JP2005278519A - Post-heating fermented tea beverage and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain post-heating fermented tea beverage containing much gallic acid with strong antioxidative force activity, and having less bitterness in spite of containing a lot of catechins and strong relish and body taste. <P>SOLUTION: The post-heating fermented tea beverage is obtained by performing slurry fermentation with Aspergillus and collecting tea leaf suspension when the slurry fermentation is finished. The post-heating fermented tea beverage has, compared with other tea beverage, a smaller extracted volume of catechins with a gallate group per unit tea leaf of dried tea leaves, a larger extracted volume of gallic acid per unit tea leaf and higher water-soluble solid content per unit tea leaf. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a post-fermented tea beverage having a high bitter taste and a strong umami taste and a rich taste despite a high amount of gallic acid having a strong antioxidant activity and a high amount of catechins, and a method for producing the same. Is.

  Tea is roughly classified into non-fermented tea (green tea), semi-fermented tea (Oolong tea), fully fermented tea (black tea) and post-fermented tea (black tea) due to the difference in its production method. That is, unfermented tea is obtained by steaming or heat-treating fresh tea leaves and killing them, then twisting and drying them, and the enzyme group of the fresh tea leaves themselves is lost. On the other hand, semi-fermented tea and completely fermented tea are those that have not been killed, but have been fermented and fermented by the action of the enzyme group of the fresh tea leaves themselves, and then the enzyme group is inactivated by heating and dried. Yes, it can be divided into semi-fermented tea and completely fermented tea depending on the degree of fermentation.

  Further, post-fermented tea is usually obtained by planting mold using unfermented tea that has been subjected to blue-killing treatment and depositing it to cause gonococcal fermentation. The characteristics of post-fermented tea are that semi-fermented tea and fully fermented tea convert polyphenols from fresh tea leaves into theaflavins by the action of polyphenol oxidase, which is an oxidase of fresh tea leaves. In addition, catechins having a gallate group in tea leaves are decomposed to produce gallic acid having a strong antioxidant effect, and water-soluble solids derived from tea leaves are also produced by the plant tissue-degrading enzyme of koji mold, resulting in umami and It is said that the richness is increasing.

  However, the content of tannin and caffeine in the hot water extract of Pu'er tea, a kind of post-fermented tea, compared with green tea and black tea, the amount of caffeine in Pu'er tea is not much different from that of green tea and black tea. However, tannin is said to have a considerably low content (see Table 1 below, cited from Non-Patent Document 1).

  Moreover, in the said nonpatent literature 1, although the content in each tea leaf is measured about the catechin which is the main components in tea leaf tannin, in the puer tea where the catechin which the gallate group couple | bonded is post-fermented tea. The amount of catechins in the hot water extract is about several percent of that in the green tea extract. This is because catechins are oxidized during the fermentation process. The content is thought to have been reduced.

  Therefore, various tea leaves were extracted again with boiling water, and their water-soluble solid content (Bx value), tannin content using the tartaric acid / iron colorimetric method, which is the official method for tannin measurement, and high-performance liquid chromatography (HPLC method) The gallic acid and catechin content values were measured. It was found that the post-fermented tea Pu'er tea and 3-year black tea were not high in Bx value, tannin content value, gallic acid and catechin content values compared to other tea leaves (see Tables 2 and 3). ).

  In view of these circumstances and the recent increase in public interest in the physiological functionality of tea catechins, the content of catechins bound to gallate groups with strong bitter taste has been increased for the purpose of improving the flavor of beverages. Considering a method for producing a new tea leaf that contains as little gallic acid and other catechins as possible, and can extract a large amount of water-soluble solids that decompose the tea leaf plant tissue and cause umami and richness. It was decided to.

  About the method of processing a tea leaf by an enzyme or fermentation, until now, for example in patent document 1, patent document 2, patent document 3, patent document 4, patent document 5, and patent document 6, the purpose which mainly prevents the cream-down of black tea Although techniques relating to efficient tannase production by Aspergillus niger or Oryzae, which are koji molds that produce tannase frequently used in Japan, have been disclosed, the effect is obtained by directly acting on tea leaves. It is not intended to be.

