JPH0148734B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) This invention relates to a method for producing semi-fermented tea with a new flavor. (Prior Art) Semi-fermented tea is intermediate between fully fermented black tea and edged tea that is not fermented at all, and is mainly produced in China and Taiwan. There are dozens of types of semi-fermented tea, but when divided by degree of fermentation, there are four types: high-grade Taiwanese oolong tea, which is the most highly fermented, followed by Wuyiyan tea, Anxi-style oolong tea, and Taiwanese bao-tung tea, which is the least fermented. It is roughly divided into groups. Semi-fermented tea is usually produced in the following order. (1) Expose the fresh leaves to direct sunlight and wilt them in the sun, turning them over from time to time. (2) Bring them indoors and spread them out in a place where there is no strong ventilation, turn them occasionally and let them wilt indoors. (3) ) When the edges of the fresh leaves turn reddish-brown, put them into a hot kettle and perform ``katairi'' for a few minutes. (4) Roll the leaves for several tens of minutes. (5) Loosen the clumps and dry them thoroughly. The flavor of semi-fermented tea varies considerably depending on the degree of withering and fermentation of the fresh leaves, but it is generally characterized by its excellent aroma. (Problems to be Solved by the Invention) The sun drying in the above production method (1) is carried out for a long period of time depending on the availability, with the degree of drying being adjusted depending on the weather. Therefore, it does not suit the reality of the Japanese tea industry, which aims to process large quantities of tea with a small number of people, and the degree of withering and fermentation is greatly affected by the weather that day, making it difficult to produce tea of uniform quality. In addition, in the above manufacturing method (3), the leaves are roasted for several minutes at a temperature of 150 to 180°C at the bottom of the pot, but it is important to always perform a constant "katari" operation under such high-temperature conditions. is very unfortunate. Because of the above, it is said that the production of semi-fermented tea lacks reproducibility. Furthermore, although the aroma of semi-fermented tea produced by the above manufacturing methods (1) to (5) is generally excellent, some products have a sharp and somewhat pungent aroma. may not necessarily suit the tastes of all Japanese people. Also, because it is ``Kamairi'', there are some products that have a strong burnt aroma that makes it hard to feel the aroma. The purpose of this invention is to compensate for the drawbacks of the semi-fermented tea production methods used in China and Taiwan as described above, and to provide semi-fermented tea with a flavor that suits the tastes of Japanese people. (Means for solving the problem) In order to achieve this object, the present invention has the following configuration. That is, green tea leaves are withered indoors for a long time to reduce their weight by 20-35%. The tea leaves are irradiated and heated with a far-infrared radiator for several tens of minutes to an hour, during which time the leaf temperature is maintained at 30 to 40°C. Collect the tea leaves and continue rolling for 5 to several 10 minutes. Next, the tea leaves are steamed for about 10 seconds using a steam amount of about 200 g per 1 kg of fresh tea leaves. Then loosen the lumps and dry thoroughly. Although the present invention is limited to a far-infrared radiator as described above, substantially the same action and effect as a far-infrared radiator can be expected even if a normal infrared heater is used. (Operation) The operation of this invention will be described in accordance with the order of manufacture. Fresh tea leaves picked from a tea plantation are left in a room without strong ventilation, collected and stirred from time to time, and spread thinly. As time passes, fresh tea leaves wilt, lose moisture, and lose their glossy surface. When the weight loss reaches 20 to 35%, the next step is heat withering using a far-infrared radiator. Tea leaves that have withered indoors are heated with a far-infrared radiator. The surface temperature of the far-infrared radiator should be around 100 to 300℃, which has high heat absorption efficiency for tea leaves, and the temperature of tea leaves should be around 30℃.
Either adjust the distance between the far-infrared radiator and the tea leaves in advance so that the temperature is maintained at ~40℃, or measure the temperature of the tea leaves with a thermometer such as a thermocouple while applying current to the far-infrared radiator. automatically intermittent. As time passes, the leaves further wither, the edges of the tea leaves turn reddish-brown, and they begin to emit a fragrance. Do this for several 10 minutes to an hour. When tea leaves are rapidly withered artificially using hot air or incandescent lamps, the stems, which naturally have a lot of water and are difficult to take away, and the leaves, which have relatively little water and easily absorb heat, There is a big difference in the degree of wilting. However, according to artificial withering using far-infrared emitters,
It can be expected that the difference will become smaller. This is because far-infrared rays are easily absorbed by areas with high moisture content, so heat is easily transmitted to the stems, and as a result, both stems and leaves begin to wither, resulting in uniform withering. Next, the tea leaves are collected and rolled. Twist the tea leaves while applying weight. This twisting operation makes it easier for the catechins in the tea leaves to react with the oxidizing enzyme that oxidizes them, and fermentation progresses rapidly.
The degree of fermentation is proportional to the rolling time, so keep an eye on the fermentation progress for 5 to several 10 minutes. The tea leaves are heated with steam in order to deactivate the oxidative enzymes in the rolled tea leaves and stop fermentation. At this time, the minimum amount of steam and steaming time required to deactivate the enzyme are used. In other words, the amount of steam is per 1 kg of fresh tea leaves.
The weight should be around 200g, and the steaming time should be about 10 to 20 seconds.
