JP2008308460A - Method for purifying low gallate body of non-polymeric catechins - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for selectively acquiring a high-purity low gallate body of non-polymeric catechins by a simple means in order to lower bitter taste of beverage, etc., while containing catechins in high concentration, though it is known that the gallate body of catechins has strong bitter taste. <P>SOLUTION: The method for producing the low gallate body crystal of non-polymeric catechins comprises cooling an aqueous solution containing the gallate body-containing non-polymeric catechins in an amount of 40-90 mass% based on solid content of the catechins to ≤10°C and recovering deposited crystal by centrifugal separation, filtration and decantation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for selectively obtaining a high-purity non-polymer catechin low gallate.

  As an effect of catechin, an α-amylase activity inhibitory action and the like have been reported (for example, see Patent Document 1). In order to express such a physiological effect, it is necessary to drink 4 to 5 cups of tea per day for an adult. Therefore, in order to ingest a large amount of catechin more easily, a high concentration of catechin is added to the beverage. The technology to do was desired.

  However, since beverages containing catechins at high concentrations tend to have a strong bitterness and astringency, various techniques for reducing bitterness while containing catechins at high concentrations have been developed. As the technique, there is a method of adding a sweetener or a bitterness inhibitor.

On the other hand, as a means for improving the bitterness and astringency of tea extract, it is known that the catechin gallate body has a strong bitterness. Therefore, a method for reducing the gallate body ratio by tannase treatment (Patent Documents 2 and 3). ) Has been proposed.
JP 2002-142777 A JP 2004-321105 A JP 2005-130809 A

However, there has been a demand for a technique for suppressing bitterness and astringency that does not depend on the additive, and a technique for reducing the catelate gallate body ratio that does not depend on the tannase treatment.
Accordingly, an object of the present invention is to provide a method for selectively obtaining a high-purity non-polymer catechins low gallate by simple means.

  Therefore, the present inventor did not necessarily require the use of an enzyme or the like from the non-polymer catechins-containing composition, and as a result of studying to lower the gallate body by a simple means, unexpectedly, the non-polymer catechins were completely unexpected. When the containing aqueous solution is cooled to 10 ° C. or lower, the non-gallate form of the non-polymer catechins is selectively crystallized, so that the non-polymer catechins can be obtained by a natural fractionation method without using any organic solvent or the like. It has been found that low gallate bodies can be selectively obtained as crystals.

  That is, the present invention is a non-polymer catechin characterized by cooling an aqueous solution containing 40 to 90% by mass of solid non-polymer catechins containing gallate to 10 ° C. or less and recovering precipitated crystals. The present invention provides a method for producing a low-gallate crystal.

  According to the method of the present invention, non-polymer catechins low gallate can be efficiently purified by natural fractionation. Therefore, if this is used, a beverage containing non-polymer catechins with reduced bitterness and astringency with reduced gallate body ratio can be produced.

  In the present invention, the non-polymer catechins include non-epide catechins such as catechin, gallocatechin, catechin gallate and gallocatechin gallate and epi-catechins such as epicatechin, epigallocatechin, epicatechin gallate and epigallocatechin gallate. It is a general term.

  In the present invention, the non-polymer catechins gallate is a general term including catechin gallate, gallocatechin gallate, epicatechin gallate, epigallocatechin gallate and the like. The non-polymer catechins gallo form is a general term for gallocatechin, gallocatechin gallate, epigallocatechin, epigallocatechin gallate and the like.

  A gallate body content rate means the ratio of the gallate body in the said non-polymer catechins. Moreover, a non-epimer content rate means the ratio of the non-epimer catechin in non-polymer catechins.

  Examples of the aqueous solution containing 40 to 90% by mass of the non-polymer catechins containing a gallate body used in the method of the present invention per solid content include a green tea extract, a concentrate thereof, and a purified product thereof.

  Examples of the green tea leaf used as a raw material for the green tea extract include tea leaves made from tea leaves obtained from the genus Camellia, for example, C. sinensis, C. assamica and Yabuki species, or hybrids thereof. Any tea leaves made from the tea can be used as long as they are non-fermented tea. For example, steamed tea leaves from which raw materials can be easily procured are preferable, and examples thereof include ordinary sencha, deep-steamed sencha, gyokuro, kabusecha, tama green tea, and bancha.