  Further, Patent Document 7 proposes a method for producing catechins having stronger antioxidant power by converting crude catechins obtained from tea leaves into gallic acid and free catechins using tannase. It is not intended to obtain an effect by directly acting on tea leaves, but refers to a method in which tea leaf plant tissue is further decomposed to extract a large amount of water-soluble solids that are the source of umami and richness. is not.

  On the other hand, in Patent Document 8, after adding tannase to a tea leaf hot water leachate and reacting it, an alkali is added to the reaction solution to have a fresh flavor and enhanced antioxidant power. Although a method for obtaining a drink has been proposed, it is not intended to obtain an effect by directly acting on tea leaves, but further, a water-soluble solid that is the source of umami and kokumi when tea leaf plant tissue is further decomposed It does not mention a method that can extract a lot of minutes.

  Furthermore, Patent Document 9 proposes a method for producing a tea beverage with less turbidity by combining chlorogenic acid esterase and tannase produced by Aspergillus in the tea extract. It is not intended to obtain an effect by acting, and does not refer to a method in which tea leaf plant tissue is further decomposed to extract a large amount of water-soluble solids that are the source of umami and richness.

  Further, in Patent Document 10, it was found that by extracting tea raw materials in the presence of protease and tannase, protein bound to tannin in tea leaves was effectively decomposed, and the release of amino acids was promoted. In particular, a method for obtaining a tea beverage with enhanced umami and kokumi has been proposed, but efficient degradation of tea leaf plant tissue is not possible only in the presence of protease and tannase, and cellulose, hemicellulose, The combination of degradation of polysaccharides such as pectin is an essential requirement, and the enhancement of umami and richness associated with the degradation is not negligible. In addition, more water-soluble solids, tannins, and catechins can be obtained by simply decomposing polysaccharides such as proteins, cellulose, hemicellulose, pectin, etc. using koji molds, compared to simply combining proteases, cellulases, hemicellulases and pectinases. Extraction of tea materials in the presence of protease and tannase is the same as the extraction of water from tea leaves and the production of other organic acids, flavors, etc. associated with Aspergillus oryzae fermentation. It is not possible to equate tea fermentation with koji mold.

  Patent Document 11 proposes to take out the active ingredients of umami and sweetness of tea leaves, tea trees and tea tree roots directly by using fermentative bacteria and useful microorganisms. No specific bacterial species or specific fermentation action has been identified for many fermentative bacteria and useful microorganisms, and as introduced in post-fermented tea, it is fermentative and useful in Pu'er tea and Japanese black tea. It is a well-known fact that tea leaves have been fermented by the gonococcus, a microorganism, since ancient times. In Southeast Asia, tea that is fermented in the form of pickles by lactic acid bacteria and other microorganisms is also known. It cannot be said that the present invention involves a simple method and proposal.

Monthly Food Chemicals August 1990 "Effects of Chinese Black Tea (Post-fermented Tea) on Lipid Metabolism" Sano Mitsaki and Tomita Isao Japanese Patent Publication No.56-8484 JP-A-4-360684 Japanese Examined Patent Publication No. 6-32609 Japanese Patent Publication No. 7-79687 JP-A-8-80196 JP 2003-250588 A Japanese Patent Publication No. 5-79070 Japanese Patent Laid-Open No. 10-313784 JP 11-308965 A JP 2003-1444049 A Japanese Patent Laid-Open No. 2003-274861

  The present invention has been made in view of the above circumstances, contains a large amount of gallic acid with strong antioxidant activity, and has a little bitter taste despite being rich in catechins. The main object is to provide a strong post-fermented tea beverage and a method for producing the same.

  In order to achieve the above object, the present invention performs slurry fermentation with Aspergillus oryzae, collects tea leaf suspension at the end of the slurry fermentation, and extracts catechins having gallate groups per unit tea leaf in dried tea leaves The amount of gallic acid per unit tea leaf is higher than that of other tea beverages, and the water-soluble solid content per unit tea leaf is higher than that of other tea beverages. A post-fermented tea beverage is provided. The post-fermented tea beverage of the present invention has a smaller amount of catechins having a gallate group than other tea beverages, a larger amount of gallic acid than other tea beverages, and other water-soluble solids. Therefore, it is possible to obtain a tea beverage having little bitter and astringent taste and strong umami and richness in spite of containing a large amount of catechins.

