JP2011182696A - Method for producing purified tea extract - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently and economically producing a purified tea extract useful as a raw material for drinks containing catechins which give good aftertastes, when held in a mouth, and can easily be drunk. <P>SOLUTION: The method for producing the purified tea extract comprises the first ultrafiltration process for passing a tea extract having a non-polymerized catechins concentration of ≥50 mass% in solid contents through the first ultrafiltration membrane, and the second ultrafiltration process for passing the filtrate obtained in the first ultrafiltration process through the second ultrafiltration membrane giving smaller fractionated molecular weight than those of the first ultrafiltration membrane. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a purified tea extract.

  Tea drinks are usually manufactured by blending tea extract obtained from tea, but the flavor balance is lost due to the catechin concentration in the tea extract to be blended, or aggregation of tea components in the tea extract, etc. Turbidity may occur and the value of the product may be impaired.

  Conventionally, as a method for improving the turbidity of a tea beverage, for example, methods for removing a water-insoluble component by ultrafiltration of a tea extract have been proposed (Patent Documents 1 to 5). In these conventional techniques, ultrafiltration is performed for the purpose of clarifying the tea extract (Patent Documents 1 to 5), but there is no report on the flavor improvement of the tea extract by ultrafiltration.

JP 63-36745 A JP-A-4-45744 JP 2006-197934 A JP 2001-197863 A JP 2009-60823 A

In recent years, demand for tea beverages has increased due to diversification of consumer preferences and health-conscious enhancement, and there is a need for catechin-containing beverages that have a refreshing aftertaste and are easy to drink and can be continuously consumed.
Accordingly, an object of the present invention is to provide an efficient and economical production of a purified tea extract useful as a raw material for a refreshing and easy-to-drink catechins-containing beverage that has no aftertaste when contained in the mouth. It is to provide a method.

  Therefore, the present inventors have made various studies in order to develop a refreshing and easy-to-drink catechin-containing beverage that has no aftertaste when contained in the mouth, and found a tea extract having specific properties. The two types of ultrafiltration membranes with different fractionation molecular weights are ultrafiltered in order from the ultrafiltration membranes with the highest fractionation molecular weights. Ingredients can be efficiently removed without greatly changing the composition of the tea extract, and as a result, the aftertaste when contained in the mouth is a refreshing and easy-to-drink catechin-containing beverage. It has been found that a purified tea extract useful as a raw material can be produced efficiently and economically.

That is, the present invention includes a first ultrafiltration step in which a tea extract having a non-polymer catechin concentration in a solid content of 50% by mass or more is passed through a first ultrafiltration membrane;
A purified tea comprising a second ultrafiltration step in which the filtrate obtained by the first ultrafiltration step is passed through a second ultrafiltration membrane having a fractional molecular weight lower than that of the first ultrafiltration membrane. A method for producing an extract is provided.

  According to the present invention, the taste ingredient contained in the tea extract is efficiently removed without greatly changing the composition of the tea extract, and the aftertaste when it is contained in the mouth has no taste and is refreshing. Thus, a purified tea extract useful as a raw material for a catechin-containing beverage that is easy to drink can be produced efficiently and economically. Therefore, the production method of the present invention can significantly reduce the labor (such as time) and cost required for production, and is therefore effective for producing a purified tea extract on an industrial scale. Moreover, since the purified tea extract obtained by the production method of the present invention can be taken easily and can be continuously ingested, the physiological effect of non-polymer catechins can be sufficiently expected.

First, terms used in this specification will be described.
In the present specification, the “aftertaste” refers to “feel remaining in the mouth” described in JIS Z 8144: 2004.
"(A) Non-polymer catechins" refers to non-epimeric catechins such as catechin, gallocatechin, catechin gallate, and gallocatechin gallate, and epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate. The catechins are a collective term, and the concentration of the non-polymer catechins is defined based on the total amount of the above eight types.
“(C) Galate form of non-polymer catechins” is a general term for catechin gallate, gallocatechin gallate, epicatechin gallate and epigallocatechin gallate. In addition, “(A) ratio of gallate body of (C) non-polymer catechins in non-polymer catechins” (hereinafter, also referred to as “(C) gallate body ratio”) means non-heavy weight in solid content. It is a mass ratio of the four gallate bodies to the total mass of the eight coalescent catechins.
“Solid content” refers to the mass of a residue obtained by drying a sample for 3 hours in an electric constant temperature dryer at 105 ° C. to remove volatile substances.

