JP2007330190A - Tea beverage producing method, and tea beverage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tea beverage producing method preventing occurrence of secondary sediment even if using various kinds of tea leaves, and to provide tea beverage produced by the producing method. <P>SOLUTION: This tea beverage producing method comprises a process of extracting tea leaves with an alkaline solution, and a process of adjusting the concentration of the extracted solution obtained in the process of extracting tea leaves so as to obtain a prepared solution having strictinin concentration of 1.0 ppm - 10 ppm. The alkaline solution has preferably pH8.0-9.0, and is preferably obtained by adding sodium bicarbonate to water. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a tea beverage and a tea beverage.

  Tea is widely cultivated around the world, mainly in Asia, and is widely used around the world as three major non-alcoholic beverages along with coffee and cocoa. In general, tea beverages often have a health maintenance function typified by an antioxidant action and an anticancer action, and the demand for tea drinks has increased significantly in conjunction with the recent health boom. . As tea drinks, many unfermented teas and weakly fermented teas filled in cans or PET bottle containers are sold.

In such tea beverages, floc-like precipitates, so-called “secondary orientation” may be generated during storage.
This secondary orientation is presumed to occur when strictinin in the tea beverage is decomposed and bound to protein or the like.

Then, the method of depositing and filtering the substance which causes a secondary orientation is proposed (for example, refer patent document 1).
In this method, ascorbic acid is added to an extract obtained by extracting green tea with warm water to adjust to an acidic region, which is rapidly cooled, and then the extract is filtered by centrifugation or the like. Then, the extract is filtered and clarified, and then the pH of the extract is adjusted to a neutral range.
In such a method, the formation of orientation is promoted by adjusting the extract obtained by hot water extraction of green tea to an acidic region and quenching it. And since this ori is filtered and removed, the causative agent of ori is reduced in the manufactured tea beverage, and a tea beverage that does not generate ori is produced over time.

However, in the method described in Patent Document 1, secondary orientation may occur depending on the type of tea leaf used.
In order to solve this problem, a method has been proposed in which a tea leaf having a low strictinin concentration is selected in advance as a raw tea leaf to produce a tea beverage (see, for example, Patent Document 2).
According to the method described in Patent Document 2, by measuring the strictinin concentration of the raw tea leaves and selecting in advance a tea leaf having a low strictinin concentration as the raw tea, it is possible to produce a tea beverage that is unlikely to generate secondary orientation. It is said that.

Japanese Patent Publication No.7-97965 JP 2003-235451 A

However, the technique described in Patent Document 2 has room for improvement in the following points.
In the technique described in Patent Document 2, when producing a tea beverage, it is necessary to strictly select a raw tea leaf in advance and use a tea leaf having a low strictinin concentration. Therefore, the types of tea leaves that can be used are limited.

  An object of the present invention is to provide a method for producing a tea beverage capable of preventing the occurrence of secondary orientation even when various types of tea leaves are used, and a tea beverage produced by this production method. is there.

  According to the present invention, the step of extracting tea leaves with an alkaline solution and the concentration of the extract obtained in the step of extracting tea leaves are adjusted, and a liquid preparation having a strictinin concentration of 1.0 ppm or more and 10 ppm or less is prepared. And a step of obtaining a tea beverage.