  Further, the present invention is slurry fermentation in which fermentation of post-fermented tea is performed by pulverizing raw tea leaves and suspending the crushed raw tea leaves in water, and this slurry fermentation has an enzyme of Aspergillus oryzae. The present invention provides a method for producing a post-fermented tea beverage, wherein the koji mold is performed in a temperature range where it does not grow and proliferate. By performing fermentation under such conditions, post-fermentation with a strong bitter taste and a strong taste with little bitter taste despite a high amount of gallic acid with strong antioxidant activity and a high content of catechins You can get tea.

Moreover, in the said invention, it is preferable that fermentation of the said post-fermented tea is performed using the koji mold which has tannase activity and plant tissue degradation activity, and especially the said koji mold is isolated from black tea which is post-fermented tea. It is preferred that This is because the post-fermented tea of the present invention can be produced more effectively by using such a koji mold.
Furthermore, in the present invention, the raw tea leaves are preferably green tea, semi-fermented tea, or completely fermented tea.

  According to the present invention, it is possible to obtain a post-fermented tea beverage that contains a large amount of gallic acid having a strong antioxidant activity and a low bitter taste despite a high content of catechins and a strong umami and richness. There is an effect that can be.

  The present inventor decomposes tea leaf plant tissue to extract water-soluble solids and tannins that are notable for physiological functionality from tea leaves as much as possible to the maximum extent possible. Decomposes catechins to which strong gallate groups are bound, and at the same time produces and contains a large amount of gallic acid with strong antioxidant activity, and contains a large amount of catechins, unlike Pu'er tea and 3-year black tea. However, a new post-fermented tea beverage with little bitterness and strong taste and richness and a method for producing the same were studied. As a result, in the conventional method for producing post-fermented tea by koji mold fermentation, it is said that fermentation is performed in a hot and humid atmosphere where koji mold cannot grow after the middle of the koji mold fermentation process. First of all, the water-soluble solids that are the source of umami and richness from tea leaves, gallic acid, tannin, and catechins are low in order to spread the koji molds throughout the tea leaves in the early stages of fermentation. Fermentation must be carried out at a fermentation temperature that takes into account the growth and proliferation of Aspergillus oryzae planted in tea leaves. Because of the growth and proliferation of Aspergillus oryzae, it is water-soluble as the source of umami and rich taste from tea leaves. Because it consumes solids, gallic acid, tannins, and catechins, water-soluble solids, gallic acid, tannins, and catechins obtained from Pu'er tea and 3-year black tea are reduced. It was heading.

  Conventionally, in literatures and the like, it has been explained that the catechins of Pu'er tea are less catechins are oxidatively polymerized in the fermentation process and the content is reduced. In the early stage of fermentation, when the koji mold is spread and spread uniformly on the tea leaves, water-soluble solids, gallic acid, tannin, and catechins that are the source of umami and rich taste from tea leaves are consumed as a source of koji mold. Turned out to be.

  Based on these facts, as a result of further earnest and examination, the slurry fermentation method using raw tea leaves as raw materials that have not been subjected to blueprinting, that is, the enzyme activity in the raw tea leaves, has been studied by the present inventors. In addition, tea leaves that have been killed, that is, tea leaves that do not retain enzyme activity in raw tea leaves are used as raw materials, and then koji molds are planted in wet tea leaves that have been heat-sterilized in advance, and solid culture is performed, which has strong tannase activity and plant tissue degradation activity If a koji mold is obtained and added to a slurry fermentation solution, and slurry fermentation is performed while stirring in a temperature zone where the koji mold does not grow and proliferate and the enzymes in the koji mold can sufficiently act, koji mold derived from tea leaves can be obtained. Since fermented products are not consumed as a nutrient source for koji mold, the tea leaf plant tissue is decomposed, and the water-soluble solids and physiological functions that are the source of umami and kokumi to the maximum extent possible from tea leaves Produces tannins that attract attention, decomposes catechins bound to gallate groups with a strong bitter taste, and at the same time produces and contains a large amount of gallic acid with strong antioxidant activity, Pu'er tea and 3-year black Unlike tea, it has been found that a new post-fermented tea having a strong bitterness and richness can be produced despite the fact that it contains a large amount of catechins, and the present invention has been completed.