Hereinafter, the manufacturing method of the refined tea extract of this invention is demonstrated.
The method for producing a purified tea extract of the present invention is characterized by subjecting a tea extract having specific properties to a process including a first ultrafiltration step and a second ultrafiltration step. Hereinafter, each step will be described in detail.

(First ultrafiltration step)
The first ultrafiltration step is a step of allowing a tea extract having specific properties to pass through the first ultrafiltration membrane.
First, prior to ultrafiltration, a tea extract to be used in this step is prepared.
The tea extract used in this step has a (A) non-polymer catechin concentration in the solid content of 50% by mass or more, but from the viewpoint of improving aftertaste, 55% by mass or more, and further 60% by mass. As mentioned above, it is more preferable that it is 65 mass% or more, especially 70 mass% or more. In addition, although the upper limit of (A) non-polymer catechins concentration in solid content is not particularly limited, it is 95% by mass, further 90% by mass, further 85% by mass, particularly 80% by mass from the viewpoint of supplying raw materials. Is preferred.

The tea extract having such properties is at least one selected from a tea extract or a concentrate thereof (hereinafter also referred to as “tea extract etc.”) among the following (i) to (iii): It can be obtained by processing either or a combination of two or more.
(I) A method of bringing a tea extract or the like into contact with at least one adsorbent selected from activated carbon, acidic clay and activated clay in a mixed solution of organic solvent / water = 90/10 to 97/3 (for example, JP, 2007-282568, A).
(Ii) A method in which a tea extract or the like is adsorbed on a synthetic adsorbent and then an organic solvent aqueous solution is brought into contact with the synthetic adsorbent to desorb non-polymer catechins (for example, JP-A-2006-160656) .
(Iii) After the tea extract or the like is adsorbed on the synthetic adsorbent, an organic solvent aqueous solution or a basic aqueous solution (for example, sodium hydroxide aqueous solution) is brought into contact with the synthetic adsorbent to desorb non-polymer catechins. Then, a method of bringing the obtained detachment solution into contact with activated carbon (for example, JP 2008-079609).

  In the present invention, the tea extract before treatment or the tea extract after treatment may be treated with an enzyme having tannase activity. Thereby, the bitterness derived from non-polymer catechins can be reduced. In addition, the tannase process can employ | adopt the method as described in Unexamined-Japanese-Patent No. 2004-321105, for example.

Here, the “tea extract” refers to an extract extracted from tea tree using hot water or a water-soluble organic solvent, which has not been concentrated or purified. As the water-soluble organic solvent, for example, an alcohol such as ethanol or an organic solvent such as ethyl acetate can be used. As the extraction method, known methods such as kneader extraction, stirring extraction (batch extraction), countercurrent extraction (drip extraction), and column extraction can be employed.
The tea tree used for extraction can be divided roughly into non-fermented tea, semi-fermented tea, and fermented tea according to the processing method. Examples of non-fermented tea include green tea such as sencha, bancha, gyokuro, mochi tea, kettle tea, stem tea, stick tea, and bud tea. Examples of the semi-fermented tea include oolong tea such as iron kannon, color type, golden katsura, and martial arts tea. Furthermore, examples of fermented tea include black teas such as Darjeeling, Assam, Sri Lanka and the like. These can be used alone or in combination of two or more. Among these, green tea is preferable from the viewpoint of the content of non-polymer catechins.

  The “tea extract concentrate” is a part of the solvent extracted from the tea tree selected from non-fermented tea, semi-fermented tea and fermented tea with hot water or water-soluble organic solvent. Thus, the concentration of non-polymer catechins is increased. For example, JP-A-59-219384, JP-A-4-20589, JP-A-5-260907, JP-A-5-306279, etc. It can be prepared by the method described in 1. Examples of the form include various forms such as solid, aqueous solution, and slurry. Commercially available products may be used as the concentrate of the tea extract, such as “Polyphenone” from Mitsui Norin Co., “Theafranc” from ITO EN, “Sunphenon” from Taiyo Kagaku Co., Ltd. There is a liquid concentrate.