According to the present invention, the strictinin concentration in the extract can be lowered by extracting tea leaves with an alkaline solution. Then, by appropriately adjusting the extraction time, the extraction temperature, etc., a preparation liquid having a strictinin concentration of 1.0 ppm or more and 10 ppm or less is obtained. Thereby, it is possible to obtain a tea beverage that is unlikely to generate secondary orientation.
In the present invention, the concentration of strictinin in the extract can be lowered by extracting tea leaves with an alkaline solution, and a prepared solution having a strictinin concentration of 1.0 ppm to 10 ppm can be obtained. Therefore, the tea leaves are not limited to specific raw tea leaves having a low strictinin concentration, and a wider variety of tea leaves can be used as raw tea leaves.
Furthermore, conventionally, when producing a tea beverage, the use of tea leaves having a low strictinin concentration reduces the strictinin concentration in the tea beverage, so the selection of tea leaves had to be performed strictly.
On the other hand, in the present invention, the concentration of strictinin in the extract can be lowered by extracting the tea leaves with an alkaline solution or the like, so that it is not necessary to select the tea leaves in advance. Thereby, the manufacturing process of a tea drink can be simplified.
In addition, in this invention, since the strictinin density | concentration in a preparation liquid is 1.0 ppm or more, it can prevent producing a tea drink too thin in terms of palatability.

At this time, the alkaline solution in the step of extracting tea leaves is preferably pH 8.0 or more and 9.0 or less.
By setting the pH of the alkaline solution to not less than 8.0 and not more than 9.0, the strictinin concentration in the extract can be reliably reduced.
Moreover, it is preferable that pH of the extract obtained at the said process which extracts a tea leaf is 6.5 or more and 7.5 or less.
The pH of the produced tea beverage is preferably 6.2 or higher. Therefore, generally, when adjusting the concentration of the preparation liquid, the pH is also adjusted. By adjusting the pH of the extract to 6.5 or more and 7.5 or less, significant pH adjustment is not necessary when adjusting the pH of the preparation.
Further, by setting the pH of the extract to 6.5 or more, the ratio of the amount of the main amino acid (the sum of theanine and glutamic acid) to the amount of tannin can be increased as compared with the case where the pH of the extract is set to less than 6.5. it can. Thereby, it can be said that astringency can be suppressed and umami can be extracted predominantly.

Furthermore, in the step of extracting tea leaves, it is preferable to obtain the alkaline solution by adding at least one of baking soda and potassium carbonate to water.
The pH of the alkaline solution can be stably maintained by adding at least one of sodium bicarbonate and potassium carbonate to water.

Furthermore, in the step of obtaining the preparation liquid, it is preferable to adjust the concentration of the extract and to add potassium carbonate to the extract.
By adding potassium carbonate to the extract, the pH of the preparation can be stably maintained. Moreover, the salty taste derived from Na atom can be reduced by adding potassium carbonate to the extract as compared with the case of adding sodium bicarbonate or the like.
Depending on the amount of catechins in the tea beverage, it is easy to feel a salty taste, so it is particularly useful to add potassium carbonate to the extract.

The number of K atoms / number of Na atoms, which is the ratio of the content of potassium atoms and sodium atoms in the preparation liquid, is preferably 0.5 or more and 1.5 or less.
By making the K atom number / Na atom number in the preparation liquid 0.5 or more and 1.5 or less, the salty taste of the tea beverage derived from Na atoms can be reliably reduced.

Further, at this time, in the step of obtaining the preparation liquid, it is preferable to obtain a preparation liquid having a catechin concentration of 200 ppm or more and 800 ppm or less.
When tea leaves are extracted with an alkaline aqueous solution as in the present invention, the amount of catechins in the extract and the preparation may be reduced. Therefore, it is preferable to adjust the extraction time and the extraction temperature as appropriate so that the catechin concentration in the preparation liquid is 200 ppm or more and 800 ppm or less (the catechin concentration in the extract is 600 ppm or more and 4000 ppm or less). Thereby, it is possible to obtain a tea beverage that contains a sufficient amount of catechins and is less likely to generate secondary orientation.

  Moreover, according to this invention, the tea drink manufactured by the manufacturing method of one of the tea drinks mentioned above can also be provided.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where various types of tea leaves are used, the production | generation method of the tea beverage which can prevent generation | occurrence | production of a secondary orientation, and the tea beverage manufactured by this manufacturing method are provided.

