JP2006109797A - Method for producing green tea extract and green tea extract - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a green tea extract having increased fragrance and decreased bitter taste. <P>SOLUTION: The method for producing a green tea extract comprises the extraction of green tea leaves with 10-20 pts. mass of hot water of 55-75°C based on 1 pt. mass of the tea leaf for 3-5 min, the removal of tea dregs to obtain a green tea extract liquid, the addition of β-primeverosidase in an amount of 0.01-0.05 mass% based on the extract liquid and the enzymatic treatment of the liquid at 35-45°C for 0.5-3 hr. The invention further provides a green tea extract produced by the method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for preparing a green tea extract and a green tea extract obtained thereby.

The consumption of green tea drinks has been steadily increasing due to the recent health consciousness of consumers. Various types of green tea beverages have been studied in the past, and many types of products have been produced in the past, such as pouring hot water into tea leaves, and in recent years filled with cans and plastic bottles. Yes.
In order to produce a good green tea extract from green tea which is a raw material in these products, various studies have been conventionally conducted. However, there is a problem that when the temperature at the time of green tea extraction is too low, the taste is too light, and when the temperature is too high, a bitter taste is produced. Even if the consumer's palatability is actually examined, there is a tendency to prefer a product having a delicious taste and a weak bitter taste. From such a viewpoint, the prior art has been developed with an emphasis on taste.
On the other hand, the scent of green tea is very dilute, and there is a problem that sufficient aroma cannot be obtained by extraction with normal warm water, and development focusing on the scent of green tea extract has been carried out, but it is still insufficient State.
Recently, in order to solve these problems, various methods for improving aroma by performing enzyme treatment on green tea leaves and green tea extracts have been studied (see, for example, Patent Document 1 and Patent Document 2).
However, for example, even when a green tea extract is prepared using the enzyme described in Patent Document 1, the amount of aroma increases, but the problem remains that bitterness and astringency become stronger.
International Publication No. 00/18931 Pamphlet WO 02/13560 pamphlet

  An object of the present invention is to provide a green tea extract having high palatability with enhanced aroma and reduced bitterness.

As a result of intensive studies, the present inventors were able to achieve the above object by treating a green tea extract prepared under specific extraction conditions with a specific enzyme under specific conditions. .
That is, the present invention is as follows.

(1) After adding 10 to 20 times the mass of hot water at 55 to 75 ° C. and extracting for 3 to 5 minutes with respect to the green tea leaves, the green tea extract obtained by removing the tea husks is added to the green tea extract. A method for preparing a green tea extract comprising adding 0.01 to 0.05% by mass of β-primeverosidase and performing an enzyme treatment at 35 to 45 ° C. for 0.5 to 3 hours.
(2) A green tea extract produced by the preparation method described in (1) above.

  According to the present invention, a method for preparing a green tea extract with enhanced aroma and reduced bitterness and astringency can be provided.

  Hereinafter, the present invention will be described in detail.

  The green tea leaf in the present invention is a non-fermented tea leaf in which the picked tea leaf or tea bud is immediately heated to deactivate the enzyme contained in the leaf to keep the green color. As a heating means, there are a steaming method and a frying method. Specifically, green tea leaves include steamed non-fermented tea such as Sencha, Bancha, Gyokuro, Kabusecha, Tencha, Hojicha, etc., and fermented non-fermented tea such as Ureshino tea, Aoyagi tea, Chinese green tea, etc. It can be illustrated.

The warm water used for extraction in the present invention may be simple warm water, but ion-exchanged water from which substances dissolved as ions in water have been removed by passing through an ion-exchange resin, and neutral by utilizing its boiling point by distillation. Distilled water from which impurities such as substances, organic substances, and garbage are removed, and groundwater collected from specific water sources is used as raw water, and natural water and natural water that are not subjected to physical or chemical treatment other than precipitation, filtration, and heat sterilization Natural mineral water with mineralized groundwater (natural carbon dioxide is dissolved and foaming groundwater is included) as raw water, usually about 20 mg / l of gas (air) is dissolved in this gas. Degassed water from which ascorbic acid has been removed, ascorbic acid-dissolved water to which ascorbic acid has been added in advance, and constant using appropriate acid and alkali Can also be used such as pH adjustment water adjusted to pH (including also buffer).
The temperature of warm water used for extraction is in the range of 55 to 75 ° C, and 70 ° C is particularly preferable. The extraction time is 3 to 5 minutes, and 3 minutes is particularly preferable.
Extraction at a hot water temperature lower than 55 ° C can reduce bitterness and aroma, but the amount of fragrance is small. Conversely, extraction at a high temperature exceeding 75 ° C increases the amount of fragrance, but the bitterness and taste are strong and the palatability is reduced. .
If the extraction time is less than 3 minutes, the bitter and astringent taste can be reduced, but the amount of fragrance is small. Conversely, if the extraction time exceeds 5 minutes, the amount of fragrance increases, but the bitter and astringent taste becomes strong. In either case, palatability is reduced.
The hot water used for the extraction is added 10 to 20 times by mass with respect to the green tea leaves. If the amount is less than 10 times the mass, sufficient extraction is difficult to be performed. Conversely, if the amount is more than 20 times the mass, the bitter taste tends to increase.

