JP6180455B2 - Method for producing fermented tea leaves - Google Patents

Description

  The present invention relates to a method for producing fermented tea leaves.

  Tea leaves for extracting tea beverages are roughly classified into non-fermented tea and fermented tea depending on the degree of fermentation. Non-fermented tea leaves are green teas that are produced by steaming so as not to be fermented during the production process. Examples of fermented tea include black tea that is also referred to as fully fermented tea and oolong tea that is also referred to as semi-fermented tea that has a degree of fermentation intermediate between green tea and black tea.

  The fermentation of tea leaves is an important factor that determines the flavor, aroma, color, etc. of tea beverages extracted from tea leaves. Since the degree of fermentation of tea leaves depends on the state of fresh tea leaves and various processing conditions for fermenting the tea leaves, fermentation has conventionally required a lot of labor and time.

  For example, oolong tea leaves are traditionally produced in China or Taiwan. Usually, the raw leaves of tea are sun dried wilt, indoor wilt, rock blue (fermented), slaughtered blue (fried in a pot), twisted, dried. To be manufactured. However, sun-drying is a labor-intensive operation that requires time and labor, and is a difficult operation that is affected by the weather. Also, in rock blue, the fermentation time is not constant due to temperature and humidity, and the quality difference between tea teachers is also large. Therefore, various studies have been made to produce homogeneous fermented tea leaves on an industrial scale. For example, a method of irradiating far-infrared rays to fresh tea leaves without sun light is disclosed (Patent Document 1).

  In addition, when producing fermented tea leaves on an industrial scale, it is difficult to keep the degree of fermentation homogeneous when the amount of tea leaves increases, and it takes a long time to produce tea leaves to achieve homogeneous fermentation. .

JP 62-32843 A

  An object of the present invention is to provide a novel fermented tea leaf production method capable of efficiently producing homogeneous fermented tea leaves on an industrial scale.

As a result of diligent research in view of the problems of the present invention, the present inventors have found that the temperature and moisture content of fresh tea leaves used as raw materials are different, and that variations in these parameters greatly affect the progress and variation in fermentation. It was. Then, by adjusting these parameters to a certain range before fermenting tea leaves, it was found that fermentation of tea leaves can be promoted uniformly even on an industrial scale, and the present invention has been completed.
According to the present invention, the following methods for producing fermented tea leaves can be provided.

1. A hot-air treatment process in which fresh tea leaves are treated with hot air to adjust the temperature of the tea leaves to 15 to 40 ° C. and the dry moisture content of the tea leaves to 200 to 360%;
A method for producing a fermented tea leaf comprising at least a rough koji step in which the tea leaves after the hot air treatment step are crushed by applying pressure while maintaining a temperature suitable for fermentation of the tea leaves.
2. A twisting step of applying pressure to the tea leaves after the rough kneading step;
A middle rice cake process in which the tea leaves after the twisting process are stirred,
The manufacturing method of fermented tea leaves of 1 including the drying process which dries the tea leaves after the said middle rice cake process.
3. The method for producing fermented tea leaves according to 1 or 2, wherein neither sundry wilt nor indoor wilt is performed.
4). The fermented tea leaf according to any one of 1 to 3, wherein the hot air treatment step is performed by charging the tea leaf with hot air while charging the tea leaf into a horizontally-placeable cylindrical container that can rotate the tea leaf. Production method.
5. The manufacturing method of the fermented tea leaves in any one of 1-4 whose temperature of the hot air in the said hot-air treatment process is 60-110 degreeC.
6). The method for producing fermented tea leaves according to any one of 1 to 5, wherein the hot air treatment step is performed for 30 seconds to 5 minutes.
7). The method for producing fermented tea leaves according to any one of 1 to 6, wherein an amount of hot air in the hot air treatment step is 80 to 250 m ³ / min.
8). The time of the hot air treatment process, the temperature of the hot air, and the air volume of the hot air are adjusted depending on the temperature of the fresh leaves of tea to be subjected to the hot air treatment process and the dry moisture reference moisture content. A method for producing fermented tea leaves.
9. 9. The method for producing fermented tea leaves according to any one of 1 to 8, further comprising a processing step of scratching the surface of fresh tea leaves before the hot air treatment step. The method for producing fermented tea leaves according to any one of 1 to 9, further comprising a roasting step of roasting the tea leaves after the drying step after the drying step.
11. Fermented tea leaves produced by the method for producing fermented tea leaves according to any one of 11.1 to 10.
12. A fermented tea beverage comprising a fermented tea extract produced using the fermented tea leaves described in 12.11.
13. Containerized fermented tea beverage comprising the fermented tea beverage according to 13.12.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the novel fermented tea leaf which can manufacture homogeneous fermented tea leaf efficiently on an industrial scale can be provided.