  The present invention includes a step of extracting tea leaves with an alkaline solution, and a step of adjusting the concentration of the extract obtained in the step of extracting tea leaves to obtain a liquid preparation having a strictinin concentration of 1.0 ppm to 10 ppm. A method for producing a tea beverage comprising:

  Here, strictinin is a substance represented by the following chemical formula (1-O-galloyl-4,6-O- (S) -hexahydroxydiphenoyl-β-D-glucose), which is tannin extracted from tea. Is a type of ellagitannins ("Casuariin, Stachyurin and Strictinin, new Ellagitannins from Casuarina Stricta and Stachyurus Praecox", Chem. Pharm. Bull. 30 (2) 766-769 (1982)).

In the present invention, the tea beverage refers to non-fermented tea and weakly fermented tea. The tea beverage of the present invention includes semi-fermented tea such as oolong tea, fermented tea such as black tea, and post-fermented tea such as puer tea. Is not included.
Examples of the tea beverage of the present invention include green tea, and more specifically, sencha, kettle roasted tea, kabuse tea, gyokuro, tencha, matcha, bancha, roasted tea, steamed ball green tea, kettle roasted ball green tea and the like. can give.

Below, it demonstrates in detail regarding the manufacturing method of the tea drink of this invention.
The tea beverage is (A) a step of extracting tea leaves with an alkaline solution (B) a step of filtering the extract (C) a concentration and pH of the extract, and a strictinin concentration of 1.0 ppm or more and 10 ppm or less Step (D) of obtaining a liquid It is manufactured through a step of heat sterilizing the prepared liquid.

(A) Step of extracting tea leaves with an alkaline solution In this step, an open type extraction device called a kneader is used to introduce tea leaves as raw materials into an alkaline solution (alkaline aqueous solution) for extraction.
The alkaline aqueous solution preferably has a pH of 8.0 or more and 9.0 or less, and this alkaline aqueous solution is obtained by adding sodium bicarbonate to water. In addition to sodium bicarbonate, potassium carbonate may be added, or potassium carbonate may be added instead of sodium bicarbonate.
The alkaline aqueous solution preferably has a pH of 8.5 or higher, and more preferably has a pH of 8.9 or lower. By setting the pH of the alkaline aqueous solution to 8.5 or more, the strictinin concentration in the extract can be reliably suppressed. Moreover, there exists an effect of suppressing the excessive quality change of catechin by making pH of alkaline aqueous solution 8.9 or less.
Moreover, as water which is a solvent of alkaline aqueous solution, hard water, soft water, ion-exchange water, natural water, etc. can be used.
Furthermore, the alkaline aqueous solution is preferably about 30 times the weight of the tea leaves.

Moreover, it is preferable that the temperature of alkaline aqueous solution is 50-70 degreeC, Most preferably, it is 55 degreeC or more and 65 degrees C or less.
In the extraction, it is preferable to stir the alkaline aqueous solution. Furthermore, the pressure at the time of extraction may be normal pressure, but may be extracted by pressurization.

If tea leaves are extracted with an alkaline aqueous solution as in the present invention, the amount of catechins in the extract may be reduced. Therefore, it is preferable to adjust the extraction time, the extraction temperature, etc. as appropriate so that the concentration of catechins in the extract is 600 ppm or more and 4000 ppm or less. By setting the concentration of catechins in the extract to 600 ppm or more and 4000 ppm or less, a tea beverage having excellent flavor and color can be produced.
Here, catechins refer to epicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, catechin, gallocatechin, methylated catechin and optical isomers thereof.

