JP2013252128A - Method for improving quality of low-grade tea and green tea with improved quality - Google Patents

Abstract

[Problem] To provide a comprehensive method for improving the quality of green tea low-grade tea (typically, Nibancha, Sanbancha, and Akiyubancha).
[Solution] The tea leaves with enzyme activity remaining together with sodium ascorbate, magnesium chloride and yeast extract were prepared, and a low-grade tea leaf was brought into contact therewith to generate a sufficient scent component from the tea leaves. Later, enzyme deactivation treatment is performed. β-primeverosidase is allowed to act to develop a fragrance, and the combined use of sodium ascorbate, magnesium chloride and yeast extract produces a refreshing yellow-green color, reducing bitterness and astringency and increasing umami. can do. Therefore, the quality of low-grade tea can be improved with a high overall balance. The scent includes a green scent that makes green tea feel and a floral scent that makes tea feel. In addition, the extraction efficiency is improved, making it suitable for cold tea and packaged beverages.
[Selection] Figure 1

Description

  The present invention relates to a method for comprehensively improving the quality of low-quality green tea (typically Nibancha, Sanbancha, and Akiyubancha) and green tea with improved quality.

  Scientific elucidation about the benefits of tea has progressed, inhibiting the intake of fat into the body and suppressing the increase in neutral fat, which is effective for adult diseases, promoting fat burning and preventing obesity, antioxidant Has been shown to suppress the generation of active oxygen and prevent cancer, and suppress viral growth and prevent colds. For this reason, tea is a typical food that you want to take actively.

As for the preference for green tea, a questionnaire survey was conducted. As shown in Non-Patent Document 1, “Like” was concentrated on savory green tea and fragrant green tea, and the next was clean green tea. New tea and kabuse tea, which are picked and processed in the spring, match the palatability of this green tea, have a good aroma and umami, and have little bitter taste, so it can be enjoyed deliciously, but it is a limited amount when viewed from the whole. Is also expensive. On the other hand, the second, third and autumn / winter teas, which are picked and processed from early summer to autumn, lack the aroma and umami and have a strong bitter taste, so the price is low but consumer demand is low.
As a result, the price of crude tea has been sluggish and a vicious circle of farmers' decline in production is falling. However, since the content of catechins having health functions is large, if the above-mentioned quality can be improved in a cost-appropriate manner, consumers can purchase cheap and delicious tea and expect an increase in demand.

Thus, conventionally, there has been no report that has improved the above-mentioned quality in a well-balanced manner, and only reports that have been improved in a fragmentary manner.
For example, Patent Document 1 discloses that egg white, ascorbate, and magnesium salt are added to blanched tea leaves to obtain a green tea powder with excellent astringency and low astringency.
Patent Document 2 discloses that powdered tea is dipped in ascorbic acid or sodium ascorbate to suppress the fading of instant green tea and the generation of altered odors.
Patent Document 3 discloses a tea beverage containing a yeast extract as a taste improver.
Patent Document 4 discloses a method for producing a fermented tea beverage that is crushed by adding water to fresh tea leaves, has little bitter taste, no cream down, and has excellent aroma and sweetness.
Patent Document 5 discloses a method for producing a green tea extract having an excellent flavor by reacting dried green tea leaves with an enzyme solution.
Patent Document 6 discloses a method for producing a green tea beverage raw material liquid that is mixed with frozen fresh tea leaves and water, has excellent aroma from crushed juice and has reduced bitterness.
In Patent Document 7, a fermented tea leaf having a rich floral scent is produced by inoculating fungi such as the genus Aspergillus on fermented tea leaves obtained by spraying a slurry of fresh tea leaves on green tea or rough tea. A method is disclosed.
Patent Document 8 discloses a method for producing a tea extract that gives a fruity feeling by causing an enzyme having β-glycosidase activity to act on tea components extracted from raw tea leaves.