  The method for extracting green tea in the present invention may be a method generally used when extracting green tea. For example, after charging green tea leaves in an extraction kettle and immersing them in a predetermined amount of water for a certain period of time to remove the tea husk and obtaining an extract, or after filling the extraction tank with green tea leaves, a constant flow of water is sent. And a method for obtaining a predetermined amount of the extract.

  Examples of the method for removing tea leaves in the present invention include filtration with a metal net or cloth, centrifugal separation, and vibration sieve. Since rapid processing is desired to suppress the change in flavor, filtration with a metal net or cloth or centrifugation is preferable. In order to obtain a green tea extract, since a normal filtration step is included after removing the tea husk, there is no particular problem even if a residue is present in the green tea extract at this stage.

In the present invention, the green tea extract is subjected to an enzyme treatment by adding a plant (tea leaf or the like) or fungus-derived β-primeverosidase. Here, β-primeverosidase is an enzyme classified into β-glycosidase described in International Publication No. 00/18931, and disaccharide glycosides, particularly β-primeveroside and analogs thereof in disaccharide units. Has the effect of cutting.
As an enzyme treatment condition with β-primeverosidase, 0.01 to 0.05% by mass of β-primeverosidase was added to the green tea extract, and the enzyme was incubated at 35 to 45 ° C. for 0.5 to 3 hours. It is necessary to perform processing. In this case, it is preferable to use β-primeverosidase having an enzyme activity of 63.5 to 6350 units / g. Here, 1 unit is the amount of enzyme necessary to release 1 μmol of p-nitrophenol in 1 minute. The treatment conditions are particularly preferably 37 ° C. and 0.8 hours.
In the present invention, by combining the specific extraction condition and the specific treatment condition with a specific enzyme, a highly palatable green tea extract with enhanced aroma and reduced bitterness can be prepared.
In the present invention, after the enzyme treatment, it is preferable to perform a heat treatment that serves as both enzyme deactivation and sterilization. The heat treatment condition may be a generally performed method, for example, a method of immersion heating at 90 ° C. for 10 minutes.

  After the heat treatment that serves both to deactivate and sterilize the enzyme, it is cooled, and a clear green tea extract can be obtained by separating by appropriately adopting separation means such as centrifugation, filter paper filtration, and auxiliary agent filtration. In addition, the obtained green tea extract can also be made into the form of a concentrate by an appropriate concentration means. Each step of cooling, separation and concentration can be performed by known means.

In the present invention, the green tea extract obtained by the above method can be used for beverages, for example.
When the green tea extract of the present invention is used for beverages, for example, the green tea extract is diluted with ion-exchanged water and the like, adjusted to pH with sodium bicarbonate water and filled into a container, and then subjected to general sterilization treatment to obtain a product. Examples of the container to be filled include conventionally known cans, PET bottles, paper packs and the like. Moreover, you may add vitamin C, a fragrance | flavor, etc. to the preparation stage before filling as needed. Sterilization when filling the container with the extract is performed by retort sterilization under conditions such as 121 ° C for 10 minutes if it is made of aluminum or steel metal, and 135 ° C for 30 seconds if the container is a paper pack. In general, high-temperature and short-time sterilization is performed under such conditions.
In the case of a PET bottle, the container may be sterilized in advance, and the extract may be aseptically filled after being sterilized at a high temperature such as 135 ° C. for 30 seconds for a short time.

Examples of the present invention and comparative examples are shown below, but the present invention is not limited to the following examples of the present invention.
[Reference Example and Invention Example 1]
Extract 25 g of green tea leaves (tea leaves from Marubeni Foods Co., Ltd.) into a glass beaker with a capacity of 1000 ml, add 500 ml of ion-exchanged water at 70 ° C. and extract for 3 minutes. 300 g of a liquid was obtained. This green tea extract was used as a reference example.
The obtained green tea extract was transferred to a glass bottle with a screw cap, and 30 mg (0.01% by mass) of β-primeverosidase (Amano Enzyme Co., Ltd., using 1030 unit / g) was added, and the temperature was kept constant. After carrying out the enzyme treatment at 37 ° C. for 0.8 hours in the tank, the green tea extract was obtained as Invention Example 1 by heat treatment at 90 ° C. for 10 minutes.