  The method for producing a fermented tea leaf according to the present invention includes a hot air treatment step in which fresh tea leaves are treated with hot air to adjust the temperature of the tea leaves to 15 to 40 ° C. and the dry standard moisture content of the tea leaves to 200 to 360%, It includes at least a rough koji process in which the tea leaves after the hot air treatment process are squeezed by applying pressure while maintaining a temperature suitable for the fermentation of the tea leaves.

  The fermentation of tea leaves is an important factor that determines the flavor, aroma, color, etc. of tea beverages extracted from tea leaves. The degree of tea fermentation depends on the state of fresh tea leaves and various treatments for fermenting them. Varies depending on conditions. According to the method for producing fermented tea leaves of the present invention, the raw tea leaves are treated with hot air before fermentation, and the temperature and moisture content (dry basis moisture content) of the tea leaves are adjusted to a certain range. The fermentation of tea leaves can be started smoothly in the next rough koji process, and the fermentation of tea leaves can be promoted uniformly in the subsequent treatment process. As a result, the time required for producing fermented tea leaves on an industrial scale can be shortened.

  The hot air treatment process and the rough koji process, which are features of the method for producing fermented tea leaves of the present invention, will be described below.

(Hot air treatment process)
In the hot air treatment step, the tea leaves are treated with hot air to adjust the temperature of the tea leaves to 15 to 40 ° C. and the dry water content moisture content of the tea leaves to 200 to 360%. The temperature of the tea leaves is preferably adjusted to 20 to 35 ° C, more preferably 25 to 35 ° C. The dry water content moisture content of tea leaves is preferably adjusted to 250 to 340%, more preferably 260 to 300%.

  In the present invention, the tea leaf temperature and the dry water content moisture content adjusted in the hot air treatment step are the tea leaf temperature and the dry water content water content before being subjected to the subsequent rough koji process, which will be described later, through the hot air treatment process. Let's say rate. In the present invention, the dry water content moisture content of tea leaves refers to the ratio (%) of the weight of water contained in tea leaves before drying to the dry weight of tea leaves.

  The temperature of the tea leaves can be measured at an arbitrary measurement point through the hot air treatment process and the temperature of the tea leaves before being subjected to the next rough koji process. The dry moisture reference moisture content of tea leaves can be determined from the weight of tea leaves before and after drying by sampling a certain amount of tea leaves before being subjected to the next rough koji process through a hot air treatment process. Moreover, it can measure using a commercially available measuring machine, for example, a raw leaf grading machine (Kawasaki Kiko Co., Ltd.).

  By treating the fresh tea leaves with hot air, the moisture of the tea leaves evaporates, the surface of the tea leaves becomes cloudy and loses its luster, and a sweet scent can be exhibited. In addition, by adjusting the temperature of the tea leaves to a certain range, fermentation can be started smoothly in the subsequent steps, and fermentation can be promoted.

  If the temperature and water content (dry water content) of tea leaves are not adequately adjusted, there may be no fragrance like fruit and flowers peculiar to fermented tea, and it may take too much time for fermentation. On the other hand, if the temperature is too high, the fragrance may be blown off or the fermentation may stop. Even when the temperature and moisture content (dry moisture content) of the tea leaves subjected to the hot air treatment process are already within the above predetermined range, the temperature and the temperature within the above predetermined range are treated with hot air. By adjusting the moisture content (dry moisture content), fermentation can be promoted smoothly in the subsequent steps.