Japanese Patent Laid-Open No. 3-80045 JP 2006-254819 A JP 2005-278475 A Republished patent WO2009 / 119112 Republished patent WO2008 / 001848 JP 2007-110990 A JP 2012-80812 A JP 2011-250736 A

Kyoto Prefectural Tea Chamber, 2005 8th Uji Tea Health Forum “Green Tea and Health” Lecture Collection, pp. 3-20

Therefore, in order to solve the above-mentioned problems, the present invention has an object to provide a comprehensive quality improvement method for low-quality green tea (typically, second, third, and autumn / winter tea). And
Another object of the present invention is to provide green tea with improved quality using low-grade tea as a raw material.

Since glucoside, which is a scent substrate, also remains in the tea leaves treated with blue-killing, it can be expected that scent will develop if the enzyme in the raw tea leaves is acted on, but the fresh tea leaves are not deactivated for a short time. It turns brown.
As a result of earnest research, the present inventor has improved both of the above-mentioned fragrance and light blue color by using specific components in combination, and can further reduce bitterness and astringency, thereby enhancing umami, resulting in comprehensive quality. As a result, the present invention has been completed.
The present invention prepares a tea leaf (contact solution) in which enzyme activity remaining tea leaves are combined with sodium ascorbate, magnesium chloride and yeast extract (contact solution), impregnated with this, impregnated with low-grade tea leaves, and holds the tea leaves on the tea leaves. A method for improving the quality of low-grade tea and green tea whose quality has been improved, characterized in that an enzyme deactivation treatment is performed after sufficient scent components are produced.
In the present invention, it is preferable that the enzyme activity remaining tea leaves are mixed with water together with sodium ascorbate, magnesium chloride and yeast extract to make a juice, and this is impregnated with low-grade tea leaves.
It has been confirmed that the quality can be optimally improved by carrying out the holding at 25 to 50 ° C. for 30 to 100 minutes.
If necessary for convenience of handling, the tea leaves may be finally dried.

According to the quality improvement method of the present invention, β-primeverosidase or the like is allowed to act to decompose glycosides to enhance the scent component, and a combination of sodium ascorbate, magnesium chloride, and yeast extract provides a refreshing light blue yellow color. It can give a green color, reduce bitterness and astringency, and increase umami. Therefore, the quality of low-grade tea can be improved with a high overall balance.
Further, when the green tea with improved quality according to the present invention is in the form of tea leaves, the extraction efficiency can be improved, especially the extraction with cold water is facilitated, and it is possible to provide cold tea in a shorter time than ever before. In addition, the manufacturing process of the packaged beverage can be simplified.

It is an example of the flowchart of the process of the quality improvement method which concerns on embodiment of this invention. It is a GC-MS chart of the scent component of the tea leaf of the present invention of Example 18. It is a GC-MS chart of the scent component of the tea leaves (autumn / winter bancha) of Reference Example 1. It is a GC-MS chart of the fragrance component of the tea leaf (green tea (new tea)) of Reference Example 2. It is a GC-MS chart of the fragrance component of the tea leaf (black tea) of Reference Example 3.

(Tea leaves to be processed)
In the present invention, any tea leaves that can act on β-primeverosidase or the like related to the scent derived from tea leaves may be used, so that all the glycosides that can act on the tea leaves to be treated remain. Although it is included, the improvement effect is sought for low-grade tea that has been plucked and processed, including the bactericidal treatment, typically Nibancha, Sanbancha, Akiyubanbancha, etc., which are assumed in the present invention. .
It should be noted that “low quality” of low-grade tea should not be understood in a narrow sense, and any that would improve quality is applicable.
In addition, the relationship between the tea leaves and the tea leaves constituting the contact liquid described later is not particularly limited, and varieties and picking times may be different.

(Contact liquid)
Enzyme activity remaining tea leaves are combined with water together with sodium ascorbate, magnesium chloride and yeast extract.