If the amount of steam and steaming time are excessive, the aroma components generated during withering may disappear, or the amount of adhering water may increase, resulting in the need for extra heat for drying. After the fermentation is stopped by steaming, the tea leaves are thoroughly dried and finished. By the way, the shape of tea also has commercial value, so it is often shaped into spheres or needles. Therefore, if a certain shape is required, the shape is created using an appropriate shaping means before the final drying operation. The present invention will be explained in more detail using Examples and Test Examples. (Example) Using scissor-picked fresh leaves of varieties (Yabukita, Asagiri, Izumi, Benifuji, Benihomare, Benihikari), tea was made in the following process. Indoor withering → far infrared withering → rolling → steaming → drying Indoor withering was carried out for 10 to 15 hours with the goal of reducing weight by 30 to 35%. Far-infrared withering was performed by irradiating 500 g of fresh tea leaves spread on a 50 x 50 cm wire rope with a far-infrared radiator (30 x 40 cm, 1 KW) from about 40 cm above. Temperature control was performed based on the temperature of the green tea leaves, and the temperature was measured by attaching a thermocouple to the green tea leaves. The kneading was performed for 10 minutes. Steaming was carried out for 10 seconds at a steam rate of 200 g per 1 kg of fresh leaves. Drying is done with hot air at 70℃ until the moisture content of the tea leaves is 5%.
Air drying was carried out until the temperature was about 100%. The above operations are illustrated in FIG. 1, and each operation is explained as follows. The conventional semi-fermented tea production process includes sun-dried withering and roasted leaves, but in the production of this semi-fermented tea, the process has been changed to far-infrared withering and steaming, making it easier to control operating conditions. I made it. Indoor withering is effective in removing grassy odor, and around 12 hours is appropriate as the first step. The conditions for far infrared withering are 40 to 45
℃ for about 60 minutes while stirring every 10 minutes, or for 30 to 40 minutes at 30 to 40℃ for Kamairicha varieties (Izumi) and black tea varieties (Benifuji, Benihonmare, Benihikari). Irradiation was appropriate. Regarding the order of rolling and steaming, it was better to perform rolling first, which resulted in better fermentation and better flavor of the product. (Test Example 1) 3 g of semi-fermented tea was steeped in 180 ml of boiling water for 5 minutes, and the aroma and taste were evaluated using a ranking method. The results are shown in Table 1. In general, black tea varieties produced better products. This is because it has a good aroma, especially No. 10.
Nobeni Hikari has a unique aroma and has been highly praised. On the other hand, the semi-fermented tea produced from Yabukita had no distinctive flavor. During the second tea period, semi-fermented tea was superior in quality to sencha. As a result of a preference survey conducted by Tea Industry Research Center experts using No. 3 Beni Fuji, No. 4 Izumi, and No. 7 Beni Homare, Izumi received 12 votes, Beni Fuji received 8 votes, Benihomare got 2 votes. The reasons why they liked it were that it had a high aroma even though it was steamed, and it had a flowery aroma and oolong tea-like flavor. (Test Example 2) Since the quality of semi-fermented tea largely depends on the quality of the aroma, the aroma components were analyzed. From 100g of semi-fermented tea, essential oils with aromatic components were prepared using vacuum distillation and ether extraction, and gas chromatographic analysis was performed using a PEG-20M capillary column at a temperature increase of 2°C per minute between 70 and 180°C. Summer. The analytical values for each of the two products with the highest and lowest aroma ratings are shown in Table 2. It was observed that products with good quality tended to contain a large amount of linalool oxide (1) and (2). In addition, all products exhibited characteristics of fermented tea, including a high content of cis-3hexen-1-ol, linalool, linalool oxide, geraniol, etc. On the other hand, pyrazines and pyrroles, which are heated aroma components detected in conventional semi-fermented teas, and diasmine lactone, which is common in pouchong teas, were hardly detected. (Effect of the invention) Conventionally, the production of semi-fermented tea has included sun-dried withering and "katari" as described in (1) to (5) above, but in this invention, withering by far infrared rays and steam heat, respectively. Therefore, in the past, it took a long time to obtain the product,
Furthermore, withering and fermentation of tea leaves, which are largely affected by the weather that day, can be done in a short time and without being affected by the weather, and with the effect of far infrared rays, the tea leaves can wither evenly. You can get green tea leaves. In addition, with conventional kettle-frying, the degree of heating of the tea leaves tends to be uneven, making it difficult to obtain a homogeneous product, but according to this invention, steam is used to stop the fermentation of the tea leaves, so the tea leaves are heated evenly. Heating can be achieved. Furthermore, this steaming makes the odor milder and is expected to increase palatability. Many of the tea varieties cultivated in Japan have relatively weak fermentation power. Therefore, they could not expect high quality domestically produced semi-fermented tea. However, in this invention, since the tea leaves are rolled before the steaming operation, fermentation is promoted, and combined with the steaming in the next step, it is possible to produce a unique and excellent flavor. As described above, the present invention is advantageous in that it can compensate for the drawbacks of conventional semi-fermented tea production methods and provide semi-fermented tea with a flavor that suits the tastes of Japanese people.

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【table】 [Brief explanation of drawings]

FIG. 1 shows an overview of an embodiment of the invention. 1... Tea leaves (raw tea leaves), 2... Wire mesh, 3... Far-infrared radiator, 4... Thermocouple, 5... Temperature controller, 6... Rolling machine, 7... Steaming chamber, 8... Steam Supply pipe, 9...net conveyor, 10...dryer.

Claims (1)

[Claims] 1. Wither fresh tea leaves at room temperature for a long time, and then calculate the weight.
Reduce by 20-35%, then use a far infrared radiator for several 10 minutes ~
After irradiating for 1 hour and maintaining the tea temperature at 30 to 40℃, the tea is rolled for 5 to 10 minutes.
A method for producing semi-fermented tea, which is characterized by steaming it for about 10 seconds with a steam amount of about 200g, and finally drying it thoroughly.