  Of course, there is no problem in carrying out slurry fermentation with Aspergillus oryzae using fresh tea leaves that are usually used in slurry fermentation, but it is within the technical scope of the present invention. It is preferable to use tea leaves in which the enzyme group has been deactivated.

  Hereinafter, the post-fermented tea beverage of the present invention and the production method thereof will be described in detail. Here, the manufacturing method of a post-fermented tea drink will be described first, and then the post-fermented tea drink will be described.

A. Method for producing post-fermented tea beverage The method for producing post-fermented tea beverage of the present invention is slurry fermentation in which fermentation of post-fermented tea is performed by pulverizing raw tea leaves and suspending the crushed raw tea leaves in water, In addition, this slurry fermentation is characterized in that it is carried out in a temperature range in which the koji mold enzyme has activity but the koji mold does not grow and proliferate. In the present invention, the fermentation of post-fermented tea is carried out in a temperature range in which the koji mold enzyme has activity but koji mold does not grow and proliferate. Because it does not consume water-soluble solids, gallic acid, tannin, and catechins that are the source of umami and richness, it contains a lot of gallic acid with strong antioxidant activity and a lot of catechins. In spite of this, it is possible to obtain a post-fermented tea beverage with little bitterness and a strong umami and richness.
The raw tea leaves used in such a method for producing post-fermented tea of the present invention are not particularly limited, and may be any of green tea, semi-fermented tea, and completely fermented tea, and usually are used for killing or What was heated and the enzyme group which tea leaves itself have deactivated is used.

Moreover, although fermentation of the said raw material tea leaf is performed using a koji mold, it is not specifically limited as a koji mold to be used, but koji mold having tannase activity and plant tissue degrading activity is preferably used. By using such a koji mold, the above-mentioned action and effect, that is, containing a large amount of gallic acid having a strong antioxidant activity and having a lot of catechins, there is little bitterness and taste, This is because a strong post-fermented tea beverage can be obtained.
As such an aspergillus, what was isolated from black tea which is post-fermented tea can be used, for example. Specifically, although not particularly limited, Aspergillus genus and Penicillium genus mold found in the post-fermentation process of black tea, preferably Aspergillus niger having the tannase activity and plant tissue degrading activity, oryzae, glaucus or the like can be used.

In the present invention, fermentation using such koji molds is performed by pulverizing raw tea leaves and suspending the crushed raw tea leaves in water, that is, by a slurry fermentation method. This is because the temperature control is easy and the production of gallic acid and the production of water-soluble solids are efficiently performed by slurry fermentation.
The raw tea leaves are pulverized by a method used in a usual slurry fermentation method, and specifically, a food cutter and a mixer, a hammer mill, an ultramizer and the like are appropriately used as necessary. The size of the crushed raw tea leaves is not particularly limited, but may be about 1 mm or less.

  The raw tea leaves thus pulverized are added to water and koji molds solid-cultured from the tea leaves as raw materials and subjected to slurry fermentation. As described above, koji molds that are solid-cultured using tea leaves as a raw material are usually used as described above, but koji molds that are liquid-cultured using tea leaves as a raw material may be used. Further, the water used in the present invention is not particularly limited, but it is preferable to use deionized water or distilled water. Thus, deionized water or distilled water is preferable when calcium ions, iron ions, etc. are dissolved in the water, resulting in binding with tannins in the tea leaf extract, resulting in insoluble matter, and color. This is to prevent the change from occurring.

  The weight ratio of the raw materials when slurry fermentation is performed is not particularly limited and may vary greatly depending on the type of raw tea leaves used and the required palatability. However, generally, the ground tea leaf pulverized product is put into water within a range of 5.0 wt% to 30 wt% to perform fermentation and extraction treatment. In this case, the koji mold that has been solid-cultured using the added tea leaves as a raw material varies depending on the type and the like, but is usually in the range of 0.5 wt% to 10.0 wt%, particularly 1.0 wt%. % To 5.0% by weight is added.