Moreover, it is preferable that pH of an extract is 6.5 or more and 7.5 or less. Especially, it is preferable that it is pH 6.8 or more, and it is further preferable that it is pH 7.2 or less.
Compared with the case where the pH of the extract is 6.5 or more, preferably 6.8 or more, and the pH of the extract is less than 6.5, the ratio of the main amino acid (the sum of theanine and glutamic acid) to the amount of tannin Can be increased. Thereby, it can be said that astringency can be suppressed and umami can be extracted predominantly.
Here, the main amino acid (sum of theanine and glutamic acid) amount / tannin amount is preferably 0.054 or more.
The amount of major amino acids and the amount of tannin are values measured in units of mg / 100 ml.
Moreover, it is preferable that the pH of the manufactured tea drink will be 6.2 or more. Therefore, generally, when adjusting the concentration of the preparation liquid, the pH is also adjusted. By adjusting the pH of the extract to 6.5 or more and 7.5 or less, significant pH adjustment is not necessary when adjusting the pH of the preparation.
Furthermore, excessive alteration of catechin can be suppressed by setting the pH of the extract to 7.5 or less.

(B) The process of filtering an extract In this process, while removing the tea leaves etc. which were mixed in the extract, the substance which causes a primary orientation is removed. For example, after the extract is centrifuged, membrane filtration or the like is performed.

(C) The process of adjusting the density | concentration and pH of an extract, and obtaining the liquid preparation whose strictinin density | concentration is 1.0 ppm or more and 10 ppm or less In this process, first, an extract is diluted 3-6 times with water. Thereafter, ascorbic acid, sodium ascorbate, saccharides, dextrin, fragrance, emulsifier, stabilizer and the like are added to the diluted extract.

Furthermore, it is preferable to add at least one of baking soda or potassium carbonate to the diluted extract to adjust the pH of the preparation to 6.5 or more and 8.0 or less.
Here, it is preferable that the number of K atoms / the number of Na atoms, which is the ratio of the content of potassium atoms and sodium atoms in the preparation liquid, is 0.5 or more and 1.5 or less. Of these, the number of K atoms / number of Na atoms is preferably 0.6 or more. By setting the number of K atoms / the number of Na atoms to 0.5 or more, preferably 0.6 or more, the salty taste of the tea beverage derived from Na atoms can be reliably reduced.
Further, the number of K atoms / number of Na atoms is preferably 1.2 or less. By setting the number of K atoms / Na atoms to 1.5 or less, preferably 1.2 or less, there is an effect of suppressing excessive bitterness derived from K atoms.

The strictinin concentration in such a preparation liquid is 1.0 ppm or more and 10 ppm or less. Especially, it is preferable that the strictinine density | concentration in a preparation liquid is 4 ppm or more, Furthermore, it is preferable that it is 8 ppm or less. By setting the strictinin concentration in the preparation liquid to 4 ppm or more, there is an effect of preventing the production of a tea beverage having a thickness less than that generally felt to be preferable. Moreover, there exists an effect of delaying the generation | occurrence | production time of a secondary orientation more by making the strictinin density | concentration in a preparation liquid into 8 ppm or less.
Furthermore, in this step, it is preferable that the concentration of catechins in the preparation liquid is 200 ppm or more and 800 ppm or less. By setting the catechin concentration in the preparation liquid to 200 ppm or more and 800 ppm or less, a tea beverage having excellent flavor and color tone can be obtained.

(D) Process of heat-sterilizing preparation liquid In this process, preparation liquid is heat-sterilized. Here, the heat sterilization may be performed after filling the preparation liquid into a container or the like, or may be performed before filling.
When using a container that is vulnerable to heating, such as a PET bottle, the container may be preliminarily sterilized at a high temperature for a short time, and then cooled to a certain temperature and filled in the container.

Here, strictinin in the preparation liquid is decomposed into ellagic acid by heat sterilization. This ellagic acid is considered to be a causative substance of secondary soil. In the present embodiment, since the strictinin concentration in the preparation liquid is controlled to 1.0 ppm or more and 10 ppm or less, it is possible to provide a tea beverage that is less likely to cause secondary orientation.
Although the preparation liquid heat-sterilized in this way becomes a tea drink, it is preferable that pH of this tea drink is 6.2 or more. More preferably, it is pH 6.4 or more and 7.3 or less. Thus, by making pH of a tea drink 6.2 or more, generation | occurrence | production of the acidity derived from the fall of pH at the time of long-term storage can be suppressed. Moreover, there exists an effect of making the natural tea fragrance stand by making pH of a tea drink 7.3 or less.

