JPH10313784A - Manufacture of tea improved in quality - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide tea having a fresh flavor immediately after hot water exudation even at the time of being preserved for the long period of time and improved in antioxidation power by adding tannase to hot water exuding liquid, making it react, then adding alkali to the reactive liquid and adjusting it to specified pH. SOLUTION: After adding the tannase to the hot water exuding liquid of the tea and making it react, by adding the alkali (example; sodium bicarbonate or sodium hydroxide), adjusting the pH to 4.5-6.0 and then powdering it preferably, the tea is obtained. Also, as the tannase, an optional enzyme is used as long as it has activity for decomposing tannin. To put it concretely, the tannase obtained by cultivating tannase production bacteria belonging to Aspergillus, Penicillium, Rhizopus and Mucor, etc., for instance is suitably used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for producing tea using tannase, and in particular, has a fresh flavor immediately after hot water leaching of tea and has an enhanced antioxidant power even after long-term storage. It relates to a method for producing tea.

[0002]

2. Description of the Related Art The applicant of the present invention first added tannase to a hot water leaching solution of tea and reacted it. Even if the temperature was lowered, no turbid matter was precipitated, and the astringency was reduced and the flavor was good. A patent application has been filed for a method for producing tea that is suitable for drinking as cold tea (Japanese Patent Application Laid-Open Nos. 49-110899 and 49-110900). However, as a result of further study of these inventions in detail, as a result of adding and reacting tannase to a hot water leachate of tea, the astringency is reduced and the taste becomes good. It was found that the fresh aroma immediately after leaching was impaired and the taste was slightly sour, slightly different from the fresh taste immediately after leaching. On the other hand, the hot water leaching solution of tea is rich in catechins. These catechins have an antioxidant effect on edible oils and fats, an antibacterial effect on food poisoning bacteria, a blood cholesterol concentration increase suppressing effect, an angiotensin converting enzyme inhibiting effect and a blood pressure increase suppressing effect, an α-amylase inhibitory effect and a blood glucose increase suppressing effect, Since it has excellent physiological activities such as anti-mutation in microorganisms and anti-tumor effect in mice or rats, if its excellent drug efficacy can be enhanced, it will make a great contribution to the food and pharmaceutical industries.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a tea having a fresh flavor immediately after hot tea leaching and having enhanced antioxidant power even when stored for a long period of time.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, after causing tannase to act on a hot water leaching solution of tea, an alkali was added to the reaction solution. When adjusting the pH to 4.5 to 6.0, it is possible to obtain tea with fresh aroma and taste immediately after hot water leaching of tea and storage of antioxidant power even after long-term storage. The present invention has been completed based on these findings. That is, the present invention is characterized in that after adding tannase to hot water leaching solution of tea and reacting, the pH is adjusted to 4.5 to 6.0 by adding alkali to the reaction solution. The present invention is a method for producing tea, and the present invention is a method of adding tannase to a hot water leaching solution of tea to cause a reaction, and then adding an alkali to the reaction solution to adjust the pH.
Is adjusted to 4.5-6.0 and then powdered.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present invention, hot water is first poured into tea, and then boiled for several minutes if necessary, then leached with hot water, and then filtered to prepare a hot water brewed tea.

Examples of the tea used in this case include fermented tea such as black tea, non-fermented tea such as green tea, and semi-fermented tea such as oolong tea.

Next, the hot water leachate or its concentrated solution (for example, a concentrate obtained by concentrating about 10 times) is cooled to 30 to 45 ° C., and tannase is added thereto for reaction.

As the tannase used in the present invention, any enzyme having an activity of decomposing tannin can be used. Specifically, for example, a tannase obtained by culturing a tannase-producing bacterium belonging to the genus Aspergillus, Penicillium, Rhizopus, Mucor or the like is preferably used. Note that a commercially available tannase (enzyme agent) such as tannase manufactured by Kikkoman Corporation may be used.

The amount of tannase to be added is determined according to the titer of the tannase enzyme preparation and the total solid content contained in the hot water leachate of tea.
Units or more, preferably 0.2 units or more (1 unit is 30 ° C
1 ester bond contained in tannic acid in water
(Indicating the amount of enzyme that hydrolyzes micromolar).

When tannase is added, it is preferable to adjust the temperature of the hot water leachate (or its concentrate) which is affected by tannase to 30 to 60 ° C. And
The tannase is reacted under such conditions for 10 to 60 minutes.

As described above, when tannase is allowed to act on the hot water leachate of tea, the pH of the leachate gradually decreases, and the hot water leachate of tea that has finally undergone the reaction of tannase is 0.5 to 0.5 times less than that at the start. It was found that 1.0 was also reduced.

In the present invention, alkali is added to the hot water leaching solution of tea treated with tannase to adjust the pH to 4.5 to 4.5.
Adjust to 6.0. In the present invention, this pH adjustment is very important, and the purpose of the present invention (that is, the fragrance immediately after the hot water leaching of tea and the fragrance) is very important even if the pH is too low or higher than 6.0. To obtain a tea with a taste). That is, when it is less than 4.5, the taste has a slightly sour taste, and when it exceeds 6.0, the tea has a taste slightly different from the taste immediately after leaching with hot water.

