JP7362705B2 - Method for producing polyphenol-reduced beverages - Google Patents

Description

The present invention relates to a method for producing a beverage containing reduced polyphenols. The present invention also relates to a method of reducing polyphenol content in polyphenol-containing beverages.

In addition to antioxidant effects, polyphenols have hormone-like effects and interactions with proteins.
Because it has various biological functions, it is attracting attention as a functional food material. On the other hand, in the field of beverage manufacturing, polyphenols are also causative substances that cause problems related to beverage quality such as turbidity, precipitation, browning, and flavor stability. In particular, in the case of packaged beverages, it is required to produce products with stable quality that do not cause turbidity or precipitation even after long-term storage.

It is known that polyphenols interact with various substances and functional groups due to their structure, and various techniques have been disclosed so far regarding methods for reducing and removing polyphenols using this property. As a typical technique, a technique is known in which polyvinylpolypyrrolidone (PVPP) is added to a polyphenol-containing beverage to reduce and remove polyphenols using PVPP (see, for example, Patent Documents 1 and 2).

However, since PVPP is an insoluble powder and has swelling properties, it is not easy to handle, and in polyphenol reduction/removal technology using PVPP, PVPP is added to polyphenol-containing beverages to maintain a constant level. It was necessary to remove the PVPP that had adsorbed polyphenols from the beverage by contacting it for a period of time. For this reason, the method of reducing and removing polyphenols using PVPP complicates the manufacturing process, and the manufacturing efficiency cannot necessarily be said to be good. In addition, the above method requires special equipment such as a filtration device and a centrifugal separator to completely remove PVPP from beverages, and there is also the problem of increased costs because PVPP is not an inexpensive adsorbent. .

Japanese Unexamined Patent Publication No. 62-61569 Japanese Patent Application Publication No. 8-28235

An object of the present invention is to provide a method for producing a beverage with a reduced polyphenol content, which has excellent polyphenol removal efficiency and easy handling of an adsorption material, and a method for reducing the polyphenol content in a polyphenol-containing beverage. .

The present inventors recently discovered that when a graft-polymerized nylon fiber obtained by polymerizing various polymerizable monomers onto a nylon base material by radiation graft polymerization was brought into contact with a green tea extract, N-vinyl-2 - It has been found that a nylon fiber obtained by graft polymerization of pyrrolidone has an excellent catechin removal effect, and the fluctuation range of beverage pH after treatment is small. The present inventors also confirmed that the polyphenol removal effect by the graft polymerized nylon fibers was also exhibited in polyphenol-containing beverages other than green tea extract. The present invention is based on these findings.

According to the present invention, the following inventions are provided.
[1] A beverage with reduced polyphenol content, which is characterized by contacting a polyphenol-containing beverage or its raw material with a polymeric base material obtained by graft polymerization of a polymerizable monomer containing N-vinylalkylamide. Production method.
[2] The production method according to [1] above, wherein the N-vinylalkylamide is N-vinyl-2-pyrrolidone.
[3] The pH of the beverage or its raw materials after contact with the polymer base material is ± with respect to the pH before contact.
The manufacturing method according to [1] or [2] above, wherein the manufacturing method is within the range of 0.3.
[4] The manufacturing method according to any one of [1] to [3] above, wherein the polymer base material is a polymer base material that has been subjected to a recycling treatment.
[5] The regeneration treatment according to any one of [1] to [4] above, wherein the regeneration treatment is carried out by bringing the polyphenol-adsorbed polymer base material into contact with a neutral regenerant, an alkaline regenerant, or an acidic regenerant. manufacturing method.
[6] The polyphenol-containing beverage is green tea, black tea, oolong tea, blended tea, brewed liquor, distilled liquor, vegetable drink, fruit drink, fruit/vegetable mixed juice, coffee drink, grain milk, vinegar drink, or non-alcoholic beer-taste drink, or A combination of these [1]
] to [5] the manufacturing method according to any one of them.
[7] The manufacturing method according to any one of [1] to [6] above, which is a packaged beverage.
[8] A polyphenol-containing beverage or a raw material thereof, which is characterized by contacting a polyphenol-containing beverage or a raw material thereof with a polymer base material obtained by graft polymerization of a polymerizable monomer containing N-vinylalkylamide. How to reduce the amount.

According to the present invention, a beverage with a reduced polyphenol content and a high polyphenol removal rate can be produced by simply bringing a polyphenol-containing beverage or its raw material liquid into contact with a graft polymerized polymer base material. This polymeric base material can be processed into various shapes such as fibers, and there are no handling problems, and beverages with reduced polyphenol content can be easily produced.