  In addition, the tea extract used in this step has a mass ratio of (A) non-polymer catechins and (B) caffeine [(B) / (A)] of 0.05 from the viewpoint of improving aftertaste. Hereinafter, it is further preferably 0.03 or less, particularly preferably 0.01 or less. In addition, the tea extract used at this process does not need to contain caffeine substantially, and mass ratio [(B) / (A)] may be 0. Here, in this specification, the measurement of each concentration of (A) non-polymer catechins and (B) caffeine is in accordance with “Measurement of non-polymer catechins and caffeine” described in Examples below. Shall. Further, “substantially does not contain caffeine” means that the amount of caffeine is below the detection limit in “Measurement of caffeine” in the examples described later.

  Furthermore, the tea extract used in this step has a (C) gallate content in the solid content of the tea extract of 10 to 60% by mass, more preferably 15 to 50% by mass, particularly 20 to 40%, from the viewpoint of improving the aftertaste. It is preferable that it is mass%.

After preparing the tea extract, the tea extract is subjected to a first ultrafiltration step.
The concentration of the non-polymer catechins in the tea extract when subjected to the first ultrafiltration is 0.5 to 15% by mass from the viewpoint of improving the yield of the non-polymer catechins and the production efficiency. It is preferable that it is 8-10 mass%, especially 1-7 mass%. In order to adjust the non-polymer catechins concentration in the tea extract within the above range, the tea extract may be concentrated or diluted as necessary.
As conditions for ultrafiltration, from the viewpoint of improving aftertaste and suppressing composition change of the tea extract, the temperature is preferably 0 to 40 ° C, more preferably 3 to 35 ° C, and particularly preferably 5 to 30 ° C.

Examples of the ultrafiltration membrane (UF membrane) used in this step include polysulfone-based, cellulose-based, polyacrylonitrile-based, polyimide-based or polyfluorinated hydrocarbon-based polymer membranes; ceramic-based membranes. Examples of the polysulfone polymer membrane include polysulfone, polyethersulfone, polyphenylsulfone, and polyarylsulfone. An example of the polyfluorinated hydrocarbon polymer film is polyvinylidene fluoride. Furthermore, examples of the cellulose polymer film include cellulose acetate, nitrocellulose, and regenerated cellulose. Examples of the ceramic film include MW5000cut manufactured by MEMBLAROX.
Among these, from the viewpoint of suppressing composition change of tea extract and production efficiency, polysulfone-based, cellulose-based, and polyacrylonitrile-based polymer membranes are preferable, and polysulfone-based polymer membranes are particularly preferable.

  Examples of the structure of the UF membrane include a flat membrane, a spiral membrane, and a hollow fiber membrane. Among these, a spiral membrane and a hollow fiber membrane are preferable from the viewpoint of production efficiency.

  The lower limit of the molecular weight of the UF membrane is preferably 5000, particularly 5500 from the viewpoint of improving aftertaste and suppressing the composition change of the tea extract, while the upper limit is 10,000, more 9000, more 8000, especially 7000. Is preferred.

  As such a UF membrane, for example, commercially available products such as Microza SIP-0013 (polysulfone membrane, manufactured by Asahi Kasei Chemicals), Amicon Ultra-15 Ultracel 10K (regenerated cellulose, manufactured by MILLIPORE) can be used.

Moreover, as a filtration system, crossflow filtration, centrifugal filtration, etc. are illustrated, for example, and crossflow filtration is especially preferable.
When the filtration method is cross flow filtration, the pressure is not particularly limited as long as it is within the pressure resistance range of the membrane module to be used. For example, 0.03 to 0.5 MPa, and further 0.05 to 0.3 MPa. Particularly preferred is 0.07 to 0.3 MPa. In particular, the pressure is preferably 0.1 to 0.2 MPa. The average transmission speed is preferably 0.3 to 10 g / min, more preferably 0.5 to 8 g / min, and particularly preferably 0.8 to 6.5 g / min.
On the other hand, when the filtration method is centrifugal filtration, the conditions can be appropriately set depending on the type of the centrifugal separator such as a separator plate type, a cylindrical type, and a decanter type. For example, in the case of the separator plate type, 3000 to 10,000 rpm / It is preferable that it is min, 3500-8000 rpm / min, especially 4000-6000 rpm / min, 1-120 minutes, Furthermore 20-100 minutes, Especially 40-80 minutes.