  The non-polymer catechins-containing aqueous solution used in the present invention is produced under normal green tea extraction conditions. The temperature at the time of extraction from green tea leaves may be 70 ° C. to boiling water, more preferably 80 ° C. to boiling water from the viewpoint of increasing the extraction efficiency of non-polymer catechins. The amount of water when extracting from green tea leaves is preferably 5 to 60 times by weight, particularly 5 to 40 times by weight, relative to the green tea leaves. The extraction time from green tea leaves is preferably 1 to 60 minutes, more preferably 1 to 40 minutes, and further preferably 1 to 30 minutes. If the extraction time is too short, elution of the non-polymer catechins is insufficient, and if it is too long, the heat-denaturing isomerization reaction of the non-polymer catechins proceeds.

  In the present invention, JP-A-59-219384, JP-A-4-20589, JP-A-5-260907, JP-A-5-306279, Japanese Patent Application 2002-114355, Japanese Patent Application 2002-020415, etc. Concentrated products of green tea extract prepared by the method exemplified in detail in 1) may be used. Examples of commercially available products include “Polyphenone”, Mitsui Norin Co., Ltd., “Theafranc”, ITO EN Co., Ltd., and “Sunphenon”, Taiyo Kagaku Co., Ltd. In addition, it can also be used in column purified products and chemically synthesized products. The form of the concentrate of the tea extract here includes various forms such as a solid, an aqueous solution, and a slurry, but in the treatment of the present invention, it is adjusted in advance to an aqueous solution state.

  The content of non-polymer catechins in the non-polymer catechin-containing aqueous solution used in the present invention is 40 to 90% by mass per solid content from the viewpoint of ease of obtaining a low gallate product. Among these, 50 to 85% by mass, particularly 60 to 80% by mass is preferable. The gallate content in the aqueous solution is preferably 10 to 80% by mass, 11 to 50% by mass, more preferably 12 to 45% by mass, and particularly preferably 13 to 40% by mass from the viewpoint of efficiently obtaining a low gallate product. The concentration of non-polymer catechins in the aqueous solution used is preferably 5 to 50% by mass, 5 to 35, more preferably 8 to 35% by mass, and particularly preferably 10 to 20% by mass. In addition, the non-polymer catechins-containing aqueous solution used as a raw material in the following cooling step is preferably subjected to tannase treatment in order to reduce the gallate body ratio to some extent in advance. The aqueous solution defined here also includes an organic solvent aqueous solution such as an ethanol aqueous solution.

  In the present invention, the non-polymer catechin-containing aqueous solution is adjusted to 10 ° C. or lower. The cooling temperature is preferably −30 to 10 ° C., particularly preferably −20 to 9 ° C. from the viewpoint of preferentially crystallizing the non-gallate body. The cooling time is 2 hours or longer, more preferably 24 hours or longer, further preferably 72 hours or longer, particularly preferably 90 days or longer, and most preferably half a year or longer. In the meantime, the aqueous solution is preferably left standing.

  By this cooling treatment, the non-gallate body is selectively precipitated as crystals. Thus, it was completely unexpected that a non-gallate body precipitated as a crystal | crystallization.

  The precipitated low gallate crystals can be easily collected by solid-liquid separation operations such as centrifugation, filtration, and decantation. Further, the crystal separation operation and the like are preferably performed at a low temperature (0 to 20 ° C.), further 0 to 10 ° C., particularly 0 to 5 ° C.

The non-gallate content of the non-polymer catechins low gallate thus obtained is preferably 60 to 100% by mass, more preferably 70 to 100% by mass, further 80 to 100% by mass, and particularly preferably 95 to 100% by mass.
Here, the “solid content” is measured by a dry weight method.

  Moreover, when this invention method was implemented using the aqueous solution from which the nonepimer content rate in nonpolymer catechins differs as a raw material, when the nonepimer content rate in a raw material is less than 15 mass%, 15 mass% It has been found that the non-epimeric content of the obtained low gallate body varies greatly with the case of more than%. That is, when a non-polymer catechin having a non-epimer content of less than 15% by mass is used as a raw material, a non-polymer catechins low gallate having a non-epimer content of 0 to 20% by mass is selective. Is obtained. On the other hand, when a non-polymer catechin having a non-epimer content of 15 to 100% by mass is used as a raw material, a non-polymer catechin low gallate having a non-epimer content of 20 to 100% by mass is obtained. It is done.