FIG. 1 is a diagram showing the relationship between the addition rate (%) of graft polymerized fibers and the total catechin removal rate (%) when the green tea extract and the graft polymerized fibers are brought into contact. FIG. 2 is a diagram showing the relationship between the contact time (minutes) and the total catechin removal rate (%) when the green tea extract and the graft polymerized fibers are brought into contact. FIG. 3 is a diagram showing the relationship between the contact temperature (° C.) and the total catechin removal rate (%) when the green tea extract and the graft polymerized fiber are brought into contact. FIG. 4 is a diagram showing the relationship between regeneration treatment conditions and adsorption regeneration rate (%) when a green tea extract and a graft polymerized fiber are brought into contact.

Specific description of the invention

The production method of the present invention can be used to reduce the polyphenol content in polyphenol-containing beverages. The applicable beverages are not particularly limited as long as they contain polyphenols.

Here, "polyphenol" is a general term for compounds having multiple phenolic hydroxyl groups in the molecule. Polyphenols are broadly divided into monomeric polyphenols (e.g., anthocyanins, isoflavones, catechins (e.g., epigallocatechin, epicatechin gallate, epigallocatechin gallate, catechin, gallocatechin, catechin gallate, gallocatechin gallate), etc. flavonoids, phenylpropanoids typified by caffeic acid, chlorogenic acid, sesamin, etc.) and polymeric polyphenols, which are made by polymerizing monomeric polyphenols.The latter polymers include proanthocyanidins (especially , condensed tannins such as procyanidins (procyanidins formed by polymerization of catechins), and hydrolyzed tannins such as gallotannins.

Polyphenols are found in plant parts such as leaves, stems, fruits, pericarp, seeds, and roots, and polyphenol-containing beverages are typically found in tea leaves, malt, hops, grains, vegetables, fruits, coffee, and cacao. It is a beverage manufactured using plant materials such as. In the present invention, examples of "polyphenol-containing beverages" include tea beverages (e.g., green tea, black tea, oolong tea, blended tea), brewed liquors (e.g., malt fermented beverages such as beer and low-malt beer, Japanese sake, and fruits such as wine and cider). liqueurs such as sake and plum wine), distilled spirits (e.g. whisky, shochu, brandy), vegetable drinks (e.g. tomato juice, carrot juice, tomato mixed juice,
mixed carrot juice), fruit drinks (e.g. apple juice, orange juice,
fruit juice drinks), mixed fruit/vegetable juices, coffee drinks, cereal milks (e.g. soy milk,
rice milk, coconut milk, almond milk), vinegar drinks (e.g. fruit vinegar drinks)
and non-alcoholic beer-taste drinks. Further, the polyphenol-containing beverage provided by the present invention may be a combination of two or more of the above beverages, for example,
Examples include combinations of tea drinks such as lemon tea and fruit drinks.

The measurement of the polyphenol content in a polyphenol-containing beverage can be determined depending on the nature of the beverage and the type of polyphenol contained in the beverage. For example, in the case of tea beverages, the amount of tannins can be used as the polyphenol content, and the polyphenol content can be measured using the iron tartrate method, which is a standard for evaluating the amount of polyphenols in tea. In addition, for fermented malt beverages such as beer, the EBC method (EUROPEAN BREWERY CONVENTION.
Furthermore, the polyphenol content of fruit juice drinks and fruit wines such as wine and apple juice can be measured according to the Folin-Ciocalt method. Alternatively, individual specific components may be measured using high performance liquid chromatography (HPLC) as described in the Examples below.

In the production method of the present invention, a polymer base material (hereinafter sometimes referred to as "polymer base material of the present invention") obtained by graft polymerizing a polymerizable monomer containing N-vinylalkylamide is used as a polyphenol adsorption material. It is characterized by using

In the present invention, graft polymerization is preferably carried out by a radiation graft polymerization method, that is, a method in which a base material is irradiated with radiation and a polymerizable monomer is polymerized onto the base material using radicals generated on the surface of the base material or inside the base material. can be carried out.

Ionizing radiation can be used as the radiation irradiated to the polymer base material, such as α rays, β rays, γ rays, electron beams, neutron beams, etc., but it can penetrate from the surface of the polymer base material to the deep part. γ-rays and electron beams are preferred. The radiation irradiation conditions are not particularly limited as long as a suitable functional group density is achieved, but it can be 5 to 200 kGy in a deoxidized state,
Preferably it is 30 to 100 kGy. Methods for deoxidizing the reaction system are known to those skilled in the art and can include, for example, bubbling an inert gas such as nitrogen into the reaction system.