  As described above, the temperature condition for performing the slurry fermentation is a temperature range in which the koji mold enzyme has activity but the koji mold does not grow and proliferate. Here, the temperature zone where the koji mold does not grow and proliferate is usually a temperature of 45 ° C. or more, but the specific fermentation temperature is a mold detection medium that preliminarily indicates the presence or absence of koji mold growth during slurry fermentation. It is preferable to confirm and determine in advance, in particular, preliminarily confirm beforehand the presence or absence of gonococcal growth during slurry fermentation in the mold detection medium, the production of gallic acid by slurry fermentation of tea leaves and water-soluble solids It is desirable to determine the minute production.

Such a temperature range varies greatly depending on the type of koji mold, the type of tea leaves, etc., but is usually in the range of 45 ° C. to 70 ° C., particularly in the range of 48 ° C. to 63 ° C. It is preferably within the range of ° C.
In addition, the fermentation time varies greatly depending on the type of koji mold, the type of raw tea leaves, etc., but usually the time period during which the production of gallic acid and the production of water-soluble solids by slurry fermentation of tea leaves reaches its maximum. Although it is a target, a time zone lower than that or a time zone higher than that may be adopted depending on the target flavor and the content composition of catechins. The purpose of the present invention is to achieve the maximum production of gallic acid and water-soluble solids by slurry fermentation of tea leaves, so that it is usually within the range of 8 hours to 30 days, particularly 1 day to It is preferably performed within a range of 10 days.

After the slurry fermentation process is completed, in order to deactivate the enzyme activity of Aspergillus, usually a heat treatment at about 95 ° C. for about 30 minutes is performed, followed by a solid-liquid separation process to obtain a post-fermented tea extract.
In the solid-liquid separation step in the present invention, a solid-liquid separation method used in a normal slurry fermentation method is used. Specifically, it is performed by a method such as a centrifugal separation method or a filtration separation method.

  The post-fermented tea extract thus obtained is diluted with water so that the Bx value has a predetermined concentration, and the necessary additives, specifically, a pH adjuster, further flavoring, For the purpose of coloring and antioxidant, pH adjusters such as sodium bicarbonate and potassium bicarbonate, flavors such as tea flavor, colorants such as chlorophyll, antioxidants such as ascorbic acid or its salts and rutin, sucrose fatty acid An antibacterial emulsifier such as an ester is added to sterilize by heating to obtain a post-fermented tea beverage.

B. Post-fermented tea beverage Next, the post-fermented tea beverage of the present invention will be described. Tea The post-fermented beverage of the present invention is a water-soluble solid content per unit tea leaf in the tea leaf obtained by recovering and drying the tea leaf suspension at the end of the slurry fermentation described in “A. Method for producing post-fermented tea beverage” above. The amount of gallic acid extracted is larger than that of other tea beverages, and catechins having a gallate group are less than those of other tea beverages.
The post-fermented tea beverage of the present invention can be obtained, for example, by the production method described in the column “A. Method for producing post-fermented tea beverage” above.

  In the present invention, the suspension of tea leaves at the end of slurry fermentation is collected in this way, the water-soluble solid content per unit tea leaf in the dried tea leaves, the amount of gallic acid extracted is greater than other tea beverages, The catechins having a gallate group are characterized by being less than other tea beverages, and this is determined by the following method.

That is, slurry fermentation similar to that described in the column of “A. Method for producing post-fermented tea beverage” is performed, and the tea leaf suspension after the completion of slurry fermentation is heated to sterilize the koji mold, The tea leaves recovered after inactivation and dried are used. On the other hand, in the case of other tea leaves, except that the koji mold is not added, slurry fermentation is performed by the same method, and the tea leaf suspension after completion of the slurry fermentation is recovered and dried tea leaves are used.
Further, the obtained tea leaves are extracted with hot water, and a supernatant liquid is obtained by centrifugation or filtration separation and used for analysis.
In addition, the water-soluble solid content in the obtained supernatant liquid is a Bx value by a refractometer, and the amount of gallic acid and the amount of catechin are measured by high performance liquid chromatography (HPLC). The total amount of tannin is measured by the tartaric acid / iron colorimetric method.