  In the method for producing fermented tea leaves of the present invention, the raw tea leaves used as a raw material are from the genus Camellia, such as C.I. sinensis, C.I. It is a fresh tea leaf picked from the tree of assamica (Assamcha) and their hybrids. C. Examples of those belonging to sinensis include, but are not limited to, Yabukita, Yutaka Midori, Sayaka Kaori, Kanaya Midori, Benifuuki, Tsuyu Hikari and the like. The production area of fresh tea leaves (that is, the breeding area of the tree) is not particularly limited, and examples thereof include Japanese production, Chinese production, and Taiwan production.

  Tea leaves are categorized according to the time of their growth, and the ones picked at the beginning of the year are called the most teas, then the second, third, and autumn / winter banchas. The thing is called renewal garden tea. The water content of tea leaves varies depending on the time of growing or picking, and even tea leaves grown or picked at the same time vary depending on conditions such as the growth environment and weather, and these conditions are the same. Even there are variations. In one example, the moisture content of the first tea (dry basis moisture content) is 370%, the moisture content of the second tea (dry basis moisture content) is 320%, the moisture content of the third tea / renewal garden tea (dry basis moisture content) ) Is 280%, and the water content of the autumn / winter bancha (dry water content) is 260%. In addition, the temperature of the tea leaves varies depending on the time of growing or picking, the growing environment, the weather, the storage environment, and the like. The time of the hot air treatment process, the temperature of the hot air, and the air volume of the hot air can be adjusted as appropriate depending on the temperature and moisture content (dry moisture reference moisture content) of fresh tea leaves used in the hot air treatment process. For example, when using Nibancha, which has a relatively high moisture content (dry moisture content), adjust the hot air temperature to lower the hot air volume and compare the moisture content (dry moisture content). When using a small amount of autumn / winter bancha as raw material, the temperature of hot air can be increased to reduce the air volume.

The temperature of the hot air in the hot air treatment step is, for example, 60 to 110 ° C, preferably 70 to 100 ° C, and more preferably 80 to 90 ° C.
The treatment time of the hot air treatment step is, for example, 30 seconds to 5 minutes, preferably 30 seconds to 3 minutes, and more preferably 30 seconds to 1 minute.
Air volume of hot air, for example, a 80~250m ³ / min, preferably from 100 to 250 m ³ / min, more preferably from 150 to 250 ³ / min.

  The hot air treatment step can be performed, for example, by putting the tea leaves into a rotatable horizontal cylindrical container and applying hot air to the tea leaves while rotating the container. The dimensions and the number of rotations of the container can be appropriately determined in consideration of the amount of tea leaves processed, the amount of hot air, and the like.

Moreover, you may further perform the process process which damages the surface of the raw leaf of tea before a hot-air treatment process. This makes it possible to easily adjust the moisture content (dry water content) of fresh tea leaves in the hot air treatment process, and to promote the fermentation of tea leaves in subsequent processes. Moreover, the oxidative fermentation odor produced from the damage | wound attached to the tea leaf can suppress a fragrance, and can provide a suitable fragrance to a fermented tea leaf.
The processing step can be performed, for example, by processing fresh tea leaves with a rotating cutter.

(Roughing process)
In the coarse koji process, the tea leaves after the hot air treatment process are masticated by applying a pressure while maintaining a temperature suitable for the fermentation of the tea leaves. Through this rough koji process, tea leaves can be suitably fermented.
It is known that the temperature suitable for the fermentation of tea leaves is generally 30 to 60 ° C, preferably 40 to 50 ° C. If the temperature becomes too low, the fermentation of tea leaves will not proceed easily, and the time required for producing fermented tea leaves will become long. Moreover, when temperature becomes high too much, fermentation will advance excessively or the oxidase contained in a tea leaf will deactivate and fermentation will stop. Therefore, the temperature of the tea leaves is appropriately adjusted in consideration of the degree of fermentation.

A means for maintaining a temperature suitable for fermentation is not particularly limited, and for example, hot air treatment, heating with a heater, and the like can be performed.
When performing a hot air process, the temperature of a hot air is 70-110 degreeC, for example, Preferably it is 80-105 degreeC, More preferably, it is 90-100 degreeC. The temperature of the hot air, the air volume, and the treatment time can be appropriately determined in consideration of the degree of fermentation of the tea leaves.

