JPH0334894B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF INDUSTRIAL APPLICATION The present invention relates to a method for producing instant tea. In particular, the present invention extracts the soluble flavor components of tea in a well-balanced manner and enhances the flavor of instant tea, which often has a flavor that is inferior to or different from the decoction obtained by conventional tea methods. The present invention relates to a method for producing instant tea having a quality equivalent to that of other tea products. Conventional technology and problems As a method for extracting tea leaves, 10
It is common practice to add about parts by weight of water or warm water and to draw out soluble components by adjusting the soaking time depending on the soaking temperature. However, in the above method, depending on the soaking temperature and soaking time, there is a risk that components such as proteins, caffeine, and tannins may be extracted more than necessary, or that the flavor of the extract may change or deteriorate. . In addition, when instant tea is produced using the above-mentioned extraction method, not only the quality of the resulting product as described above may be affected, but also the long time required for extraction, separation, concentration, drying, etc. This is not only economically disadvantageous, but also causes loss or deterioration of the extracted flavor. Means and Effects for Solving the Problems As a result of research in order to eliminate the drawbacks of the conventional method as described above, the present inventors discovered that by performing the tea extraction process in two stages, namely, the first extraction is carried out in low-temperature water, and the second extraction is carried out at a higher extraction temperature than the first extraction, and at that time, the ratio of water to tea leaves in the second extraction step is lower than that in the first extraction step, It has been found that soluble flavor components can be extracted in a well-balanced manner, and as a result, it is possible to produce instant tea that is comparable in flavor and other aspects to the decoction obtained by ordinary tea ceremony methods. According to the invention, therefore, the first extraction of tea leaves is carried out in low-temperature water, and after adding new tea leaves without separating the extracted tea leaves to reduce the ratio of water to tea leaves, Production of instant tea, characterized by performing a second extraction of tea leaves at a higher extraction temperature than the first extraction, and then adding a substance having flavor retention to the extract obtained by separating the tea leaves, followed by drying. A method is provided. In the method of the present invention, various tea leaves can be used as raw materials, such as non-fermented tea such as green tea, fermented tea such as black tea, or semi-fermented tea such as oolong tea. The first extraction step in the process of the invention is carried out in water at a low temperature, usually between 5 and 30°C. At such temperatures, it takes time to extract soluble components, so in order to increase the extraction rate and shorten the extraction time as much as possible, it is preferable to carry out the extraction operation using a large amount of water. That is, this extraction step is usually carried out using 5 to 20 parts by weight, for example 14 parts by weight, of water per part by weight of tea leaves. The extraction time varies depending on the type of tea leaves, extraction temperature, amount of water used for extraction, etc., but is usually 5 to 30 minutes. After the first extraction step is completed, the second extraction step is subsequently carried out in the method of the present invention, and this extraction step is performed using water (hot water) at a higher temperature than the first extraction step, usually at a temperature of 40 to 90°C. It takes place inside. As mentioned above, the second extraction step uses a smaller proportion of water than the first extraction step, that is, usually 3 to 10 parts by weight of water, for example 7 parts by weight, per 1 part by weight of tea leaves. will be carried out. As mentioned above, the water ratio is adjusted by adding the required amount of new tea leaves to the extract obtained from this step after the first extraction, without separating or removing the extracted tea leaves. This is done by adding The time required for the second extraction step also varies depending on various other conditions in this step, but is usually 5 to 30 minutes. The extract obtained in this way has a flavor completely equivalent to that of the decoction obtained by the ordinary tea ceremony method. Although the desired product can be obtained by immediately drying this extract (Bx = 3 to 5; Bx means the concentration of extracted components), in the present invention, the concentration is as low as possible. In order to minimize the dissipation of flavor components during the drying process, the extract is quickly cooled and then a substance that retains flavor or prevents flavor dissipation, such as dextrin (usually with a DE of 3 to 20), is added to the extract. Add
After preparing the Bx6 to Bx9 formulations, this is dried. Dextrin is usually used in an amount equivalent to that of tea extract. In addition to the above-mentioned dextrin, substances having the same effect as the above-mentioned dextrin, such as Kona candy, may also be used. Drying of the extract is usually performed by spray drying or freeze drying. As is clear from the test results shown in the Examples below, the instant tea obtained by the method of the present invention has a clearly superior flavor compared to a product obtained by performing extraction in one step in low or high temperature water. However, if the extract is immediately dried according to the method of the present invention, it is not only uneconomical because the amount of liquid to be dried is large, but also bulky powder is obtained, and moisture absorption and deterioration occur quickly during storage. I have a sexual problem. It is therefore advantageous to concentrate the extract before drying to increase its concentration. Possible methods for increasing the