Next, the effect of this embodiment is demonstrated.
By extracting tea leaves with an alkaline solution, the strictinin concentration in the extract can be lowered. In addition, by appropriately adjusting the extraction time, the extraction temperature, and the like, it is possible to obtain a preparation liquid having a strictinin concentration of 1.0 ppm or more and 10 ppm or less. Thereby, it is possible to obtain a tea beverage that is unlikely to generate secondary orientation.
In addition, by performing extraction of tea leaves with an alkaline solution or the like, the strictinin concentration in the extract can be lowered, and a strictinin concentration of 1.0 ppm or more and 10 ppm or less can be obtained. Not only specific raw tea leaves having a low concentration, but also a wider variety of tea leaves can be used as raw tea leaves.

Conventionally, when producing a tea beverage, the use of tea leaves having a low strictinin concentration reduces the strictinin concentration in the tea beverage, so the selection of tea leaves had to be performed strictly.
On the other hand, in this embodiment, since the concentration of strictinin in the extract can be reduced by extracting tea leaves with an alkaline solution, it is not necessary to select tea leaves in advance. Thereby, the manufacturing process of a tea drink can be simplified.
In addition, in this invention, since the strictinin density | concentration in a preparation liquid is 1.0 ppm or more, it can prevent producing a tea drink too thin in terms of palatability.

Furthermore, by setting the pH of the alkaline solution to 8.0 or more, the strictinin concentration in the extract can be reliably reduced.
Moreover, the excessive quality change of catechin can be suppressed by making pH of an alkaline solution 9.0 or less.
Furthermore, in the step of extracting tea leaves, an alkaline solution is obtained by adding at least one of baking soda and potassium carbonate to water. The pH of the alkaline solution can be stably maintained by adding at least one of sodium bicarbonate and potassium carbonate to water.

In the step of obtaining the preparation liquid, it is preferable to add potassium carbonate to the extract.
By adding potassium carbonate to the extract, the pH of the extract can be stably maintained. Moreover, the salty taste derived from Na atom can be reduced by adding potassium carbonate to the extract as compared with the case of adding sodium bicarbonate or the like.
Depending on the amount of catechins in the tea beverage, it is easy to feel salty taste, so it is useful to add potassium carbonate to the extract.

Furthermore, the salty taste of tea drinks derived from Na atoms is reliably reduced by setting the number of K atoms / Na atoms, which is the ratio of the number of potassium atoms and the number of sodium atoms in the preparation, to 0.5 or more. Can be made.
Moreover, there exists an effect of suppressing the excessive bitterness derived from K atom by making K atom number / Na atom number or less into 1.5.

Next, examples of the present invention will be described.
Example 1
A tea beverage was produced by the same method as in the previous embodiment.
In the process of extracting tea leaves, sodium bicarbonate was added to water to prepare an alkaline solution having a pH of 8.8. This alkaline solution was brought to 55 ° C., and tea leaves (trade name: No. 2 tea / No. 4 tea blend from Shizuoka) were added to the alkaline solution and stirred. The extraction time was 7 minutes. The pH of the obtained extract was 7.1.
Thereafter, the extract was diluted 5.0 times and sodium ascorbate or the like was added. Furthermore, potassium carbonate and sodium bicarbonate were added to prepare a preparation solution having a pH of 7.2.
The concentration of strictinin in the preparation liquid was 6.6 ppm, and the concentration of catechins was 267 ppm.
Further, the number of K atoms / number of Na atoms in the preparation liquid was 0.61.

  The strictinin concentration, catechin concentration, K atom number / Na atom number were measured by the following methods.