When a polymer base material is irradiated with ionizing radiation, radicals are generated on the surface and inside of the polymer base material, and when the irradiated base material is brought into contact with a polymerizable monomer, the generated radicals are used as the starting point for the irradiation. A monomer can be polymerized onto the base material. Radiation graft polymerization is
For example, the polymer substrate can be immersed in a solution containing a diluted polymerizable monomer.

Here, the polymer base material is not particularly limited as long as it is a polymer base material on which a graft polymerization reaction can proceed and can be used for polyphenol reduction treatment, but examples include polyolefin resins (e.g., polyethylene, polypropylene), polyamide resins, etc. Includes resins (eg, nylon) and cellulose. In addition, the shape of the polymer base material can be fibrous, hollow fiber, nonwoven fabric, or bead-like from the viewpoint of efficiently performing polyphenol reduction treatment.

Furthermore, N-vinylalkylamide may be used as a polymerizable monomer to be subjected to a graft polymerization reaction with a polymeric base material. N-vinylalkylamide can be represented by the following formula (I).

R ¹ -C(=O)-N(-R ² )-CH=CH ₂ (I)
(In the above formula, R ¹ represents an alkyl group having 1 to 4 carbon atoms, and R ² is a hydrogen atom or
4 alkyl group, or R ¹ and R ² together represent an alkylene group having 3 to 5 carbon atoms. )

The "alkyl group having 1 to 4 carbon atoms" may be linear, branched, cyclic, or a combination thereof, such as methyl, ethyl, propyl, butyl, isopropyl,
Examples include isobutyl, tert-butyl, cyclopropyl, cyclobutyl, etc., preferably a linear alkyl group having 1 to 3 carbon atoms, and more preferably methyl.

Preferred embodiments of the compound of formula (I) include the following.
・Compound of formula (I) where R ¹ represents a methyl group and R ² represents a hydrogen atom (N-vinylacetamide)
- A compound of formula (I) in which R ¹ and R ² together represent an alkylene group having 3 carbon atoms (N-vinyl-2-pyrrolidone)
・A compound of formula (I) in which R ¹ and R ² together represent an alkylene group having 4 carbon atoms (N-vinylpiperidone)

The ratio of the graft-polymerized polymerizable monomer (functional group density) per unit mass of the polymer base material can be arbitrarily set depending on the polymerizable monomer and graft polymerization conditions.

The production method of the present invention is characterized by having a step of bringing a polyphenol-containing beverage or its raw material into contact with the polymer base material of the present invention. The contact step can be carried out by immersing the polymer base material of the present invention in a polyphenol-containing beverage or its raw material, but it may also be performed by immersing the polymer base material of the present invention in the form of a filter or filled with the polymer base material of the present invention. It can also be carried out by passing the polyphenol-containing beverage or its raw material through the column.

The contact time and contact temperature between the polyphenol-containing beverage or its raw material and the polymer base material of the present invention can be appropriately determined depending on the amount of polyphenol to be removed, with reference to Examples described later. As shown in the Examples below, the polyphenol removal ability of the polymer base material of the present invention does not decrease even when the liquid temperature is relatively high. can be brought into contact with the polymer base material of the present invention, and a tea beverage with reduced polyphenol content can be efficiently produced.

According to the production method of the present invention, a beverage with reduced polyphenol content can be produced. Here, "beverage with reduced polyphenol content" means a drink with reduced polyphenol content compared to a polyphenol-containing drink produced without contacting with the polymer base material of the present invention, For example, 90% or less (preferably 80% or less, more preferably 70% or less) of the polyphenol content of the beverage produced without contacting with the polymer base material of the present invention.
Beverages with a polyphenol content of

In the production method of the present invention, the p of the beverage or its raw material after contacting with the polymer base material of the present invention is
It has the characteristic that the fluctuation range of H can be kept small. Specifically, the pH of the beverage or its raw material after contact with the polymer base material of the present invention is within a range of ±0.3 (preferably within a range of ±0.2) relative to the pH before contact. can be achieved. If there is a large pH fluctuation in the contacting process, it is necessary to adjust the pH using a pH adjuster or the like in the subsequent process, and the flavor of the beverage may be affected by the pH adjuster. Since the range of pH fluctuation after contact with the polymer base material of the invention is small, there is almost no need to adjust the pH using a pH adjuster, and a beverage with excellent flavor can be produced. Here, the pH variation within the range of ±0.3 means, for example, that the pH of the beverage or its raw material before contacting with the polymer base material of the present invention is 5.88.
If it is, it means that the pH after contact is 5.58 to 6.18.