(Second ultrafiltration step)
The second ultrafiltration step is a step of allowing the filtrate obtained by the first ultrafiltration step to pass through the second ultrafiltration membrane having a fractional molecular weight lower than that of the first ultrafiltration membrane. . Thereby, the taste component contained in a tea extract can be reduced further, suppressing the composition change of a tea extract.
In this step, the filtrate obtained by the first ultrafiltration step can be directly used for the second ultrafiltration.

The molecular weight cutoff of the UF membrane used in this step is preferably 1500, more preferably 2000, especially 2500 from the viewpoint of improving aftertaste and suppressing the composition change of the tea extract, while the upper limit is less than 5000, and further 4500. Further, it is preferably 4000, particularly 3500.
In addition, about the kind and structure of a 2nd UF film | membrane used at this process, the thing similar to a 1st UF film | membrane is illustrated. As such a UF membrane, for example, commercially available products such as Microsa SEP-0013, Microsa SAP-0013 (polysulfone membrane, manufactured by Asahi Kasei Chemicals) can be used.

  Moreover, as conditions for the ultrafiltration in this step, the same conditions as those in the first ultrafiltration step can be employed.

  In this way, the taste component can be efficiently removed without greatly changing the composition of the tea extract used as the raw material. As a result, it is possible to efficiently and economically produce a purified tea extract useful as a raw material for a catechins-containing beverage that has a clean aftertaste when contained in the mouth and is easy to drink.

The obtained purified tea extract can have the following characteristics (1) to (6).
(1) The (C) gallate fraction in the solid content of the purified tea extract is usually 10 to 60% by mass, but the lower limit is 15% by mass, particularly 20% by mass from the viewpoint of suppressing the bitterness of the aftertaste. The other upper limit is preferably 50% by mass, more preferably 45% by mass, and particularly preferably 40% by mass.
(2) The mass ratio of (B) caffeine and (A) non-polymer catechins [(B) / (A)] has an upper limit of 0 from the standpoint of aftertaste bitterness and savory suppression, and from an economic viewpoint. 0.02, more preferably 0.01, especially 0.005, while the lower limit is preferably 0, more preferably 0.001, especially 0.002.
(3) (A) The lower limit of the L color value of the Lab color system of the aqueous solution when the non-polymer catechin concentration is adjusted to 0.175 g / 100 mL is 96, 97, In particular, 98 is preferable, and the other upper limit is not particularly limited.
(4) (A) The upper limit of the a value of the Lab color system of the aqueous solution when the non-polymer catechin concentration is adjusted to 0.175 g / 100 mL is −0.4, from the viewpoint of improving the appearance. Further, it is preferably -0.35, particularly -0.3, and the lower limit is preferably -0.01 from the economical viewpoint.
(5) (A) The upper limit of the b value of the Lab color system of the aqueous solution when the concentration of the non-polymer catechins is adjusted to 0.175 g / 100 mL is 5, further 3, from the viewpoint of improving the appearance. In particular, 2 is preferable, and the other lower limit is preferably 0.01 from the economical viewpoint.
(6) (A) The ab value of the Lab color system of the aqueous solution when the concentration of non-polymer catechins is adjusted to 0.175 g / 100 mL is -2, more preferably -1, from the viewpoint of improving the appearance. In particular, −0.5 is preferable, and the other lower limit is preferably −0.0001 from the economical viewpoint.
Here, “hue according to the Lab color system” means that measured by the method described in Examples below.

  Moreover, the obtained purified tea extract may be used as it is, or may be concentrated by concentration or drying. Examples of the concentration increasing method include vacuum concentration, reverse osmosis membrane concentration, spray drying, and freeze drying. Thereby, a refined tea extract can be made into forms, such as a powder and a granulated material.

  The refined green tea extract of the present invention has a suppressed aftertaste when contained in the mouth and is excellent in hue, so that it can be used in a wide range of applications. For example, the purified green tea extract of the present invention can be used as a raw material for foods and drinks, with beverages being particularly preferred.

  The content of the purified tea extract in the food and drink can be appropriately selected depending on the type, but for example, 0.1 to 20% by mass, particularly 0.1 to 10% by mass as non-polymer catechins. It is preferable to contain.