  Concentration of strictinin: High performance liquid chromatography (LC-2010C, manufactured by Shimadzu Corporation) was used. A column temperature of 40 ° C., a flow rate of 1.0 ml / min, a mobile phase prepared as mobile phase A, water: acetonitrile: phosphoric acid prepared at 400: 10: 1, and mobile phase B as methanol: mobile phase A were prepared. What was prepared 1: 2 was prepared. The analysis was started at a ratio of mobile phase A: mobile phase B of 80%: 20%, and the ratio of mobile phase B was gradually increased, and the process was terminated when mobile phase A: mobile phase B was 20%: 80%. .

  Catechin concentration: High performance liquid chromatography (CLASS-VP manufactured by Shimadzu Corporation) was used. Column temperature 40 ° C., flow rate 1.0 ml / min, mobile phase prepared as mobile phase A 0.1% acetonitrile, 0.5% N, N dimethylformamide, 0.1% phosphoric acid solution, mobile phase B As a sample, 100% acetonitrile was prepared. The analysis was started at a rate of 99%: 1% for mobile phase A: mobile phase B, and the rate of mobile phase B was gradually increased, and the analysis was terminated when mobile phase A: mobile phase B was 0%: 100%. .

  Number of K atoms / number of Na atoms: A sequential type high frequency plasma emission analyzer (ICPS-7000, manufactured by Shimadzu Corporation) was used. Samples were diluted appropriately with 1% nitric acid solution. The number of atoms of K and Na was calculated from the obtained concentrations of K and Na and the respective atomic weights.

(Example 2)
A tea beverage was produced by the same method as in the previous embodiment.
In the process of extracting tea leaves, sodium bicarbonate was added to water to prepare an alkaline solution having a pH of 8.5. The alkaline solution was brought to 80 ° C., and tea leaves (trade name: Chinese-style roasted green tea) were added to the alkaline solution and stirred. The extraction time was 7 minutes. The pH of the obtained extract was 6.7.
Thereafter, the extract was diluted 5.7 times and sodium ascorbate or the like was added. Furthermore, potassium carbonate and sodium bicarbonate were added to prepare a preparation solution having a pH of 7.7.
The concentration of strictinin in the preparation liquid was 2.8 ppm, and the concentration of catechins was 339 ppm.
Further, the K atom number / Na atom number in the preparation liquid was 0.88.

(Example 3)
A tea beverage was produced by the same method as in the previous embodiment.
In the process of extracting tea leaves, sodium bicarbonate was added to water to prepare an alkaline solution having a pH of 8.8. The alkaline solution was brought to 90 ° C., and tea leaves (trade name: Kyushu No. 2 Tea No. 3 Tea Blend) were added to the alkaline solution and stirred. The extraction time was 5 minutes. The pH of the obtained extract was 7.0.
Thereafter, the extract was diluted 3.6 times and sodium ascorbate or the like was added. Further, potassium carbonate and sodium bicarbonate were added to prepare a pH 7.5 preparation.
The strictinin concentration in the preparation liquid was 9.0 ppm, and the catechin concentration was 752 ppm.
Further, the K atom number / Na atom number in the preparation liquid was 1.02.

Example 4
A tea beverage was produced by the same method as in the previous embodiment.
In the step of extracting tea leaves, sodium bicarbonate was added to water to prepare an alkaline solution having a pH of 8.7. The alkaline solution was adjusted to 60 ° C., and tea leaves (trade name: Kawane 2nd tea, Shizuoka 2nd tea / 4th tea blend) were added to the alkaline solution and stirred. The extraction time was 6 minutes. The pH of the obtained extract was 6.9.
Thereafter, the extract was diluted 5.1 times and sodium ascorbate or the like was added. Furthermore, potassium carbonate and sodium bicarbonate were added to prepare a preparation solution having a pH of 7.2.
The concentration of strictinin in the preparation liquid was 8.4 ppm, and the concentration of catechins was 386 ppm.
Further, the K atom number / Na atom number in the preparation liquid was 0.71.
Further, (glutamic acid amount + theanine amount) / tannin amount in the preparation liquid was calculated to be 0.0555.
Here, the amount of glutamic acid, the amount of theanine, and the amount of tannin in the preparation liquid were calculated as mg / 100 ml. The amount of glutamic acid + theanine was measured as follows.
Main amino acid amount (glutamic acid amount + theanine amount): A fully automatic amino acid analyzer (JLC-500 / V manufactured by JEOL Ltd.) was used. The sum of the amount of theanine detected and the amount of glutamic acid (unit: mg / 100 ml) was defined as the amount of main amino acids.