Enzyme activity remaining tea leaves mean tea leaves that have not been subjected to enzyme deactivation treatment, usually referred to as blue-killing treatment, typically fresh tea leaves. The variety is not limited, and it is sufficient to be a low-grade tea. This tea leaves with enzyme activity contain β-primeverosidase involved in the production of fragrance components.
If attention is paid only to the above enzyme, some of them are derived from microorganisms, but when carrying out the method of the present invention, the green chlorophyll contained together is used, and the retention temperature is relatively low, so thermal stability is not so required. Therefore, the enzyme activity remaining tea leaves are used.
The mixing ratio of the enzyme activity remaining tea leaves and the tea leaves to be improved is preferably 1:50 to 50 in terms of dry matter. This is because, within this range, the refreshing green scent of green tea and the floral scent of black tea can be surely expressed without the scent being sufficient and strong. 1 to 25-40 is more preferable.

Sodium ascorbate is added to suppress browning due to oxidation of catechin by suppressing the action of polyphenol oxidase inevitably contained in the tea leaves with residual enzyme activity.
Magnesium chloride is added to prevent fading of green chlorophyll.
As for the usage-amount of sodium ascorbate with respect to enzyme activity residual tea leaves, 1.5-4.5 mass% is preferable. This is because, within this range, sufficient coloring can be reliably realized without affecting the flavor. 2.0-3.5 mass% is more preferable.
As for the usage-amount of magnesium chloride hydrate with respect to enzyme activity residual tea leaves, 1.0-5.0 mass% is preferable. This is because, within this range, sufficient coloration can be reliably realized without increasing the bitterness.

Yeast extract is added to produce umami.
Therefore, the yeast extract is preferably rich in glutamic acid. Yeast extract also contains protein peptides, which act in the direction of preventing browning due to oxidation of catechins, like sodium ascorbate.
As a standard of the appropriate amount of yeast extract, it can be judged by the total amount of free amino acids in tea leaves. The total amount of free amino acids is preferably 5 to 50 mg / g. If the amount is less than 5 mg / g, the effect may be insufficient. On the other hand, if the amount exceeds 50 mg / g, the yeast extract odor becomes strong and tends to affect the flavor.
The total amount of free amino acids can be measured by the post-column fluorescence detection method of Shimadzu Corporation or the AccQ • Tag method of Waters.

The form of yeast extract includes liquid, paste, and powder (including those dried by adding dextrin and the like), and any of them can be used, but the paste is preferable for handling.
However, although depending on the composition of the yeast extract, if the amount other than the extract is too large, the compatibility is affected. The amount of yeast extract used relative to the enzyme activity remaining tea leaves is preferably 20 to 60% by mass, more preferably 35 to 45% by mass in the case of a paste having fluidity and an extract content of 65% by mass. If the amount is less than 20% by mass, the effect may be insufficient. On the other hand, if the amount exceeds 60% by mass, the yeast extract odor becomes strong and the flavor tends to be adversely affected.
As paste products, Asahi Food & Healthcare “Hyper Mist HG-Ps”, Kirin Kyowa Foods “Yeast Extract Kyowa U”, “Yeast Extract Kyowa L”, Kojin Co., Ltd. “Ajitop” and the like.
Examples of those that are rich in glutamic acid include “Hypermist HG-Ps” and “Ajitop”.

  In the present invention, other components can be used in combination as long as the functions of the components and the desired final product form are not impaired. What is used in combination depends on the application and the like, and examples thereof include sugars, sweeteners, seasonings, fragrances, coloring agents, preservatives and the like.

  The contact solution may be stored frozen and thawed when used. In this case, the amount of water used for preparing the contact liquid may be small, and water may be added when impregnating the low-quality tea leaves to be improved.

(Implementation of quality improvement method)
In the present invention, low quality tea to be improved is brought into contact with the contact liquid described above.
A preferred procedure is that shown in FIG.
In order to accelerate the reaction, it is preferable to grind the remaining tea leaves with enzyme activity and grind the water together with sodium ascorbate, magnesium chloride and yeast extract into a juice-like contact liquid.
The amount of water used for the enzyme activity remaining tea leaves is preferably 10 to 20 times, more preferably 14 to 18 times the weight of the enzyme activity remaining tea leaves. If it is less than 10 times, it is difficult to uniformly impregnate the low-grade tea leaves with the contact liquid, and if it exceeds 20 times, the low-quality tea leaves become sticky and the drying cost increases.