  Here, the amount of water-soluble solids per unit tea leaf, the amount of catechins having gallic acid and gallate groups extracted is the amount of hot water added when extracting tea leaves with hot water and the amount of water-soluble solids in the supernatant. The value obtained by multiplying the amount of gallic acid or the amount of catechins having a gallate group by the amount of tea leaves used.

Incidentally, since the Bx value as a water-soluble solid content is expressed by weight / weight%, it was calculated as water-soluble solid content g / supernatant g for convenience.
In the present invention, the extraction amount of water-soluble solids and gallic acid per unit tea leaf determined by the above-described method is larger than that of other tea beverages. The amount of extractable soluble solids and gallic acid is determined, meaning that this is less than the post-fermented tea beverage of the present invention.

In the present invention, the amount of water-soluble solids per unit tea leaf and the amount of gallic acid extracted is not particularly limited as long as it is larger than other tea beverages.For example, when green tea leaves are fermented with koji molds, The extraction amount of water-soluble solids per unit tea leaf is within the range of 0.4 g / tea leaf g to 0.9 g / tea leaf g, and in particular within the range of 0.4 g / tea leaf g to 0.7 g / tea leaf g, The amount of gallic acid extracted per unit tea leaf is preferably within the range of 13 mg / tea leaf g to 50 mg / tea leaf g, and more preferably within the range of 15 mg / tea leaf g to 45 mg / tea leaf g. In addition, when the oolong tea leaves are also fermented, the extraction amount of water-soluble solids per unit tea leaves is usually within the range of 0.4 g / tea leaves to 0.9 g / tea leaves g, especially 0.4 g / tea leaves g. Within the range of ˜0.7 g / tea leaf g, and the amount of gallic acid extracted per unit tea leaf is within the range of 13 mg / tea leaf g˜50 mg / tea leaf g, particularly within the range of 15 mg / tea leaf g—35 mg / tea leaf g. Preferably there is.
Next, when black tea leaves are also fermented, the extraction amount of water-soluble solids per unit tea leaves is usually within the range of 0.4 g / tea leaves to 0.9 g / tea leaves g, especially 0.4 g / tea leaves. g to 0.7 g / tea leaf g, and the amount of gallic acid extracted per unit tea leaf is within the range of 13 mg / tea leaf g to 50 mg / tea leaf g, especially within the range of 15 mg / tea leaf g to 35 mg / tea leaf g. It is preferable that

In the present invention, it is preferable that the amount of catechins having a gallate group per unit tea leaf is smaller than that of other tea leaves. This is because the post-fermented tea beverage can be made with a small bitter astringency but a large amount of total catechin.
In this case as well, there is no particular limitation as long as the amount of catechins having a gallate group per unit tea leaf is smaller than that of other tea beverages. For example, when green tea leaves are fermented with koji molds, The extraction amount of catechins having a gallate group is preferably in the range of 0.0 mg / tea leaf g to 6.0 mg / tea leaf g, particularly preferably in the range of 0.0 mg / tea leaf g to 3.5 mg / tea leaf g. . In addition, when oolong tea leaves are also fermented, the extraction amount of catechins having a gallate group per unit tea leaf is usually within the range of 0.0 mg / tea leaf g to 5.0 mg / tea leaf g, especially 0.0 mg / It is preferable to be within the range of tea leaf g to 3.0 mg / tea leaf g. Furthermore, when the tea leaves are also fermented, the amount of catechins having a gallate group per unit tea leaf is usually within the range of 0.0 mg / tea leaf g to 5.0 mg / tea leaf g, especially 0.0 mg / It is preferable to be within the range of tea leaf g to 1.0 mg / tea leaf g.

  The present invention is not limited to the above embodiment. The above embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the claims of the present invention, and has the same operational effects or equivalents thereof. Is included in the technical scope of the present invention.