The beverage of the present invention may be a tea beverage or a non-tea beverage. Examples of tea beverages include green tea beverages, oolong tea beverages, and black tea beverages. Non-tea beverages include, for example, non-alcoholic beverages such as fruit juice, vegetable juice, sports beverage, isotonic beverage, enhanced water, bottled water, near water, coffee beverage, nutritional drink, beauty drink, beer Examples include alcoholic beverages such as wine, sake, plum wine, happoshu, whiskey, brandy, shochu, rum, gin, and liqueurs.
Examples of the food include confectionery (for example, baked confectionery such as bread, cake, cookies, biscuits, chewing gum, chocolate, candy), dessert (for example, jelly, yogurt, ice cream), retort food, seasoning (for example, , Sauce, soup, dressing, mayonnaise, cream). In addition, the form of food / beverage products is not specifically limited, As long as it is a form which is easy to ingest, any of solid, powder, liquid, gel form, slurry form, etc. may be sufficient.

  The beverages of the present invention include antioxidants, fragrances, organic acids, organic acid salts, inorganic acids, inorganic acid salts, inorganic salts, pigments, emulsifiers, preservatives, seasonings, sweeteners, acidulants, gums, oils. Additives such as vitamins, amino acids, fruit juice extracts, vegetable extracts, nectar extracts, pH adjusters, quality stabilizers and the like may be used alone or in combination.

  The pH (25 ° C.) of the beverage of the present invention is preferably 2 to 7, and preferably 2 to 6.5 in terms of taste and stability of non-polymer catechins.

In addition, the beverage of the present invention is a container packed in a normal packaging container such as a molded container mainly composed of polyethylene terephthalate (so-called PET bottle), a metal can, a paper container combined with a metal foil or a plastic film, or a bottle. Can be provided as a beverage.
In addition, packaged beverages are manufactured under the sterilization conditions stipulated in the applicable regulations (Food Sanitation Law in Japan) if they can be sterilized by heating after filling in containers such as metal cans. it can. For PET bottles and paper containers that cannot be sterilized by retort, sterilize under the same conditions as above, for example, after sterilizing at high temperature and short time with a plate heat exchanger, etc. The method can be adopted. Moreover, you may mix | blend another component with the filled container under aseptic conditions.

1. Measurement of non-polymer catechins and caffeine A sample solution is filtered through a filter (0.45 μm), and a high-performance liquid chromatograph (model SCL-10AVP, manufactured by Shimadzu Corporation) is used to form a packed column for an octadecyl group-introduced liquid chromatograph ( L-column TM ODS, 4.6 mmφ × 250 mm (manufactured by Chemical Substance Evaluation Research Organization) was attached, and analysis was performed at a column temperature of 35 ° C. by a gradient method. 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. . The gradient conditions are as follows.

Time (minutes) Liquid A concentration (volume%) Liquid B concentration (volume%)
0.0 97 3
5.0 97 3
37.0 80 20
43.0 80 20
43.5 0 100
48.5 0 100
49.0 97 3
60.0 97 3

2. Hue Measurement Each purified tea extract was diluted with ion-exchanged water so that the concentration of non-polymer catechins was 0.175 g / 100 mL, and a spectrophotometer (Model Color Meter ZE-2000, Nippon Denshoku Industries Co., Ltd.) )), And spectral sensitivity: XYZ method. The sample was put in a quartz cell having an optical path length of 10 mm, and L, a and b values of the Lab color system were measured at 20 ° C.

3. Measurement of Solid Content The sample was dried for 3 hours with an electric constant temperature dryer at 105 ° C., and the mass of the residue was measured.

4). Sensory evaluation Each purified green tea extract was diluted with ion-exchanged water so that the non-polymer catechin concentration would be 0.175 g / 100 mL to prepare a beverage. Next, a predetermined amount was scooped with a spoon, and a drinking test was conducted by four panelists on the taste when contained in the mouth. In the drinking test, the “green tea extract a” obtained in the following Production Example 1 was diluted with ion-exchanged water so that the non-polymer catechin concentration was 0.175 g / 100 mL, and this was used as a reference beverage. As a relative evaluation with respect to the beverage (score 3), the following 6 levels were evaluated. After that, the final score was determined in 0.5 increments by consultation.