The contact liquid is impregnated with low-grade tea leaves and brought into contact with each other to maintain a uniform mixture.
When impregnating and bringing into contact, pulverizing the low-quality tea leaves to be improved increases the chance of contact with the contact liquid, and the taste and aroma are likely to improve. Therefore, when the desired final product form does not need to maintain the form of tea leaves such as beverages, it is recommended to grind the low-quality tea leaves.

In order to maintain the contact state, in order to make the dispersion uniform and allow the fermentation to proceed uniformly and in a short time, the thickness of the mixture is preferably reduced and flattened, more preferably 1 cm or less.
Although the container used for holding is not particularly limited, a flat object such as a tray or a flat bag is preferable. Moreover, it is preferable to seal and hold | maintain in order not to volatilize the fragrance component produced by fermentation.
In order to carry out the holding step continuously, the mixture may be conveyed at a constant speed in a temperature-controlled room. When a container is not used, for example, a temperature-controlled extruder can be used.
The holding is preferably performed with air shut off. This is because browning occurs easily when there is contact with new air.

The contact holding is carried out at 25 to 50 ° C., preferably 30 to 45 ° C., for 30 to 100 minutes, preferably 40 to 80 minutes.
This is because if the temperature is low, it takes time to develop the scent, and if it is high, the scent is weakened. This is because if the time is short, the expression of the fragrance is weak, and if the time is long, the taste is adversely affected.

  In order to terminate the reaction, the mixture can be enzyme-inactivated to obtain the hydrated tea leaves of the present invention. The means for deactivating the enzyme is not particularly limited. For example, hot water can be poured or a microwave oven can be used. This process can also serve as sterilization.

(Qualified water-containing tea leaves)
The hydrated tea leaves according to the present invention generally have enhanced scent components such as linalool, phenylethyl alcohol, benzyl alcohol, green leaf alcohol, nerol, β-ocimene, 1-hexanol, hexanal, 2-heptenal, and methyl salicylate.
Linalool (lavender scent), phenylethyl alcohol (rose scent), benzyl alcohol (almond scent), nerol (rose scent), β-Ocimene is a floral scent that contains a lot of black tea. is there.
Green leaf alcohol (green fragrance), 1-hexanol, hexanal, and 2-heptenal are green fragrance components that make green tea feel. Methyl salicylate is a scent component that provides a cool feeling.
The above-mentioned components are hardly included in the autumn / winter bancha, which is a typical low-grade tea, or a very small amount even if included. Green tea (new tea) contains only a small amount of benzyl alcohol, green leaf alcohol, and 2-heptenal.
The color and taste are also improved.
Therefore, the water-containing tea leaves according to the present invention are unprecedented in that the aroma, color, and taste of green tea are enhanced and the aroma of black tea is added. Moreover, the high-quality tea is made from low-grade tea. Is an epoch-making thing.

(Preservation of water-containing tea leaves with improved quality)
The obtained hydrated tea leaf may be used in the hydrated state as it is, but is preferably dried for the convenience of storage, more preferably to a moisture content of about 10% or less, and further to 5% or less. . The means for drying is not particularly limited, but in order to maintain the aroma and extraction efficiency obtained in the present invention, it is preferable to dry at a low temperature of 60 ° C. or less, and more preferably 30 ° C. or less. In order to promote drying at a low temperature, vacuum drying is preferred. When drying under reduced pressure, the green color becomes white and the appearance of the tea leaves is improved by several steps, which has the unexpected effect.
The drying container is not particularly limited, but a flat container such as an aluminum or steel tray is preferable for uniform drying.

(Use of water-containing tea leaves)
The tea leaves improved by the quality improvement method of the present invention can be used for container-packed beverages, leaf teas, powdered teas, tea bags, food materials and the like, and the hydrous tea leaves may be processed depending on the uses.
For example, when the obtained hydrated tea leaves are used for a container-packed beverage or the like, the extraction liquid is used after the extraction process. The extraction process has been confirmed with suitable conditions, and will be described in detail below.