[Comparative Example 1]
Except for changing the addition amount of β-primeverosidase 30 mg in Example 1 of the present invention to 4.37 units, the enzyme treatment temperature 37 ° C to 55 ° C, and the treatment time 0.8 hours to 24 hours, Green tea extract was obtained by the same method.

[Sensory Evaluation 1] Sensory Evaluation of Invention Example 1 and Comparative Example 1 The green tea extract obtained in Invention Example 1 and Comparative Example 1 was drinkable (0.2 Brix%) (Brix meter: ATAGO COMPANY RX-5000). Was used), and 5 professional panelists evaluated the fragrance and taste based on the following evaluation criteria.
Evaluation criteria for fragrance (for scent enhancement effect)
1 point: No scent enhancement effect.
2 points: A slight scent enhancement effect is observed.
3 points: The effect of enhancing the fragrance is clearly recognized.
4 points: The effect of enhancing the fragrance is noticeable.
Evaluation criteria for taste (for bitterness and astringency)
1 point: The bitter taste is very strong.
2 points: Strong bitter taste.
3 points: Slightly strong bitter taste.
4 points: The bitter taste is weak.
The results are shown in Table 1. (The numerical values in the table below are expressed as evaluation average values.)

  As is clear from Table 1, in Comparative Example 1, although the aroma is strong, the bitter and astringent taste has become very strong. On the other hand, in Example 1 of the present invention, the aroma was enhanced to the same extent as in Comparative Example 1, and the enhancement of bitterness and astringency by the enzyme treatment was remarkably suppressed, and the palatability was high in both aroma and taste.

[Invention Example 2]
A green tea extract was obtained by the same method as in Invention Example 1 except that the temperature of 70 ml of ion-exchanged water for obtaining a green tea extract from green tea leaves in Invention Example 1 was changed to 55 ° C.

[Invention Example 3]
A green tea extract was obtained in the same manner as in Invention Example 1, except that the temperature of 70 ml of ion-exchanged water used for obtaining a green tea extract from green tea leaves in Invention Example 1 was changed to 75 ° C.

[Invention Example 4]
A green tea extract was obtained in the same manner as in Invention Example 1, except that the extraction time of 3 minutes for obtaining a green tea extract from green tea leaves in Invention Example 1 was changed to 5 minutes.

[Invention Example 5]
A green tea extract was obtained in the same manner as in Invention Example 1, except that the enzyme treatment temperature 37 ° C. of β-primeverosidase in Invention Example 1 was changed to 35 ° C.

[Invention Example 6]
A green tea extract was obtained in the same manner as in Invention Example 1, except that the enzyme treatment temperature 37 ° C. of β-primeverosidase in Invention Example 1 was changed to 45 ° C.

[Invention Example 7]
A green tea extract was obtained in the same manner as in Invention Example 1, except that 30 mg of β-primeverosidase added in Invention Example 1 was changed to 150 mg (0.05% by mass).

[Invention Example 8]
A green tea extract was obtained in the same manner as in Invention Example 1 except that the enzyme treatment time with β-primeverosidase in Invention Example 1 was changed from 0.8 hour to 0.5 hour.

[Invention Example 9]
A green tea extract was obtained in the same manner as in Invention Example 1 except that the enzyme treatment time with β-primeverosidase in Invention Example 1 was changed from 0.8 hour to 3 hours.

[Sensory Evaluation 2] Sensory Evaluation of Invention Examples 2 to 9 The green tea extract obtained in Invention Examples 2 to 9 was used at a drinking concentration (0.2 Brix%) (Brix meter: ATAGO COMPANY RX-5000 was used). After dilution, score evaluation was performed for aroma and taste by five professional panelists in the same manner as described above. The results are shown in Table 2.

  As is clear from Table 2, in Examples 2 to 9 of the present invention, the fragrance was enhanced in all cases, and the enhancement of bitter and astringent taste by the enzyme treatment was suppressed, and both palatability and taste were high. .

[Comparative Example 2]
A green tea extract was obtained in the same manner as in Invention Example 1 except that the amount of ion-exchanged water 500 ml in obtaining the green tea extract from the green tea leaves in Invention Example 1 was changed to 625 ml.