concentration include vacuum concentration and membrane concentration. However, in the case of tea leaf extracts, preservation of flavor is a very important requirement, so it is necessary to satisfy the condition of concentrating to an economical concentration as well as the condition of not dissipating the flavor as much as possible during concentration. required. The present inventors adopted a method of partial concentration as a method to satisfy these conditions, and as a result, the extract was reduced to an economical concentration without substantially impairing the flavor of the extract (undiluted solution). succeeded in concentrating it. Therefore, according to the invention, it is further provided that after the first extraction of the tea leaves is carried out in cold water and the water to tea ratio is reduced by adding fresh tea leaves without separating the extracted tea leaves, , a second extraction of the tea leaves is carried out at a higher extraction temperature than the first extraction, and then the tea leaves are separated, a substance having flavor retaining properties is added to the obtained extract, a part of the extract is concentrated, and the obtained extract is extracted. There is provided a method for producing instant tea, characterized in that the concentrated liquid obtained is mixed with the remainder of the extracted liquid and then dried. In the second invention of the present invention, a two-stage extraction process is performed under exactly the same conditions as the first invention to obtain an extract (Bx = 3 to 5), and then the first
By adding a substance (dextrin or a substance with the same effect) that has flavor retention properties as in the invention of
Prepare a formulation of Bx6-9. Then, a part of the thus obtained prepared liquid (maintained at low temperature) is concentrated to a concentration of about Bx 25 to 40 by vacuum concentration or membrane concentration, and the obtained concentrated liquid is mixed with the remainder of the unconcentrated prepared liquid, Obtain a mixed solution of Bx15-25 (undiluted solution for drying). Note that the operation of concentrating a portion of the unconcentrated extract and mixing the obtained concentrate with the remainder of the unconcentrated dissolved extract is usually called "cutback." Further, the ratio of the unconcentrated extract to the total weight of the concentrate and the remainder of the unconcentrated extract is called the "cutback ratio." The cutback ratio in preparing the liquid mixture (drying stock solution), that is, the ratio of the unconcentrated liquid to the drying stock solution, varies depending on the type of tea leaves, but is usually 40 to 80%. Cutback rate is 40
% or less, the ratio of the concentrated liquid to the unconcentrated mixture increases, and the flavor of the mixed liquid becomes considerably inferior to that of the undiluted liquid before concentration.On the other hand, if the cutback rate is 80% or more, the Bx of the mixed liquid increases. In order to set Bx to 15 or more, the Bx of the concentrate must be 40 or more, which substantially loses the meaning of concentration due to a decrease in concentration yield, which is also economically disadvantageous. In addition, the reason for adjusting the concentration of the mixed liquid to Bx 15 to 25 in the method of the present invention is that, in addition to maintaining the quality of the product, it is easy to process the powder after drying, and the bulk specific gravity is also sufficient. It's about getting something that satisfies you. Particularly when freeze-drying is used as a drying method, exceeding Bx25 may cause uneven drying, and the block obtained by drying is hard, so depending on the pulverization method, the generation of fine powder increases. On the other hand, if the concentration is lower than Bx15, not only bulky powder is obtained, but the significance of concentration is substantially lost, and it is also economically disadvantageous. According to the second aspect of the present invention, it is not only possible to economically concentrate and dry the extract, but also to obtain a powder that is satisfactory in terms of bulk specific gravity, etc., and according to this method. The resulting product has a good flavor comparable to that obtained with the first invention. In the following, the present invention will be explained in more detail with reference to Examples. Example 1 (A) 2 kg of sencha leaves were immersed in 14 kg of water at 30°C for 30 minutes, then immediately squeezed and rapidly cooled to 5°C to obtain 12 kg of squeezed juice of Bx4.1. 0.4 kg of powdered dextrin (with a DE of about 19) was added to 12 kg of this juice and dissolved, which was then freeze-dried to obtain 0.75 kg of powdered tea. (This is referred to as powdered tea A) (comparative example). (B) 2 kg of the same sencha leaves used in (A) were immersed in 14 kg of 70°C warm water for 20 minutes, then immediately squeezed and
It was rapidly cooled to ℃ to obtain 12 kg of squeezed liquid with Bx5.0. 0.49 kg of powdered doxtrin (with a DE of about 19) was added to 12 kg of this squeezed juice and dissolved, which was freeze-dried to obtain 0.9 kg of powdered tea (this is referred to as powdered tea B) (comparative example). (C) 1 kg of the same sencha leaves used in (A) at 30°C.
After soaking in 14kg of water for 20 minutes, the temperature was raised to 60℃.
Next, 1 kg of sencha leaves was added and soaked for 20 minutes.
This was immediately squeezed and rapidly cooled to 5°C to obtain 12 kg of squeezed juice of Bx5.2. 0.5 kg of powdered dextrin (with a DE of about 19) was added to 12 kg of this squeezed liquid, and the resulting solution was freeze-dried to obtain 0.9 kg of powdered tea (this will be referred to as powdered tea C) (implementation of the present invention) example). The three types of powdered tea obtained in (A) to (C) above are
It was dissolved in 150 ml of warm water (80°C) per 1.0 g, and a panel of 10 people was selected to compare the flavor and other characteristics and conduct a sensory test. The results are shown in Table 1, and it was found that the flavor of powdered tea C, compared to A and B, was almost the same as that of sencha obtained by the normal tea ceremony.