(Extraction processing of hydrous tea leaves)
In the extraction treatment, the water content is preferably adjusted to 50 to 90%, and more preferably adjusted to 65 to 80%. This is because within that range, a good balance of fragrance, color, taste and umami can be obtained.
The moisture content is calculated as follows.
Moisture content (%) = [(tea leaf weight−dry weight in tea leaf) / tea leaf weight] × 100

The extraction treatment is preferably set in cold water (0 to 40 ° C.) for a short time (30 minutes or less). The temperature is more preferably 15 to 30 ° C. and the time is preferably 1 to 10 minutes.
Aroma components such as green leaf alcohol, benzyl alcohol and linalool are extracted more than hot water extraction, while components with bitter taste such as epigallocatechin gallate, epicatechin gallate, gallocatechin gallate and catechin gallate are significantly reduced. Because.
The extraction condition has an advantage that the manufacturing process of the packaged beverage can be simplified as compared with the conventional conditions.

In particular, when drinking, it is preferable to adjust to be linalool 5 to 100 ppb, benzyl alcohol 5 to 200 ppb, green leaf alcohol 5 to 200 ppb.
When linalool is less than 5 ppb, refreshing is insufficient, and when it exceeds 100 ppb, some people feel persistent. If the benzyl alcohol is less than 5 ppb, the scent lacks the base feeling, and if it exceeds 200 ppb, the scent balance is lost. This is because when the green leaf alcohol is less than 5 ppb, it does not feel fresh, and when it exceeds 200 ppb, it may feel blue.
More preferably, linalool is 10 to 50 ppb, benzyl alcohol is 10 to 100 ppb, and green leaf alcohol is 10 to 100 ppb.

Furthermore, it is preferable to adjust so that it may become phenyl ethyl alcohol 10-500ppb and methyl salicylate 1-20ppb. If the phenylethyl alcohol is less than 10 ppb, the floral feeling is insufficient, and if it exceeds 500 ppb, a slightly unnatural aroma is obtained. When methyl salicylate is less than 1 ppb, refreshing is insufficient, and when it exceeds 20 ppb, the aroma balance is lost.
More preferred are phenylethyl alcohol 15 to 200 ppb and methyl salicylate 1 to 5 ppb.

  Furthermore, when drinking as cold tea, it is preferable to adjust so that content of the catechin which has a gallate group may be 250 ppm or less. This is because when it exceeds 250 ppm, the bitterness is strongly felt.

  Examples of the present invention will be described below. However, the scope of the present invention is not limited to the following examples, and changes in design and the like within the scope of the present invention are also included in the invention.

[Example 1]
5 g of frozen second tea enzyme activity remaining tea leaves (corresponding to 1 g as dry matter), magnesium chloride (hexahydrate) (Wako first grade, Wako Pure Chemical Industries, Ltd.) 125 mg, sodium L-ascorbate (BASF Japan) 125 mg, 2 g of yeast extract paste (Asahi Food and Healthcare, trade name: Hyper Mist HG-Ps, extract content 65%) and 80 ml of water were placed in a mixer (MILLSER IFM-600D, manufactured by Iwatani Corporation) and stirred. The enzyme activity remaining tea leaves were crushed to obtain enzyme activity remaining tea leaves juice.
Next, 30 g of dry autumn / winter bancha was impregnated and mixed with the enzyme activity remaining tea leaf juice. A mixture of the enzyme activity remaining tea leaf juice and dried autumn / winter bancha is placed in a beaker, covered with aluminum foil, placed in a thermostatic device (DKM600, manufactured by Yamato Kagaku Co., Ltd.), kept in contact with the product at 40 ° C. for 60 minutes, Obtained.
The water-containing tea leaves were inactivated with a microwave oven (manufactured by Panasonic Corporation, NE-EH211) at 500 W for 20 seconds.
The enzyme-inactivated water-containing tea leaves were thinly spread on an aluminum tray and dried in a dryer at 60 ° C. until the water content became 5% to obtain the dry tea leaves of the present invention.
60 ml of hot water was added to 1 g of the dried tea leaves of the present invention and drunk.