(Example 5)
A tea beverage was produced by the same method as in the previous embodiment.
In the process of extracting tea leaves, sodium bicarbonate was added to water to prepare an alkaline solution having a pH of 8.9. This alkaline solution was brought to 60 ° C., and tea leaves (trade name: Kawane 2nd tea, Shizuoka 2nd tea / 4th tea blend) were added to this alkaline solution and stirred. The extraction time was 6 minutes. The pH of the obtained extract was 7.0.
Thereafter, the extract was diluted 5.1 times and sodium ascorbate or the like was added. Furthermore, potassium carbonate and sodium bicarbonate were added to prepare a preparation solution having a pH of 7.2.
The strictinin concentration in the preparation liquid was 6.6 ppm, and the catechin concentration was 228 ppm.
Further, the number of K atoms / number of Na atoms in the preparation liquid was 0.61.
In addition, (glutamic acid amount + theanine amount) / tannin amount in the preparation liquid was calculated to be 0.0586.
Here, the amount of glutamic acid, the amount of theanine, and the amount of tannin in the preparation solution were calculated as mg / 100 ml and measured by the same method as in Example 4.

(Comparative Example 1)
In the process of extracting tea leaves, pure water was used, and this pH was 6.5. This pure water was brought to 55 ° C., and tea leaves (trade name: Shizuoka No. 2 tea No. 4 tea blend) were added to the hot pure water and stirred. The extraction time was 7 minutes. The pH of the obtained extract was 6.1.
Thereafter, the extract was diluted 4.7 times and sodium ascorbate or the like was added. Furthermore, potassium carbonate and sodium bicarbonate were added to prepare a preparation solution having a pH of 7.0.
The concentration of strictinin in the preparation liquid was 10.9 ppm, and the concentration of catechins was 461 ppm.
Further, the K atom number / Na atom number in the preparation liquid was 0.77.

(Comparative Example 2)
In the process of extracting tea leaves, sodium bicarbonate was added to water to prepare an alkaline solution having a pH of 8.6. The alkaline solution was brought to 55 ° C., and tea leaves (trade name: Kawane 2nd tea) were added to the alkaline solution and stirred. The extraction time was 7 minutes. The pH of the obtained extract was 7.1.
Thereafter, the extract was diluted 4.9 times and sodium ascorbate or the like was added. Furthermore, potassium carbonate and sodium bicarbonate were added to prepare a preparation solution having a pH of 7.2.
The concentration of strictinin in the preparation liquid was 12.7 ppm, and the concentration of catechins was 386 ppm.
Furthermore, the number of K atoms / number of Na atoms in the preparation liquid was 0.69.

(Comparative Example 3)
In the process of extracting tea leaves, sodium bicarbonate was added to water to prepare an alkaline solution having a pH of 8.8. The alkaline solution was brought to 55 ° C., and tea leaves (trade name: No. 4 tea from Shizuoka) were added to the alkaline solution and stirred. The extraction time was 6 minutes. The pH of the obtained extract was 7.0.
Thereafter, the extract was diluted 5.7 times and sodium ascorbate or the like was added. Furthermore, potassium carbonate and sodium bicarbonate were added to prepare a pH 6.9 preparation.
The strictinin concentration in the preparation liquid was 0.9 ppm, and the catechin concentration was 212 ppm.
Further, the number of K atoms / number of Na atoms in the preparation liquid was 0.81.