【table】

[Table] Example 2 (A) 50 kg of the juice preparation prepared by squeezing the juice according to the method of Example 1 (C) and dissolving powdered dextrin was used and concentrated under reduced pressure to obtain 21 kg of Bx21 concentrate. This concentrate was freeze-dried to obtain 38 kg of powdered tea (this was used as powdered tea D).
) (comparative example). (B) Using 50 kg of the same squeezed juice preparation as that used in A, 38 kg of it was concentrated under reduced pressure to obtain 9 kg of Bx37.5 concentrate. This concentrate and juice mixture 12Kg
Bx21 mixture (cutback rate
57%) was freeze-dried to obtain 3.8 kg of powdered tea. (This is referred to as powdered tea E) (Example of the second invention of the present invention). A comparative sensory test similar to the above was carried out by dissolving 1.0 g of the two powdered teas obtained above in 150ml of warm water (80°C), and also using the powdered tea C obtained in Example 1. I did this. The results are shown in Table-2. From Table 2, powdered tea E is almost equivalent to powdered tea C, and this shows that by partially concentrating the extract according to the present invention, it is possible to sufficiently compensate for the loss of aroma components caused by vacuum concentration. did.

【table】

[Table] Example 3 After soaking 3 kg of black tea leaves in 40 kg of 25°C water for 30 minutes,
The temperature was raised to ℃, and then 2 kg of black tea leaves were added and soaked for 20 minutes. This is immediately squeezed and cooled to 5℃.
36 kg of squeezed liquid of Bx5.3 was obtained. This juice was heated to 65°C using a plate heat exchanger and cooled to 5°C using a centrifuge, yielding 35 kg of a separated liquid of Bx5.3. Next, add powdered dextrin (DE: 19) to this separated liquid.
1.5 kg of Bx36.1 was dissolved, and 27.5 kg of this separated mixture was concentrated through a membrane to obtain 7 kg of Bx36.1 concentrate. Mix this concentrated liquid with the remaining 9 kg of the separated mixture to make 16 kg of Bx21 mixture (cutback rate 56%).
and then spray-dry this concoction to make powdered black tea.
Obtained 2.9Kg. Add 1.0g of the obtained powdered black tea to warm water (80%
When dissolved in 150 ml of ℃), a black tea with almost the same flavor as that obtained by the regular tea ceremony method was obtained. Effects of the Invention According to the first aspect of the present invention, by performing extraction of tea leaves in two stages under the above-mentioned conditions, it is possible to obtain instant tea having exactly the same flavor as regular tea. Furthermore, according to the second aspect of the present invention, by partially concentrating the tea leaf extract and cutting back the concentrated liquid, the tea leaf extract can be concentrated and dried economically. Similar to invention 1, instant tea with excellent flavor can be obtained.

Claims (1)

[Claims] 1. After performing the first extraction of tea leaves in low-temperature water and adding new tea leaves without separating the extracted tea leaves to reduce the ratio of water to tea leaves, the first A method for producing instant tea, which comprises performing a second extraction of tea leaves at a higher extraction temperature than the extraction temperature, followed by separating the tea leaves, adding a flavor-retaining substance to the resulting extract, and then drying. . 2. After the first extraction of the tea leaves is carried out in water at a low temperature, and after reducing the ratio of water to tea leaves by adding new tea leaves without separating the extracted tea leaves, the extraction temperature is higher than that of the first extraction. After performing a second extraction of the tea leaves and then separating the tea leaves and adding a flavor-retaining substance to the resulting extract, a portion of the extract is concentrated, and the resulting concentrate is added to the extract. A method for producing instant tea, characterized by mixing with the remainder and drying.