In the following comparative examples, the dried tea leaves of the present invention were obtained in the same manner as in Example 1 except that only the specified points were changed.
[Comparative Example 1] Tea leaves with residual enzyme activity were not used.
[Comparative Example 2] Magnesium chloride was not used.
[Comparative Example 3] Sodium L-ascorbate was not used [Comparative Example 4] No yeast extract was used.

[Example 2]
A dried tea leaf of the present invention was obtained in the same manner as in Example 1 except that the contact was maintained at 25 ° C.
[Example 3]
A dried tea leaf of the present invention was obtained in the same manner as in Example 1 except that the contact was maintained at 50 ° C.
[Example 4]
A dried tea leaf of the present invention was obtained in the same manner as in Example 1 except that the contact was maintained for 35 minutes.
[Example 5]
A dried tea leaf of the present invention was obtained in the same manner as in Example 1 except that the contact was maintained for 95 minutes.
[Example 6]
A dried tea leaf of the present invention was obtained in the same manner as in Example 1 except that the contact was maintained at 15 ° C.
[Example 7]
A dry tea leaf of the present invention was obtained in the same manner as in Example 1 except that the contact was maintained at 55 ° C.
[Example 8]
A dried tea leaf of the present invention was obtained in the same manner as in Example 1 except that the contact was maintained for 25 minutes.
[Example 9]
A dried tea leaf of the present invention was obtained in the same manner as in Example 1 except that the contact was maintained for 110 minutes.

[Example 10] Example of cryopreserved tea leaves with enzyme activity remaining 5 g tea leaves with remaining enzyme activity, magnesium chloride (hexahydrate) (Wako first grade, Wako Pure Chemical Industries, Ltd.) 125 mg, sodium L-ascorbate 125 mg (manufactured by BASF Japan), yeast extract paste (manufactured by Asahi Food and Healthcare, trade name: Hyper Mist HG-Ps, extract 65%), 2 g, 10 ml of water and mixer (MILLSER IFM, manufactured by Iwatani Corporation) -600D) and stirred, and the enzyme activity remaining tea leaves were crushed to obtain enzyme activity remaining tea paste with a small amount of water (water content).
After freezing, 70 ml of water was added and thawed to obtain a tea leaf juice with residual enzyme activity. Next, 30 g of dry autumn / winter bancha was impregnated and mixed with the enzyme activity remaining tea leaf juice. The enzyme activity remaining tea leaf juice and the dried autumn / winter bancha mixture were covered with aluminum foil in a beaker, placed in a thermostatic device (DKM600, manufactured by Yamato Kagaku Co., Ltd.), and kept at a product temperature of 40 ° C. for 60 minutes to obtain hydrous tea leaves.
The water-containing tea leaves were inactivated with a microwave oven (manufactured by Panasonic Corporation, NE-EH211) at 500 W for 20 seconds.
The enzyme-inactivated water-containing tea leaves were thinly spread on an aluminum tray and dried in a dryer at 60 ° C. until the water content became 5% to obtain the dry tea leaves of the present invention.
60 ml of hot water was added to 1 g of the dried tea leaves of the present invention and drunk.
[Example 11] Example of spray-drying The hydrous tea leaves prepared in Example 1 were inactivated by using a microwave oven (manufactured by Panasonic Corporation, NE-EH211) at 500 W for 20 seconds.
100 g of hot water was added to 30 g of hydrous tea leaves deactivated with the enzyme to extract tea components, and the extract was spray dried using a mini spray dryer (Pulvis GB22 manufactured by Yamato Kagaku Co., Ltd.) to obtain a powder.
60 ml of hot water was added to 0.3 g of the obtained powder and drunk.
[Example 12] Example of further pulverization after impregnation mixing After impregnating and mixing dry autumn / winter bancha with enzyme activity remaining tea leaf juice, the mixture was stirred in a mixer (MILLSER IFM-600D manufactured by Iwatani Corporation), and tea leaves were further pulverized. Obtained the dried tea leaves of the present invention in the same manner as in Example 1.
60 ml of hot water was added to 1 g of dried tea leaves and drunk.
[Example 13] Example of drying under reduced pressure The dried tea leaves of the present invention were obtained in the same manner as in Example 1 except that the enzyme-inactivated water-containing tea leaves were dried at 25 ° C using a vacuum dryer (ADVANTEC, DRV422DC). Obtained.
60 ml of hot water was added to 1 g of dried tea leaves and drunk.
[Example 14] Example of holding in a plastic bag The mixture was put in a polyethylene bag, sealed, stretched to a thickness of about 1 cm, held, transferred to an aluminum tray and dried, and then the same as in Example 1. Thus, dried tea leaves of the present invention were obtained.
60 ml of hot water was added to 1 g of dried tea leaves and drunk.
[Examples 15 to 17] Use examples of different yeast extracts As yeast extracts, "Yeast Extract Kyowa U" (Example 15), "Yeast Extract Kyowa L" (Example 16), Kojinsha, manufactured by Kirin Kyowa Foods Co., Ltd. A dry tea leaf of the present invention was obtained in the same manner as in Example 1 except that “Ajitop” manufactured in Example 17 was used.
60 ml of hot water was added to 1 g of dried tea leaves and drunk.

