in a cylindrical kettle heated to 300-400 ° C. 3. The manufacturing method according to claim 1 and claim 2. In the first drying step (C), the tea leaves are exposed to hot air of 50 to 150 ° C. in a wire mesh cylinder, and the water content of the tea leaves is set to 65 to 150 by rotating the cylinder or stirring the tea leaves with a scooping hand. The manufacturing method according to claim 1 or 2, which is a step of reducing to 30%. The manufacturing method according to claim 1 or 2, wherein the (C) first drying step is a step of reducing production cost by reusing the waste heat of the (B) roasting and steaming step. Method. The said (D) pressing crushing process uses the grinder which performs crushing by the shearing by a cutter, or friction, applying pressure to a tea leaf like a mincer or a rotor vane, for example. Production method. The (E) crushing step is a step of using a crusher that is composed of two sets of rolls with blades mounted at equal intervals, such as a roll crusher, and rotates so that the blades of each roll mesh. 3. The manufacturing method according to claim 1 and claim 2. The production method according to claim 1 or 2, wherein the (E) crushing step is a step in which crushing is repeated a plurality of times, and drying and sieving are performed after each crushing. Green tea manufactured with the manufacturing method of Claims 1-8.

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