  In the rough koji process, the tea leaves are crushed by applying pressure to soften the tea leaves or damage the surface of the tea leaves to promote fermentation. Thereby, the fragrance like the aromatic component of a fruit can be drawn out to a tea leaf.

  The rough koji process can be performed using a leaf cutter or a rough kneader that is usually used in the production of green tea leaves. The leaf punching machine and the roughing machine are, for example, devices equipped with a rotatable arm member (a hand, a leaf blade, etc.) on the central axis of a horizontally-placed cylindrical container. In addition, it has a function of applying pressure to the tea and stirring the tea leaves in the container.

  In the coarse koji process, the fermentation may be stopped when the fermentation of the tea leaves reaches the required degree of fermentation. In order to stop the fermentation, the temperature of the tea leaves may be raised to, for example, 65 to 80 ° C. The temperature of the tea leaves can be raised by, for example, hot air treatment, heating with a heater, or the like. By adjusting the degree of fermentation in the coarse koji process, the obtained fermented tea leaves can be made into oolong tea-like or black tea-like.

  As a conventional method for producing fermented tea leaves, the general methods for producing semi-fermented tea leaves such as oolong tea leaves are plucking, sun-dried wilt, indoor wilt, rock blue (fermentation), slaughtering blue (fried in a kettle), twisting, dipping and drying. It consists of each process. Moreover, the general manufacturing method of completely fermented tea leaves, such as black tea leaves, consists of each process of plucking, wilting, twisting, fermentation, and drying. On the other hand, a general method for producing green tea, which is non-fermented tea, consists of the steps of plucking, steaming, rough koji, twisting, middle mushroom, koji, and drying.

  The method for producing fermented tea leaves of the present invention includes at least a hot air treatment step and a coarse koji step, and steps other than the hot air treatment step and the coarse koji step are arbitrary employed in a conventional method for producing unfermented tea leaves (green tea). A process can be performed. However, in the method for producing unfermented tea leaves, steaming, which is a step of inactivating the oxidase contained in the tea leaves, is not performed. Moreover, although this invention is a manufacturing method of a fermented tea leaf, it does not perform wilt which is the process included in the conventional manufacturing method, specifically, sundry wilt and indoor wilt. Here, in this specification, indoor wilting includes stationary wilting and artificial wilting. The method for producing fermented tea leaves of the present invention performs a hot air treatment step, and adjusts the temperature and moisture content (dry water content) of tea leaves to a certain range, thereby taking time-consuming and labor-intensive sundry wilt. Without performing indoor wilting, the fermentation of tea leaves can be promoted uniformly in the subsequent steps.

  One aspect of the method for producing a fermented tea leaf of the present invention is a hot air treatment step in which fresh tea leaves are treated with hot air to adjust the temperature of the tea leaves to 15 to 40 ° C. and the dry standard moisture content of the tea leaves to 200 to 360%. And the tea leaves after the hot air treatment process, while maintaining a temperature suitable for the fermentation of tea leaves, a rough koji process to apply the pressure, and a twisting process to apply pressure to the tea leaves after the koji process, It includes a middle rice cake process in which the tea leaves after the twisting process are stirred and dried, and a drying process in which the tea leaves after the middle rice cake process are dried.

  Each process other than the hot air treatment process and the rough cocoon process already described will be described below.

(Twisting process)
In the twisting process, pressure is applied to the tea leaves after the rough kneading process. The twisting process can compensate for the lack of stagnation in the rough cocoon process and make the water content of the tea leaves uniform.
The twisting process can be carried out using a twisting machine usually used in the production of green tea leaves. A twisting machine is, for example, a device equipped with a weight in a vertically placed cylindrical or conical container, and has a function of swallowing a tea leaf by rotating the weight while pressing the weight against the tea leaf and applying pressure. .

(Medium process)
In the middle culling process, the tea leaves after the twisting process are agitated and mixed. Further, the tea leaves may be treated with hot air. The tea leaves after the twisting process can be unwound and dried by the intermediate culling process.
The middle rice cake process can be performed using a middle rice cake machine which is usually used in the production of green tea leaves. The intermediate machine is, for example, a device composed of a horizontally-placeable cylindrical container that can rotate, and the inner tea leaves can be agitated by rotating the container. Moreover, you may provide the arm member (a hand, a samurai, etc.) which can rotate on the center axis | shaft of a container. By rotating the arm member, it has a function to apply pressure to the tea leaves and stir the tea leaves in the container and squeeze them in the process, adjusting the moisture by entanglement and transpiration under constant rate drying. Do.