[Comparative Example 5]
A dried tea leaf of a comparative example was obtained in the same manner as in Example 1 except that 500 mg of a commercially available scent-generating enzyme (“Aromase” manufactured by Amano Enzyme Co., Ltd.) was used instead of the frozen second tea enzyme activity remaining tea leaf.
60 ml of hot water was added to 1 g of dried tea leaves and drunk.

[Reference Example 1]
Autumn / winter bancha (raw material of Example 1, produced in Makinohara City, 2011, manufactured by Kisakuen)
60 ml of hot water was added to 1 g of dried tea leaves and drunk.
[Reference Example 2]
Green tea (new tea) (2012 Makinohara City, Kisakuen)
60 ml of hot water was added to 1 g of dried tea leaves and drunk.
[Reference Example 3]
Black tea (from 2010 Darjeeling, made by Mitsui Norin)
60 ml of hot water was added to 1 g of dried tea leaves and drunk.

(Evaluation)
Evaluation method: Five panelists evaluated the items of aroma, bitterness, umami, and light blue with respect to autumn / winter bancha in Reference Example 1. Evaluation was made by summing up the evaluation scores of 5 people (with significant effect = 2 points, with some effect = 1 point, without effect = 0 point, inferior = −1 point) and classified as follows.
A: Significant effect (9 points or more) A to B: Some effect (7-8 points)
○: Somewhat effective (5-6 points)
Δ: No effect (less than 5 points)
Comprehensive evaluation
◎: Excellent (35 points or more) ◎ to ○: Somewhat excellent (32 to 34 points) ○: Somewhat excellent (24 to 31 points) △: Normal (less than 24 points)
As shown in Table 1 below, it was confirmed that only the examples succeeded in improving the quality comprehensively.

[Example 18] Analysis of fragrance component In Example 12, water-containing tea leaves were obtained without drying.
7.2 g of the above-mentioned hydrated tea leaves (2 g in terms of dry tea leaves), 2 g of raw autumn / winter bancha (manufactured in Makinohara City in 2011), 2 g of green tea (manufactured in Makinohara City in 2012), and 2 g of black tea (2010 Darjeeling) Extracted with 200 ml of boiling hot water for 2 minutes.
The extract was analyzed using a gas chromatograph mass spectrometer (GC-MS) (Agilent GC7890A / 5975C) under the following conditions.
・ Analysis conditions 100 μl each of LVFET (Large Volume
Volatilization is performed by Full Evaporation Technique), GC analysis Carrier gas Helium 1.8ml / min
Column DB-WAX (0.25 mm × 60 m, film thickness 0.25 μm)
Temperature rising condition Hold at 40 ° C for 5 minutes, then heat up to 250 ° C at 5 ° C / min

An analysis chart is shown in FIGS.
As shown in the figure, in the present invention, more scent components were detected than the raw materials of autumn / winter bancha and green tea (new tea). Among these, linalool, phenylethyl alcohol, benzyl alcohol, green leaf alcohol, and methyl salicylate significantly increased.