(Evaluation criteria for aftertaste)
Score 5: The aftertaste has no taste and is very refreshing and good compared to the reference beverage.
Score 4: The aftertaste is less abundant than the standard beverage, and it is refreshing and better.
Rating 3: Standard Rating 2: Eg taste is slightly felt in the aftertaste compared to the standard beverage, and it is somewhat poor.
Score 1: The taste of the aftertaste is very felt and poor.

Production Example 1
Production of Green Tea Extract a Green tea leaves (large leaf seeds) were extracted with hot water at a bath ratio of 20: 1, and then water-insoluble matter was filtered through a 100 mesh wire net to obtain a green tea extract. Next, tannase (manufactured by Kikkoman Corporation, tannase KTFH, 500 U / g) was added at a concentration of 430 ppm with respect to the green tea extract. Next, after reacting at 25 ° C. for 60 minutes, the enzyme was deactivated by heating to obtain a green tea extract after tannase treatment. This tannase-treated green tea extract has (A) a non-polymer catechin concentration of 30.0% by mass, (B) a caffeine concentration of 4.8% by mass, (A) a non-polymer catechin and (B ) The mass ratio [(B) / (A)] to caffeine was 0.16, and (C) the gallate body fraction was 35.0% by mass.
Into a synthetic adsorbent (SP-70, manufactured by Mitsubishi Chemical Corporation) 600 mL (40 g / L based on the mass of non-polymer catechins) packed in a cylindrical column, 2400 g of green tea extract after tannase treatment was added to SV. The liquid was passed under the condition of = 1 (h ⁻¹ ) to adsorb non-polymer catechins. Next, the synthetic adsorbent was washed by passing 900 g of pure water under the condition of SV = 1 (h ⁻¹ ). Next, in order to desorb non-polymer catechins, 750 g of a 30% by mass ethanol aqueous solution was passed under conditions of SV = 1 (h ⁻¹ ) to obtain a desorbed solution. Next, the column was packed with granular activated carbon (Taiko SGP, manufactured by Phutamura Chemical Co., Ltd.) in an amount of 30% by mass with respect to the non-polymer catechins in the desorbed liquid. Next, the effluent was passed through the column to recover the treatment liquid, and ethanol was distilled off to obtain “green tea extract a”.
The “green tea extract a” has a (A) non-polymer catechin concentration of 4% by mass, a (A) non-polymer catechin concentration in solids of 76.6% by mass, and (B) a caffeine concentration of 0. 0.004 mass%, the mass ratio [(B) / (A)] was 0.001, and (C) the gallate fraction was 28.7 mass%.

Production Example 2
Manufacture of green tea extract b 200 g of concentrated green tea extract (polyphenone HG, manufactured by Mitsui Norin Co., Ltd.) was dispersed in 800 g of 95% by weight ethanol aqueous solution under stirring conditions at 250 ° C. at 25 ° C. After introducing 100 g (Mizuka Ace # 600, manufactured by Mizusawa Chemical Co., Ltd.), stirring was continued for about 10 minutes. Next, after filtering with No. 2 filter paper, 16 g of activated carbon was added to the filtrate and filtered again with No. 2 filter paper. Next, it was re-filtered through a 0.2 μm membrane filter. Next, ethanol was distilled off from the filtrate under reduced pressure at 40 ° C., and the concentration of non-polymer catechins was adjusted with ion-exchanged water to obtain “green tea extract b”.
“Green tea extract b” has a concentration of (A) non-polymer catechins of 14.8% by mass, (A) concentration of non-polymer catechins in the solid content of 62.7% by mass, and (B) caffeine concentration. 0.34% by mass, (A) non-polymer catechins and (B) caffeine mass ratio [(B) / (A)] is 0.023, and (C) gallate body ratio is 45.9 masses. %Met.

Production Example 3
Manufacture of green tea extract c 200 g of a concentrated green tea extract (polyphenone HG, manufactured by Mitsui Norin Co., Ltd.) was dispersed in 800 g of a 40% by mass ethanol aqueous solution under a stirring condition of 250 r / min at 25 ° C. After introducing 80 g (Mizuka Ace # 600, manufactured by Mizusawa Chemical Co., Ltd.), stirring was continued for about 10 minutes. Next, after filtering with No. 2 filter paper, 8 g of activated carbon was added to the filtrate and filtered again with No. 2 filter paper. Next, it was re-filtered through a 0.2 μm membrane filter. Next, ethanol was distilled off from the filtrate at 40 ° C. under reduced pressure, and the concentration of non-polymer catechins was adjusted with ion-exchanged water to obtain “green tea extract c”.
“Green tea extract c” has (A) a non-polymer catechin concentration of 22.4% by mass, (A) a non-polymer catechin concentration in the solid content of 43.2, and (B) a caffeine concentration of 1. 0.1 mass%, (A) non-polymer catechins and (B) caffeine mass ratio [(B) / (A)] is 0.049, (C) gallate body ratio is 50.1 mass% there were.