(Drying process)
In the drying process, the tea leaves after the intermediate cocoon process are dried. The drying process can remove excess water from the tea leaves, and by removing the water, the tea leaves can be stored in the storage room until roasting.
For drying, for example, tea leaves may be treated with hot air.

(Roasting process)
You may further perform the roasting process which roasts the tea leaf after a drying process after a drying process. By performing the roasting process, moisture remaining in the fermented tea leaves after the drying process can be evaporated and a fragrant flavor can be imparted.
Although the roasting conditions are not particularly limited, for example, the roasting can be performed at 150 to 200 ° C. for 10 minutes. The roasting process may be repeated a plurality of times.

  The method for producing fermented tea leaves of the present invention can be carried out using a conventional tea leaf production line for green tea. A conventional method for producing green tea consists of the steps of plucking, steaming, rough koji, twisting, middle mushrooms, koji, and drying. Among these processes, the equipment used in the steaming process and the brewing process may simply allow the tea leaves to pass or be short-cut. According to the method for producing fermented tea leaves of the present invention, it becomes possible to produce fermented tea leaves in a conventional green tea production line, so that no investment is required for developing and constructing a new production facility.

(Fermented tea leaves)
The fermented tea leaf of the present invention is produced by the method for producing a fermented tea leaf of the present invention already described.

(Fermented tea drink)
The fermented tea beverage of the present invention contains a fermented tea extract produced using the fermented tea leaves of the present invention already described. A fermented tea extract is extracted from the fermented tea leaves of the present invention, the concentration is adjusted as necessary, and additional optional components can be added to make a fermented tea beverage.

Extraction can be performed by a known method or a method analogous thereto. For example, agitation extraction, kneader extraction, drip extraction, column extraction and the like to which an extraction solvent, an extraction aid and the like are added may be mentioned.
Extraction solvents include aqueous solvents (10 to 100 ° C tap water, pure water, distilled water, desalted water, alkaline ionized water, deep ocean water, ion-exchanged water, deoxygenated water), organic solvents such as ethanol, and aqueous systems. Examples thereof include a mixture of a solvent and an organic solvent, and water is most preferable.

  As an example, the extraction is preferably performed by adding water having a temperature of 70 to 100 ° C. 10 to 50 times by weight with respect to the fermented tea leaves. The extraction time is, for example, 1 to 30 minutes. The fermented tea extract is collected by filtration or the like.

  The additional optional component is not particularly limited as long as it is a component commonly used in beverages. For example, antioxidants, emulsifiers, preservatives, pH adjusters, quality stabilizers, fragrances, dyes, esters, organic acids and salts thereof Inorganic acids and salts thereof, seasonings, sweeteners, acidulants, gums, oils, vitamins, amino acids, fruit juices, fruit extracts, vegetable extracts, flower extracts, and the like. These arbitrary components may contain 1 type and may contain multiple types.

(Container-packed fermented tea beverage)
The container-packed fermented tea beverage of the present invention includes the already described fermented tea beverage of the present invention. It can be produced by packing the fermented tea beverage of the present invention in a container.

  The container can use the same thing as the case of packing a general drink. For example, a molded container (PET bottle) containing polyethylene terephthalate as a main component, a metal can, a paper container combined with a metal foil or a plastic film, a bottle, and the like can be given.

  The container-packed fermented tea beverage of the present invention may be sterilized by a known method. The sterilization treatment may be performed before filling the beverage into the container, or may be performed after filling. Examples of the sterilization treatment method include, but are not limited to, UHT sterilization, retort sterilization, and plate sterilization. If the beverage is sterilized before filling the container, the container may be filled in an aseptic condition.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited to the description of these examples.

Examples 1-4
Using autumn / winter bancha as a raw material, it was subjected to various steps shown in Table 1 to produce fermented tea leaves. In addition, about 5-8 tons of rough tea (tea leaves before a roasting process) were manufactured by Nissan about each Example.