Table 2 shows the scent component content in the extract.
The content was calculated by quantifying the aroma component concentration in the extract using a standard reagent (manufactured by Sigma-Aldrich).

表２に示したように本発明ではリナロール、フェニルエチルアルコール、ベンジルアルコール、青葉アルコール、サリチル酸メチルが顕著に増加した。

As shown in Table 2, in the present invention, linalool, phenylethyl alcohol, benzyl alcohol, green leaf alcohol, and methyl salicylate significantly increased.

[Example 19] Confirmation of extraction efficiency 7.2 g of hydrous tea leaves of Example 18 (2 g in terms of dry tea leaves) and 2 g of the dry tea leaves were extracted with cold water at 20 ° C and 200 ml of hot water at 100 ° C for 2 minutes. In addition, green tea (manufactured by Kisakuen) was similarly extracted for comparison.
The concentration of the extract was measured by the Brix value (RX-DD7α-TEA manufactured by ATAGO was used. Measurement temperature 20 ° C.). For evaluation as a beverage, the Brix value of each extract was adjusted to 0.3 Brix%, and the scent component content was analyzed by the GC-MS method.
The measurement results are shown in Table 3.
As shown in Table 3, the dry tea leaves of the present invention and the green tea for comparison could be extracted only up to 0.173 Brix% and 0.116 Brix% by this cold water extraction method, so the effect of being water-containing was shown. Moreover, when the dried tea leaves were compared, it was estimated that the extraction efficiency of the dried tea leaves of the present invention was excellent and the action effect of the enzyme activity remaining tea leaves was obtained.
In addition, caffeine and catechins in the aqueous tea leaf extract of the present invention were measured using a high-performance liquid chromatograph (manufactured by Water, Acquity UPLC).
The measurement results are shown in Table 4.

＊アスコルビン酸ナトリウム、塩化マグネシウム及び酵母エキスの所定量のイオン交換水溶液のＢｒｉｘ％値は、０．０１９であった。

* The Brix% value of a predetermined amount of ion exchange aqueous solution of sodium ascorbate, magnesium chloride and yeast extract was 0.019.

As shown in Table 3, the hydrated tea leaves of the present invention were rich in aromatic fragrance components such as linalool, benzyl alcohol, and green leaf alcohol by cold water extraction.
As shown in Table 4, the water-containing tea leaves of the present invention, the components exhibiting bitter and astringent taste such as epigallocatechin gallate, epicatechin gallate, gallocatechin gallate, catechin gallate by cold water extraction are significantly reduced compared to hot water extraction, It was possible to provide cold tea with a bitter and astringent taste and a black tea-like aroma.

  By increasing the added value of low-grade tea, farmers can be motivated to produce and promote the tea industry.

Claims (6)

  Enzyme activity remaining tea leaves were prepared in water with sodium ascorbate, magnesium chloride and yeast extract, and impregnated with low-grade tea leaves and kept in contact with them to generate sufficient scent components from the tea leaves A method for improving the quality of low-grade tea, characterized by performing an enzyme deactivation treatment later.   The enzyme activity remaining tea leaves, which are mixed with water with sodium ascorbate, magnesium chloride and yeast extract, are pulverized into juice, which is impregnated with low-grade tea leaves and brought into contact therewith. How to improve the quality of low-grade tea.   The method for improving the quality of low-grade tea according to claim 1, wherein the holding is performed at 25 to 50 ° C. for 30 to 100 minutes.   Green tea whose quality has been improved by the method according to any one of claims 1 to 3.   The green tea with improved quality according to claim 4, characterized in that it is made from low-grade tea leaves and contains linalool, benzyl alcohol, green leaf alcohol, phenylethyl alcohol, and methyl salicylate.   6. The green tea with improved quality according to claim 4, wherein the green tea is leaf tea, powdered tea, tea bag or container-packed beverage.

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