[Comparative Example 3]
A green tea extract was obtained by the same method as in Invention Example 1 except that the temperature of 70 ml of ion-exchanged water for obtaining a green tea extract from green tea leaves in Invention Example 1 was changed to 50 ° C.

[Comparative Example 4]
A green tea extract was obtained in the same manner as in Invention Example 1, except that the temperature of 70 ml of ion-exchanged water used for obtaining a green tea extract from green tea leaves in Invention Example 1 was changed to 80 ° C.

[Comparative Example 5]
A green tea extract was obtained in the same manner as in Invention Example 1, except that the extraction time of 3 minutes for obtaining a green tea extract from green tea leaves in Invention Example 1 was changed to 10 minutes.

[Sensory Evaluation 3] Sensory Evaluation of Invention Example 1 and Comparative Examples 2 to 5 The green tea extract obtained in Invention Example 1 and Comparative Examples 2 to 5 was drinkable concentration (0.2 Brix%) (Brix meter: ATAGO COMPANY) The product was diluted with a company RX-5000), and score evaluation was performed for aroma and taste by five professional panelists in the same manner as described above. The results are shown in Table 3.

  As is clear from Table 3, in Comparative Example 2, although the aroma is slightly strong, the bitter taste is strong. In Comparative Example 3, although the enhancement of bitter and astringent taste is suppressed, no significant increase in aroma is observed. In Comparative Examples 4 and 5, the aroma is strong, but the bitter and astringent taste is very strong and the palatability is low.

[Comparative Example 6]
A green tea extract was obtained in the same manner as in Invention Example 1, except that 30 mg of β-primeverosidase added in Invention Example 1 was changed to 15 mg (0.005 mass%).

[Comparative Example 7]
A green tea extract was obtained in the same manner as in Invention Example 1, except that 30 mg of β-primeverosidase added in Invention Example 1 was changed to 300 mg (0.1% by mass).

[Comparative Example 8]
A green tea extract was obtained in the same manner as in Invention Example 1, except that the enzyme treatment temperature 37 ° C. of β-primeverosidase in Invention Example 1 was changed to 20 ° C.

[Comparative Example 9]
A green tea extract was obtained in the same manner as in Invention Example 1, except that the enzyme treatment temperature 37 ° C. of β-primeverosidase in Invention Example 1 was changed to 50 ° C.

[Comparative Example 10]
A green tea extract was obtained in the same manner as in Invention Example 1 except that the enzyme treatment time with β-primeverosidase in Invention Example 1 was changed from 0.8 hour to 0.3 hour.

[Comparative Example 11]
A green tea extract was obtained in the same manner as in Invention Example 1, except that the enzyme treatment time with β-primeverosidase in Invention Example 1 was changed from 0.8 hour to 5 hours.

[Comparative Example 12]
A green tea extract was obtained in the same manner as in Invention Example 1, except that 30 mg of β-primeverosidase added in Invention Example 1 was changed to 0 mg.

[Sensory Evaluation 4] Sensory Evaluation of Invention Example 1 and Comparative Examples 6-12 After the green tea extract obtained in Invention Example 1 and Comparative Examples 6-11 was diluted to a drinking concentration (0.2 Brix%), the above In the same manner, five professional panelists scored the aroma and taste. The results are shown in Table 4.

  As is clear from Table 4, in Comparative Examples 6, 8, and 10, although the bitter and astringent taste enhancement was suppressed, no significant enhancement of the fragrance was observed. In Comparative Examples 7, 9, and 11, although the fragrance is strong, the bitter and astringent taste is very strong and the preference is low.

[Example 2]
Vitamin C (0.1 g) was added to 200 g of green tea extract extracted from the green tea extract obtained by Invention Example 1 and clarified using a filter aid, and further adjusted to a final pH of 6.2 with 5% sodium bicarbonate water. Exchange water was added to make the total amount 1000 g (0.2 Brix%) (Brix meter: ATAGO COMPANY RX-5000 was used). The mixture was heated to 80 ° C., filled in a steel can (Toyo Seikan Co., Ltd.), sealed with N ₂ gas. Retort sterilization was performed at 121 ° C. for 10 minutes to obtain a green tea beverage.

Claims (2)

  The hot water at 55 to 75 ° C. is added 10 to 20 times by mass with respect to the green tea leaves and extracted for 3 to 5 minutes. A method for preparing a green tea extract, comprising adding ~ 0.05% by mass of β-primeverosidase and performing an enzyme treatment at 35 to 45 ° C for 0.5 to 3 hours.   A green tea extract produced by the preparation method according to claim 1.