Example 1
“Green tea extract a” was diluted with ion-exchanged water so that the Brix value was 10 (non-polymer catechin concentration: 5.0 mass%). Next, it was circulated at a circulation flow rate of 0.95 L / min at 5 ° C. in a filtration apparatus [FILTRATION SYSTM PS-24001, manufactured by Asahi Kasei Co., Ltd.] equipped with a UF membrane shown in Table 1. A first ultrafiltration step was performed by a filtration method. The circulation flow rate was measured with a flow meter [Model NW05-TTN, manufactured by Aichi Watch Electric Co., Ltd.].
Next, the obtained filtrate is subjected to a second ultrafiltration step under the same conditions as the first ultrafiltration step on the above filtration device equipped with the UF membrane shown in Table 1, and a purified green tea extract is obtained. Got. Table 1 shows the physical properties and sensory evaluation results of the obtained purified green tea extract.

Example 2
A purified green tea extract was obtained in the same manner as in Example 1 except that “green tea extract b” was used instead of “green tea extract a” and the temperature was changed to 25 ° C. Table 1 shows the physical properties and sensory evaluation results of the obtained purified green tea extract.

Comparative Example 1
“Green tea extract a” was used as it was without ultrafiltration. Table 1 shows the physical properties and sensory evaluation results of the green tea extract a.

Comparative Example 2
A purified green tea extraction was obtained by the same operation as in Example 1 except that only the first ultrafiltration step was performed without performing the second ultrafiltration step. Table 1 shows the physical properties and sensory evaluation results of the obtained purified green tea extract.

Comparative Example 3
In the second ultrafiltration step, purified green tea extraction was obtained by the same operation as in Example 1 except that the UF membrane shown in Table 1 was used. Table 1 shows the physical properties and sensory evaluation results of the obtained purified green tea extract.

Comparative Example 4
Extraction of purified green tea by the same operation as in Example 1 except that the first ultrafiltration step was performed at 25 ° C. using the UF membrane shown in Table 1 and the second ultrafiltration step was not performed. Although the product was manufactured, filtration became impossible due to clogging. Therefore, it was judged that filtration was impossible and production was stopped.

Comparative Example 5
Instead of “green tea extract a”, “green tea extract c” in which the non-polymer catechin concentration was diluted to 3.5% by mass was used, and the temperature was changed to 30 ° C., as in Example 1. A purified green tea extract was obtained by the above procedure. Table 1 shows the physical properties and sensory evaluation results of the obtained purified green tea extract.

  From Table 1, two types of ultrafiltration membranes with different fractional molecular weights were combined, and the tea extract in which the concentration of non-polymer catechins in the solid content was controlled to be limited in order from the ultrafiltration membrane with the highest fractional molecular weight. By filtering outside, the components of the tea extract used as a raw material are efficiently removed without drastically changing the composition, and the aftertaste when it is contained in the mouth is clean and refreshing. It was confirmed that a purified tea extract capable of providing easy-to-use catechin-containing beverages can be produced efficiently and economically.

Claims (4)

A first ultrafiltration step of passing a tea extract having a non-polymer catechin concentration in a solid content of 50% by mass or more through a first ultrafiltration membrane;
A purified tea comprising a second ultrafiltration step in which the filtrate obtained by the first ultrafiltration step is passed through a second ultrafiltration membrane having a fractional molecular weight lower than that of the first ultrafiltration membrane. A method for producing an extract.   The production method according to claim 1, wherein the molecular weight cut-off of the first ultrafiltration membrane is 5000 or more and 10,000 or less.   The production method according to claim 1 or 2, wherein the molecular weight cut-off of the second ultrafiltration membrane is 1500 or more and less than 5000.   The manufacturing method of any one of Claims 1-3 whose tea extract is a green tea extract.