In the production method of the present invention, a polyphenol-containing beverage or its raw material is brought into contact with the polymer base material of the present invention, but whether it is brought into contact with the polyphenol-containing beverage or its raw material is determined by
It can be determined for each beverage by considering polyphenol removal rate, production efficiency, impact on flavor, etc. For example, when producing a tea beverage or a coffee beverage, a tea extract or a coffee extract can be brought into contact with the polymer base material of the present invention. The tea extract used in the present invention is not only a tea extract extracted from tea leaves, but also commercially available products such as Polyphenon (manufactured by Mitsui Norin Co., Ltd.), Sunphenon (manufactured by Taiyo Kagaku Co., Ltd.), and Theafuran (manufactured by Itoen Co., Ltd.). Tea extracts and powders may be used, and these extracts and powders may be dissolved in water or hot water. Furthermore, these concentrated tea extracts and purified tea extracts may be used alone, in combination of a plurality of types, or in combination with a tea extract.

In addition, when producing brewed liquors such as fermented malt drinks and fruit wines, the pre-fermentation liquid or the fermented liquid after brewing can be brought into contact with the polymer base material of the present invention. Preferably, the liquid is brought into contact with the polymeric substrate of the present invention. Furthermore, when producing fruit drinks or vegetable drinks, concentrated fruit juice or concentrated vegetable juice can be brought into contact with the polymer base material of the present invention.

The production method of the present invention can be carried out according to normal beverage production procedures, except for bringing the polyphenol-containing beverage or its raw material into contact with the polymer base material of the present invention.

For example, when producing tea drinks or coffee drinks, the tea extract or coffee extract that has been brought into contact with the polymeric base material of the present invention may be added to the tea extract or coffee extract that has been brought into contact with the polymer base material of the present invention. Tea beverages and coffee beverages can be produced by adding the following ingredients. The above ingredients include food additives such as sweeteners, acidulants, flavors, pigments, bittering agents, preservatives, antioxidants, thickening stabilizers, emulsifiers, dietary fibers, pH adjusters, enzymes, and fortifiers. Examples include, but are not limited to, agents.

In addition, when producing brewed liquors such as fermented malt beverages and fruit liquors, the fermented liquor that has been brought into contact with the polymer base material of the present invention may be added to the fermented liquor, if necessary, to be used in the production of ordinary brewed liquors. A brewed liquor can be produced by adding the following ingredients. The above ingredients include, for example:
Food additives such as sweeteners, acidulants, flavors, pigments, foaming/foam retention improvers, bittering agents, preservatives, antioxidants, thickening stabilizers, emulsifiers, dietary fibers, pH adjusters, enzymes, and fortifying agents. Agents can be mentioned, but
It is not limited to these.

The beverage with reduced polyphenol content produced by the present invention can be provided as a packaged beverage through processes such as a filling process and a sterilization process in addition to the above-mentioned blending process. For example, the blended liquid obtained in the above blending step can be sterilized according to a conventional method and then filled into containers. Sterilization may be performed before or after filling the container. The filling process and the sterilization process are well known in the art, and can be appropriately determined depending on the type of liquid.

The container used for the beverage produced according to the present invention may be any container commonly used for filling beverages, and can be appropriately selected depending on the type of liquid. Examples of containers include metal cans, barrel containers, plastic bottles (e.g., PET bottles, cups), paper containers, bottles, pouch containers, etc., but preferably metal cans/barrel containers, plastic bottles ( For example, P.E.
Examples include T-bottle) and bottles. Although packaged beverages have had the problem of turbidity, precipitation, etc. occurring even after long-term storage, the production method of the present invention is suitable for producing packaged beverages because polyphenols can be efficiently removed.

In the production method of the present invention, a polymer base material used for adsorbing polyphenols is subjected to a regeneration treatment to prepare a polymer base material whose polyphenol adsorption function has been regenerated, and the polymer base material subjected to the regeneration treatment is The material may again be used for adsorption of polyphenols. That is, the production method of the present invention may include the step of contacting the polymer base material after polyphenol adsorption with a regenerant, and then obtaining a polymer base material with regenerated polyphenol adsorption ability. Furthermore, the method may further include a step of recovering the polyphenol eluted from the polymer substrate after the polymer substrate after polyphenol adsorption is brought into contact with a regenerant. The regenerant that desorbs polyphenols from the used polymer base material may be any of a neutral regenerant, an alkaline regenerant, and an acidic regenerant, as long as it is acceptable in terms of food hygiene. Examples of neutral regenerants include ion-exchanged water, and examples of alkaline regenerants include one or more alkaline components such as sodium hydroxide, sodium silicate, sodium bicarbonate, and sodium carbonate. Examples of acidic regenerants include phosphoric acid, hydrochloric acid, nitric acid, sulfuric acid,
Examples include aqueous solutions containing one or more acids such as citric acid and hypochlorous acid as main components. As described above, the polymer base material used in the production method of the present invention is recyclable, so it can be used repeatedly and does not need to be disposed of, which is advantageous in that the production cost can be reduced.