  The preferred non-epimer content of the raw material for obtaining a non-polymer catechin low gallate having a low non-epimer content is 0 to 14.9% by mass, more preferably 0 to 14% by mass, and particularly preferably 0 to 0% by mass. 13% by mass. In this case, the non-epimer content of the obtained non-polymer catechins low gallate is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, and particularly preferably 0 to 5% by mass.

  On the other hand, the preferable non-epimer content of the raw material for obtaining a non-polymer catechins low gallate body having a high non-epimer content is 15% by mass, more preferably 16% by mass, and particularly preferably 17% by mass. In this case, the non-epimer content of the obtained non-polymer catechins low gallate is preferably 20% by mass, more preferably 60% by mass, and particularly preferably 90% by mass.

  Since the non-polymer catechins obtained by the method of the present invention have a low gallate body rate, bitterness and astringency are reduced. Therefore, the gallate body ratio can be adjusted by blending with non-polymer catechins in a high concentration, for example, a green tea beverage or non-tea beverage containing 0.05 to 0.5% by mass.

(Measurement method of catechin)
The sample solution was filtered through a filter (0.45 μm), and a packed column for octadecyl group-introduced liquid chromatograph L-column TM ODS (4.6 mmφ × 250 mm) using a high performance liquid chromatograph (model SCL-10AVP) manufactured by Shimadzu Corporation. : Manufactured by the Chemical Substance Evaluation Research Organization), and the gradient method was performed at a column temperature of 35 ° C. The mobile phase A solution was a distilled aqueous solution containing 0.1 mol / L of acetic acid, the B solution was an acetonitrile solution containing 0.1 mol / L of acetic acid, the sample injection amount was 20 μL, and the UV detector wavelength was 280 nm. .
Solid content analysis Determined by dry weight method.

Example 1
(1) (Preparation of raw material aqueous solution)
The green tea extract having a catechin content of 30% by mass is subjected to tannase treatment (tannase concentration 2% by mass; reaction temperature 20 ° C.) and spray-dried by a spray drying method. The obtained powder was extracted with a mixed solvent of ethanol and water (water: ethanol = 15: 85) and then purified by adding 8 parts by weight of activated carbon to the mixture to obtain an aqueous catechin preparation solution (A )
The resulting catechin preparation (purified green tea extract) had a gallate content of 44.7% by mass. The concentration of non-polymer catechins in the solid content was 63% by mass, the solid content was 24.9% by mass, and the gallic acid concentration in the solid content was 2.7% by mass.

(2) When the obtained aqueous solution (A) (non-polymer catechin concentration in the aqueous solution of 15% by mass) was stored at −20 ° C. for 6 months and then thawed at room temperature of 25 ° C., crystals were precipitated.
When the crystals were collected and analyzed, the non-gallate form of non-polymer catechins was almost 100% by mass in the composition of non-polymer catechins.

(3) Catechin aqueous solutions having different gallate body ratios of non-polymer catechins were prepared. That is, the green tea extract having a catechin content of 30% by mass is not subjected to tannase treatment and is spray-dried by a spray drying method. Catechin was extracted from the obtained powder with a mixed solvent of ethanol and water (water: ethanol = 15: 85), and then purified by adding 8 parts by mass of activated carbon to the mixture to obtain a catechin preparation aqueous solution (B). Got. The resulting catechin preparation (purified green tea extract) had a gallate body ratio of 50.1% by mass. The concentration of non-polymer catechins in the solid content was 63.1% by mass, the solid content was 36.6% by mass, and the gallic acid concentration in the solid content was 0.3% by mass.
When these aqueous solutions (B) were cooled in the same manner as (A) by the method (2), it was found that the amount of crystals increased depending on the non-gallate body fraction (FIG. 1: the vertical axis represents the sample tube). An aqueous solution is sealed, and the amount of precipitated crystals after a certain period of time is 100% by mass from the bottom of the sample tube to the liquid surface, and the ratio of the amount of precipitated crystals is visually observed and expressed as a volume percentage. ).