The alkali used herein includes sodium hydrogen carbonate, sodium hydroxide and the like.

[0014]

As described above, the tea exudate obtained by adjusting the pH may be used as it is (or further heat-sterilized) as a tea beverage, but if necessary, it may be powdered to give instant powdered tea. May be used. The powdered tea obtained here has a feature of being excellent in solubility in cold water. Further, according to the present invention, even when stored for a long period of time, a tea having a fresh flavor immediately after infused with hot water and having enhanced antioxidant power as compared with the conventional method can be easily obtained.

[0015]

【Example】

Example 1 300 g of hot water at about 90 ° C. was added to 6 g of ordinary black tea and leached for about 5 minutes, followed by filtration with a cloth to obtain about 280 ml of “tea hot water leaching solution”. This hot water leachate (about pH
5.0) After cooling 100 ml as it is to 35 ° C.,
50 units of Kikkoman's tannase were added and mixed, kept at that temperature for 30 minutes to allow tannase to act,
"Tannase-treated solution (pH 4.4)" was obtained. Then, a small amount of sodium hydrogen carbonate was added to
H was returned to 5.0 to obtain a tea beverage of the present invention. Comparative Example For comparison, the tea beverage of Comparative Example was prepared in the same manner as above except that sodium bicarbonate was not added to the “tannase-treated solution (pH 4.4)” (that is, pH was not adjusted). Obtained. Next, regarding the tea beverage of the present invention or the comparative example, the “hot tea leachate” before tannase treatment
In comparison with, a sensory test was conducted for the fragrance and taste. The tea beverages used for the sensory test were all cooled immediately after preparation, put in a test tube with a capacity of 50 ml, sealed and stored in a refrigerator (5 ° C) for 1 month, and heated to 80 ° C. Used. As a result, when the tea beverage of the comparative example is stored for one month, the fragrance is slightly deteriorated, and the taste also has a slightly sour taste. found. On the other hand, it was found that the tea beverage of the present invention had aroma and taste comparable to those of the control tea beverage immediately after the tea was leached with hot water even after storage for one month.

Example 2 A tea beverage was prepared in the same manner as in the method for producing a tea beverage of the present invention in Example 1, and freeze-dried to obtain an instant powdered tea of the present invention. For comparison, a tea beverage was prepared in the same manner as in the method for producing the tea beverage of the comparative example, and was freeze-dried to obtain an instant powdered tea of the comparative example.

Application Example Test Example of Confirming the Antioxidant Effect of Ethyl Linoleate on Ethyl Linoleate by Adding Ethanol-soluble Fraction of Powdered Tea of the Present Invention To 10 g of instant powdered tea of the present invention obtained in Example 2, 20 ml of pure ethanol was mixed. After stirring at room temperature for 5 hours, the mixture was filtered through a filter paper to extract an ethanol-soluble fraction of the powdered tea. Similarly, an ethanol-soluble fraction of the powdered tea of Comparative Example was extracted. On the other hand, 30 ml of ethyl linoleate is divided into three sections of 10 ml each, and the first section is 0.5 m of pure ethanol.
0.5 ml of the ethanol-soluble fraction of the instant powdered tea of the comparative example in the second section, and 0.5 ml of the ethanol-soluble fraction of the powdered tea of the present invention in the third section. added. Each was maintained at 50 ° C., and the antioxidant power was evaluated by observing an increase in the peroxide value (POV) over time. The peroxide value was determined according to the method described in Lipid Peroxide Experimental Method by Naoshi Kaneda et al. (Ishiyaku Shuppan, published on October 20, 1983, page 59. The results are shown in FIG.

From FIG. 1, in the first section (no addition), the peroxide value rapidly increased with time, but the second section (the ethanol-soluble fraction of powdered tea of the comparative example was added) and the It can be seen that the oxidation of ethyl linoleate was suppressed in all three categories (to which the ethanol-soluble fraction of the powdered tea of the present invention was added). And it turns out that the effect is remarkable especially in the third section to which the ethanol-soluble fraction of the powdered tea of the present invention is added.
From these results, it can be seen that according to the present invention, a tea beverage or powdered tea having enhanced antioxidant power as compared with the conventional method can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing the antioxidant effect on ethyl linoleate by adding an ethanol-soluble fraction of the powdered tea of the present invention.

Claims (2)

[Claims] After adding tannase to a hot water leaching solution of tea and reacting it, an alkali is added to the reaction solution to adjust the pH to 4.
A method for producing tea of improved quality, characterized in that the tea is adjusted to 5 to 6.0. 2. After adding tannase to a hot water leaching solution of tea to cause a reaction, an alkali is added to the reaction solution to adjust the pH to 4.
A method for producing tea of improved quality, characterized in that the tea is adjusted to 5-6.0 and then powdered.