Hereinafter, the present invention will be specifically described with reference to examples.
(Example 1)
The green tea leaves were crushed into powder, and 100 parts by weight of water was added to and mixed with 100 parts by weight of the powdered green tea leaves, followed by heat sterilization at 120 ° C. for 20 minutes. After cooling to 25 ° C., Aspergillus niger, which is a koji mold having tannase activity and plant tissue degrading activity, was inoculated and subjected to solid culture at 25 ° C. for 7 days to obtain koji mold using tea leaves as a raw material. Next, 90 parts by weight of water and 7 parts by weight of green tea leaves pulverized into powder and 3 parts by weight of koji mold obtained by solid culture were added and mixed, and the slurry was stirred at 55 ° C. for 2 days with stirring. Fermentation was performed. Further, heat treatment was performed at 95 ° C. for 30 minutes to sterilize the koji mold, deactivate tannase activity and plant tissue degrading activity, and freeze-dry the slurry fermentation suspension to obtain dried tea leaves. The obtained dried tea leaves were extracted with hot water, and the amount of water-soluble solids per unit tea leaf, the amount of gallic acid, and catechins having a gallate group were analyzed. The amount of water-soluble solids was 0.58 g / tea leaf g, The amount of gallic acid was 25.3 mg / g tea leaf, and the catechins having a gallate group were 0.0 mg / g tea leaf. Next, based on the analysis result of catechins, a tea drink containing 100 mg / 100 ml of catechins was prototyped and the flavor was evaluated. As a result, there was no bitter and astringent taste, and there was umami and richness.

(Comparative Example 1)
93 parts by weight of water and 7 parts by weight of green tea leaves pulverized into powder were added and mixed, followed by stirring at 55 ° C. for 2 days. Further, a heat treatment at 95 ° C. for 30 minutes was performed, and the stirred suspension was lyophilized to obtain dry tea leaves. The obtained dried tea leaves were extracted with hot water, and the amount of water-soluble solids per unit tea leaf, the amount of gallic acid, and catechins having a gallate group were analyzed. The amount of water-soluble solids was 0.31 g / tea leaf g, The amount of gallic acid was 1.8 mg / g tea leaf, and catechins having a gallate group were 17 mg / g tea leaf. Next, based on the analysis result of catechins, a tea drink containing 100 mg / 100 ml of catechins was prototyped and its flavor was evaluated. As a result, the bitter and astringent taste was strong, and the taste and taste were low.

(Example 2)
The oolong tea leaves were crushed into powder, and 100 parts by weight of water was added to and mixed with 100 parts by weight of the powdered oolong tea leaves, followed by heat sterilization at 120 ° C. for 20 minutes. After cooling to 25 ° C., Aspergillus niger, which is a koji mold having tannase activity and plant tissue degrading activity, was inoculated and subjected to solid culture at 25 ° C. for 7 days to obtain koji mold using tea leaves as a raw material. Next, 90 parts by weight of water and 7 parts by weight of oolong tea leaves pulverized into powder and 3 parts by weight of koji mold obtained by solid culture were added and mixed. Fermentation was performed. Further, heat treatment was performed at 95 ° C. for 30 minutes to sterilize the koji mold, deactivate tannase activity and plant tissue degrading activity, and freeze-dry the slurry fermentation suspension to obtain dried tea leaves. The obtained dried tea leaves were extracted with hot water and analyzed for water-soluble solid content, gallic acid content, and catechins having a gallate group per unit tea leaf, water-soluble solid content was 0.43 g / tea leaf g, The amount of gallic acid was 20.0 mg / g tea leaf, and catechins having a gallate group were 1.8 mg / g tea leaf. Next, based on the analysis result of catechins, a tea drink containing 100 mg / 100 ml of catechins was prototyped and the flavor was evaluated. As a result, there was no bitter and astringent taste, and there was umami and richness.