(4) Catechin aqueous solutions with different gallate ratios of non-polymer catechins were prepared. That is, tannase treatment (tannase concentration 2 mass%; reaction temperature 20 ° C.) is performed on a green tea extract having a catechin content of 30 mass%, and spray dried by a spray drying method. Catechin was extracted from the obtained powder with a mixed solvent of ethanol and water (water: ethanol = 15: 85), and then purified by adding 8 parts by mass of activated carbon to the mixture to obtain a catechin preparation aqueous solution (C). Got. The resulting catechin preparation (purified green tea extract) had a gallate content of 0.4% by mass. The concentration of non-polymer catechins in the solid content was 40.4% by mass, the solid content was 36.9% by mass, and the gallic acid concentration in the solid content was 14.4% by mass. When cooled by the method 2) in the same manner as (A), it was found that the amount of crystals increased depending on the non-gallate body fraction (FIG. 1).

(5) Catechin aqueous solutions with different gallate body ratios of non-polymer catechins were prepared. That is, tannase treatment (tannase concentration 2 mass%; reaction temperature 20 ° C.) is performed on a green tea extract having a catechin content of 30 mass%, and spray dried by a spray drying method. Catechin was extracted from the obtained powder with a mixed solvent of ethanol and water (water: ethanol = 15: 85), and then purified by adding 8 parts by mass of activated carbon to the mixture to obtain a catechin preparation aqueous solution (D). Got. The resulting catechin preparation (purified green tea extract) had a gallate body ratio of 19.0% by mass. The concentration of non-polymer catechins in the solid content was 55.9% by mass, the solid content was 37.0% by mass, and the gallic acid concentration in the solid content was 10.0% by mass. When cooled by the method 2) in the same manner as (A), it was found that the amount of crystals increased depending on the non-gallate body fraction (FIG. 1).

(6) Catechin aqueous solutions with different gallate ratios of non-polymer catechins were prepared. That is, tannase treatment (tannase concentration 2 mass%; reaction temperature 20 ° C.) is performed on a green tea extract having a catechin content of 30 mass%, and spray dried by a spray drying method. Catechin was extracted from the obtained powder with a mixed solvent of ethanol and water (water: ethanol = 15: 85), and then purified by adding 8 parts by mass of activated carbon to the mixture to obtain a catechin preparation aqueous solution (E). Got. The resulting catechin preparation (purified green tea extract) had a gallate body ratio of 30.0% by mass. The concentration of non-polymer catechins in the solid content was 60.1% by mass, the solid content was 36.4% by mass, and the gallic acid concentration in the solid content was 7.3% by mass. When cooled by the method 2) in the same manner as (A), it was found that the amount of crystals increased depending on the non-gallate body fraction (FIG. 1).

(7) Catechin aqueous solutions with different gallate ratios of non-polymer catechins were prepared. That is, tannase treatment (tannase concentration 2 mass%; reaction temperature 20 ° C.) is performed on a green tea extract having a catechin content of 30 mass%, and spray dried by a spray drying method. Catechin was extracted from the obtained powder with a mixed solvent of ethanol and water (water: ethanol = 15: 85), and then purified by adding 8 parts by mass of activated carbon to the mixture to obtain a catechin preparation aqueous solution (F). Got. The resulting catechin preparation (purified green tea extract) had a gallate body ratio of 37.8% by mass. The concentration of non-polymer catechins in the solid content was 61.4% by mass, the solid content was 36.4% by mass, and the gallic acid concentration in the solid content was 5.0% by mass. When cooled by the method 2) in the same manner as (A), it was found that the amount of crystals increased depending on the non-gallate body fraction (FIG. 1).

(8) Catechin aqueous solutions with different gallate ratios of non-polymer catechins were prepared. That is, tannase treatment (tannase concentration 2 mass%; reaction temperature 20 ° C.) is performed on a green tea extract having a catechin content of 30 mass%, and spray dried by a spray drying method. Catechin was extracted from the obtained powder with a mixed solvent of ethanol and water (water: ethanol = 15: 85), and then purified by adding 8 parts by mass of activated carbon to the mixture to obtain a catechin preparation aqueous solution (G). Got. The resulting catechin preparation (purified green tea extract) had a gallate content of 44.7% by mass. The concentration of non-polymer catechins in the solid content was 62.8% by mass, the solid content was 24.9% by mass, and the gallic acid concentration in the solid content was 2.7% by mass.

(9) Catechin aqueous solutions with different gallate ratios of non-polymer catechins were prepared. Mitsui Norin "Polyphenon 70S" was used. The gallate body ratio of the catechin preparation was 62.3% by mass. The concentration of non-polymer catechins in the solid content was 81.8% by mass and powder. The gallic acid concentration in the solid content was 0.9% by mass. When the aqueous solution (H) was cooled in the same manner as (A) by the method (2), the amount of crystals depended on the non-gallate fraction. It was found to increase (FIG. 1).