(Comparative Example 4)
In the process of extracting tea leaves, pure water was used, and this pH was 6.5. The pure water was adjusted to 60 ° C., and tea leaves (trade name: Kawane 2nd tea, Shizuoka 2nd tea / 4th tea blend) were added to the warm pure water and stirred. The extraction time was 6 minutes. The pH of the obtained extract was 6.1.
Thereafter, the extract was diluted 5.2 times and sodium ascorbate or the like was added. Furthermore, potassium carbonate and sodium bicarbonate were added to prepare a pH 6.4 preparation.
The strictinin concentration in the preparation liquid was 11.1 ppm, and the catechin concentration was 447 ppm.
Further, the K atom number / Na atom number in the preparation liquid was 0.57.
Further, (glutamic acid amount + theanine amount) / tannin amount in the preparation liquid was calculated to be 0.0531.
Here, the amount of glutamic acid, the amount of theanine, and the amount of tannin in the preparation solution were calculated as mg / 100 ml and measured by the same method as in Example 4.

(Evaluation of Examples and Comparative Examples)
It left still in the storage managed at 60 degreeC, and the presence or absence of the generation | occurrence | production of an orientation after 2 weeks was evaluated.

In Examples 1 to 5 in which the strictinin concentration in the preparation liquid was 1.0 ppm or more and 10 ppm or less, secondary orientation was not generated. On the other hand, in Comparative Examples 1, 2, and 4, secondary orientation occurred.
Moreover, although the secondary orientation did not generate | occur | produce in the comparative example 3 whose strictinin density | concentration in a preparation liquid is 0.9 ppm, it became a tea drink too thin in terms of palatability.
Further, when Examples 4 and 5 were compared with Comparative Example 4, in Examples 4 and 5, the amount of (glutamic acid amount + theanine amount) / tannin amount in the preparation liquid was 0.054 or more, In Comparative Example 4, the (glutamic acid amount + theanine amount) / tannin amount in the preparation liquid was less than 0.054. Compared to Comparative Example 4, it can be seen that Examples 4 and 5 can suppress astringency and extract umami preferentially.

Claims (8)

Extracting tea leaves with an alkaline solution;
Adjusting the concentration of the extract obtained in the step of extracting tea leaves, and obtaining a preparation liquid having a strictinin concentration of 1.0 ppm or more and 10 ppm or less. In the manufacturing method of the tea drink of Claim 1,
The said alkaline solution of the said process of extracting a tea leaf is a manufacturing method of the tea drink whose pH is 8.0 or more and 9.0 or less. In the manufacturing method of the tea drink of Claim 1 or 2,
A method for producing a tea beverage, wherein the pH of the extract obtained in the step of extracting tea leaves is 6.5 or more and 7.5 or less. In the manufacturing method of the tea drink in any one of Claims 1 thru | or 3,
In the step of extracting tea leaves, a method for producing a tea beverage, wherein the alkaline solution is obtained by adding at least one of baking soda and potassium carbonate to water. In the manufacturing method of the tea drink in any one of Claims 1 thru | or 4,
In the step of obtaining a preparation liquid, the concentration of the extract is adjusted, and a method for producing a tea beverage in which potassium carbonate is added to the extract. In the manufacturing method of the tea drink in any one of Claims 1 thru | or 5,
In the step of obtaining the preparation liquid, a method for producing a tea beverage for obtaining a preparation liquid having a K atom number / Na atom number which is a ratio of the content of potassium atom and sodium atom is 0.5 or more and 1.5 or less. In the manufacturing method of the tea drink in any one of Claims 1 thru | or 6,
In the said process of obtaining a liquid mixture, the manufacturing method of the tea drink which obtains the liquid mixture whose catechin density | concentration is 200 ppm or more and 800 ppm or less.   A tea beverage produced by the method for producing a tea beverage according to any one of claims 1 to 7.