(Comparative Example 2)
93 parts by weight of water and 7 parts by weight of oolong tea leaves pulverized into powder were added and mixed, followed by stirring at 55 ° C. for 2 days. Further, a heat treatment at 95 ° C. for 30 minutes was performed, and the stirred suspension was lyophilized to obtain dry tea leaves. The obtained dried tea leaves were extracted with hot water and analyzed for water-soluble solid content, gallic acid content and catechins having a gallate group per unit tea leaf. The water-soluble solid content was 0.33 g / tea leaf g, gallic acid. The acid amount was 6.8 mg / tea leaf g, and catechins having a gallate group were 16 mg / tea leaf g. Next, based on the analysis result of catechins, a tea drink containing 100 mg / 100 ml of catechins was prototyped and its flavor was evaluated. As a result, the bitter and astringent taste was strong, and the taste and taste were low.

(Example 3)
The tea leaves were crushed into powder, and 100 parts by weight of water was added to and mixed with 100 parts by weight of the powdered tea leaves, followed by heat sterilization at 120 ° C. for 20 minutes. After cooling to 25 ° C., Aspergillus niger, which is a koji mold having tannase activity and plant tissue degrading activity, was inoculated and subjected to solid culture at 25 ° C. for 7 days to obtain koji mold using tea leaves as a raw material. Next, 90 parts by weight of water and 7 parts by weight of tea leaves pulverized into powder and 3 parts by weight of koji mold obtained by solid culture were added and mixed, and the slurry was stirred at 55 ° C. for 2 days with stirring. Fermentation was performed. Further, heat treatment was performed at 95 ° C. for 30 minutes to sterilize the koji mold, deactivate tannase activity and plant tissue degrading activity, and freeze-dry the slurry fermentation suspension to obtain dried tea leaves. The obtained dried tea leaves were extracted with hot water, and the amount of water-soluble solids per unit tea leaf, the amount of gallic acid, and catechins having a gallate group were analyzed. The amount of water-soluble solids was 0.47 g / tea leaf g, The amount of gallic acid was 21 mg / g tea leaf, and catechins having a gallate group were 0.0 mg / g tea leaf. Next, based on the analysis result of catechins, a tea drink containing 100 mg / 100 ml of catechins was prototyped, and the flavor was evaluated. As a result, there was no astringency and bitterness, and there was umami and richness. .

(Comparative Example 3)
93 parts by weight of water and 7 parts by weight of crushed black tea leaves were added and mixed, and stirred at 55 ° C. for 2 days. Further, a heat treatment at 95 ° C. for 30 minutes was performed, and the stirred suspension was lyophilized to obtain dry tea leaves. The obtained dried tea leaves were extracted with hot water and analyzed for water-soluble solid content, gallic acid content, and catechins having a gallate group per unit tea leaf, water-soluble solid content was 0.36 g / tea leaf g, The amount of gallic acid was 11 mg / g tea leaf, and catechins having a gallate group were 6 mg / g tea leaf. Next, on the basis of the analysis result of catechins, a tea beverage containing 100 mg / 100 ml of catechins was prototyped and the flavor was evaluated. As a result, the astringent taste was strong, the bitterness and astringency were strong, and the taste and taste were low there were.

Claims (5)

  Perform slurry fermentation with Aspergillus oryzae, collect the tea leaf suspension at the end of the slurry fermentation, and extract less catechins having gallate groups per unit tea leaf in the dried tea leaves than other tea beverages, A post-fermented tea beverage characterized in that the amount of gallic acid extracted per tea leaf is greater than that of other tea beverages, and the water-soluble solid content per unit tea leaf is greater than that of other tea beverages.   The fermentation of post-fermented tea is slurry fermentation in which the raw tea leaves are crushed and the crushed raw tea leaves are suspended in water, and this slurry fermentation is a temperature at which the koji mold enzyme has activity but koji mold does not grow and proliferate A method for producing a post-fermented tea beverage, characterized in that the method is performed in a belt.   The method for producing a post-fermented tea beverage according to claim 2, wherein the fermentation of the post-fermented tea is performed using koji mold having tannase activity and plant tissue degrading activity.   The method for producing a post-fermented tea beverage according to claim 3, wherein the koji mold is isolated from black tea which is post-fermented tea. The method for producing a post-fermented tea beverage according to any one of claims 2 to 4, wherein the raw tea leaves are green tea, semi-fermented tea, or completely fermented tea.