(10) Catechin aqueous solutions with different gallate body ratios of non-polymer catechins were prepared. Mitsui Norin Co., Ltd. “Polyphenone 70A” was used. The gallate body ratio of the catechin preparation was 95.1% by mass. The concentration of non-polymer catechins in the solid content was 77.4% by mass and powder. The concentration of gallic acid in the solid content was 0.2% by mass. When the aqueous solution (I) was cooled in the same manner as (A) by the method (2), the amount of crystals depended on the non-gallate fraction. It was found to increase (FIG. 1).

Example 2
(1) (Preparation of raw material aqueous solution)
The catechin aqueous solutions (C) and (D) of Example 1 are used.
(2) When the obtained aqueous solutions (C) and (D) (non-polymer catechin concentration in the aqueous solution of 15% by mass) were allowed to stand at room temperature of 25 ° C. for several hours, crystals were precipitated.
When the crystals were collected and analyzed, the non-gallate form of non-polymer catechins was almost 100% by mass in the composition of non-polymer catechins. (Figure 2)

Example 3
(1) (Preparation of raw material aqueous solution)
The catechin aqueous solution (A) to (I) of Example 1 is used.
(2) When the obtained aqueous solutions (C) and (D) (non-polymer catechin concentration in the aqueous solution of 15% by mass) were allowed to stand at room temperature for 25 hours, crystals were precipitated.
When the crystals were collected and analyzed, the non-gallate form of non-polymer catechins was almost 100% by mass in the composition of non-polymer catechins. (Figure 2)

Example 4
(1) (Preparation of raw material aqueous solution)
The catechin aqueous solution (A) to (I) of Example 1 is used.
(2) When the obtained aqueous solutions (C), (D) and (E) (non-polymer catechin concentration in the aqueous solution of 15% by mass) were allowed to stand at 5 ° C. for 3 days, crystals were precipitated.
When the crystals were collected and analyzed, the non-gallate form of non-polymer catechins was almost 100% by mass in the composition of non-polymer catechins. (Figure 3)

Example 5
The results when the catechin aqueous solution with a non-epimer ratio of 15 to 100% by mass and the aqueous solution with a non-epimer ratio of less than 15% by mass are used as raw materials (the operation is the same as in Example 1) are shown. 1 and Table 2.

  As is clear from Tables 1 and 2, when the non-epimer content of the raw material is 15 to 100% by mass, a non-gallate body having a non-epimer content of 20 to 100% by mass is selectively obtained. I understand. On the other hand, when the non-epimer content of the raw material is less than 15% by mass, it can be seen that a non-gallate body having a non-epimer content of 0 to 20% by mass is selectively obtained.

It is a figure which shows the relationship between the gallate body rate in raw material aqueous solution, and the amount of crystals. It is a figure which shows the relationship between the gallate body rate in raw material aqueous solution, and the amount of crystals. It is a figure which shows the relationship between the gallate body rate in raw material aqueous solution, and the amount of crystals.

Claims (6)

  Non-polymer catechins low gallate crystals characterized by cooling an aqueous solution containing 40 to 90 mass% of non-polymer catechins containing gallate bodies to 10 ° C. or less and recovering the precipitated crystals Manufacturing method.   The production method according to claim 1, wherein the crystal recovery method is selected from centrifugation, filtration, and decantation.   The production method according to claim 1 or 2, wherein the non-gallate content in the non-polymer catechins in the obtained solid content is 60 to 100% by mass.   Non-polymer catechins having a non-epimer content of 15 to 100% by mass in the non-polymer catechins as raw materials, and non-polymer catechins low gallate having a non-epimer content of 20 to 100% by mass The process according to any one of claims 1 to 3, wherein:   A non-polymer catechin having a non-epimer content of less than 15% by mass in the non-polymer catechins as a raw material, and a non-polymer catechins low gallate having a non-epimer content of 0 to 20% by mass The method according to any one of claims 1 to 3, which is obtained.   The method according to any one of claims 1 to 3, wherein a non-polymer catechin containing a gallate body is subjected to tannase treatment, and then the obtained non-polymer catechin is purified.

Images