Comparative Example 1
Using Nibancha as a raw material, tea leaves were produced according to a conventional method for producing oolong tea leaves. Specifically, the raw leaves of tea as a raw material were subjected to a wilting process, a biting process, a blue-killing process, a twisting process, a mid-straw process, and a drying process. In the wilting process, movable artificial wilting by ultraviolet and infrared irradiation and indoor standing wilting were performed. About 0.5 tons of crude tea (tea leaves before the roasting process) were produced by Nissan.

Comparative Example 2
Using autumn / winter bancha as a raw material, neither artificial wilting / standing wilting nor hot air treatment process was performed, and tea leaves were produced by the same production method as in Examples 1 to 4 after the coarse koji process. About 7.5 tons of crude tea (tea leaves before the roasting process) were manufactured by Nissan.

  Table 1 shows the details of the production methods of Examples 1 to 4 and Comparative Examples 1 and 2 and the evaluation of the produced fermented tea leaves (raw tea). Evaluation of fermented tea leaves was evaluated according to the evaluation criteria shown in Table 2 for “variation of fermentation” and “flavor / flavor”.

  The fermented tea leaves of Examples 1 to 4 were good as oolong tea leaves in terms of appearance, aroma, and color, and in Examples 3 and 4, the flavor and flavor were particularly suitable. Moreover, when the fermented tea leaves of Examples 1 to 4 were roasted and the fermented tea extract was extracted by a conventional method, the odor, aroma, and color were all good as Oolong tea leaves. There was a good balance between astringency and umami.

  On the other hand, in the fermented tea leaves of Comparative Example 2, the variation in fermentation was large, and both the flavor and flavor were inferior to those of Examples 1 to 4, and the quality was not suitable for commercialization.

  In Examples 1 to 4, the quality of fermented tea leaves is homogeneous and the fermented tea leaves are efficiently produced in a short time even if the production amount is large as compared with Comparative Example 1 which is a conventional method for producing oolong tea leaves. I was able to. In conventional oolong tea production methods, the production amount of fermented tea leaves tends to be constrained by the capacity of equipment used during wilt and fermentation, but according to Examples 1-4, no wilt is performed. It is possible to produce fermented tea leaves on a larger scale than before because the current green tea production line is used without modification, without being restricted by equipment.

According to the method for producing a fermented tea leaf of the present invention, a fermented tea leaf that is homogeneous on an industrial scale can be produced more efficiently than before. In addition, according to the method for producing fermented tea leaves of the present invention, fermented tea leaves can be produced in a conventional green tea production line, so that no investment for developing and constructing a new production facility is required.

Claims (6)

The leaves of the untreated tea is treated with hot air, the temperature of the tea leaves 15 to 40 ° C., and hot air treatment step of adjusting the dry basis moisture content of the tea leaves 200 to 360%,
The tea leaves after the hot-air treatment step, at least including a rough koji step that squeezes by applying pressure while maintaining a temperature suitable for the fermentation of the tea leaves,
The temperature of the hot air in the hot air treatment step is 60 to 110 ° C., and the amount of hot air is 80 to 250 m ³ / min,
The hot air treatment step is performed for 30 seconds to 5 minutes,
A method for producing oolong tea leaves that does not undergo sundry or indoor wilting. A twisting step of applying pressure to the tea leaves after the rough kneading step;
A middle rice cake process in which the tea leaves after the twisting process are stirred,
The method for producing oolong tea leaves according to claim 1, further comprising a drying step of drying the tea leaves after the middle cocoon step.   The hot-air treatment process is performed by charging the tea leaves with hot air while putting the tea leaves into a rotatable horizontal cylindrical container and rotating the containers. Method.   The time of the hot air treatment process, the temperature of the hot air, and the air volume of the hot air are adjusted depending on the temperature of the fresh leaves of tea to be subjected to the hot air treatment process and the dry water reference moisture content. The manufacturing method of Oolong tea leaves as described.   The method for producing oolong tea leaves according to any one of claims 1 to 4, further comprising a processing step of scratching the surface of fresh tea leaves before the hot air treatment step.   The method for producing oolong tea leaves according to any one of claims 1 to 5, further comprising a roasting step of roasting the tea leaves after the drying step after the drying step.