The polymer base material used in the production method of the present invention can also be processed into various shapes such as fibers, so there are no handling problems and beverages with reduced polyphenol content can be easily produced. can. Further, since a maintenance step and a filtration step are not required in the contacting step with the polymer base material of the present invention, the step is simplified and production efficiency is improved. Furthermore, since the polymer base material of the present invention is in a solid state, it is advantageous in that there is no swelling problem.

According to another aspect of the present invention, a polyphenol-containing beverage or its raw material is brought into contact with a polymer base material obtained by graft polymerization of N-vinylalkylamide as a monomer. A method of reducing polyphenol content in a feedstock is provided. The polyphenol content reduction method of the present invention can be carried out according to the content described in the production method of the present invention.

Example 1: Addition rate and catechin removal characteristics in green tea (1) Preparation of green tea extract 400 g of hot water at 70° C. was added to 10 g of green tea leaves, and extracted for 10 minutes. After extraction, the mixture was passed through a mesh with an opening of 100 μm and rapidly cooled to 20° C. on ice to obtain a green tea extract.

(2) Graft-polymerized fibrous body treatment to green tea extract Graft-polymerized nylon fibrous body obtained by polymerizing N-vinyl-2-pyrrolidone onto a nylon base material by radiation graft polymerization (functional group density of about 4 mmol/g, (manufactured by Environmental Purification Research Institute) was added to the green tea extract at different addition rates, and after shaking and contacting at a predetermined temperature (20°C) for 2 hours, the graft polymerized fibers were removed to obtain a green tea treatment solution. .

(3) Measurement of total catechin concentration The green tea liquid obtained in (2) above was filtered through a membrane filter (DISMIC hydrophilic PTF).
E, 0.45 μm, manufactured by Advantech), and then subjected to high performance liquid chromatography (HPLC) under the HPLC analysis conditions shown in Table 1 to measure the total catechin concentration.

Total catechin here refers to the total of catechins, which are a type of polyphenol generally present in green tea, including epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECg), and epigallocatechin. Refers to the total of eight types: gallate (EGCg), catechin (C), gallocatechin (GC), catechin gallate (Cg), and gallocatechin gallate (GCg).

From the total catechin concentration of the green tea extract before and after the graft polymerization fiber treatment, the total amount of catechins adsorbed on the graft polymerization fiber was calculated as the total catechin removal rate. The total catechin concentration of the green tea extract before graft polymerization fiber treatment was 179.8 mg/100 ml.

(4) Results The addition rate of the nylon fiber graft-polymerized with N-vinyl-2-pyrrolidone, the total catechin concentration after treatment, and the total catechin removal rate are as shown in Table 2. Furthermore, the relationship between the addition rate (%) of the graft polymerized fibers and the total catechin removal rate (%) was as shown in FIG.

It was found that as the addition rate of graft polymerized fibers increased, the removal rate of total catechins increased.

Example 2: Contact time and catechin removal characteristics in green tea (1) Preparation of green tea extract A green tea extract was obtained in the same manner as in Example 1 (1).

(2) Treatment of graft polymerized fibers on green tea extract In the same manner as in Example 1 (2), N-vinyl-2 was applied to a nylon base material by radiation graft polymerization.
- Graft polymerized nylon fibers obtained by polymerizing pyrrolidone are added to the extract at a concentration of 2% by mass, and shaken with the green tea extract at a predetermined temperature (20°C) for various contact times. After this contact, the graft polymerized fibers were removed to obtain a green tea treatment liquid.

(3) Measurement of total catechin concentration As in (3) of Example 1, the total catechin concentration was measured and the total catechin removal rate was calculated. The total catechin concentration of the green tea extract before graft polymerization fiber treatment was 201.0 mg/100 mL.

(4) Results The contact time and total catechin removal rate of the nylon fiber graft-polymerized with N-vinyl-2-pyrrolidone were as shown in Table 3 and FIG. 2.

It was found that the longer the contact time of the graft polymerized fibers, the higher the total catechin removal rate.

Example 3: Contact temperature and catechin removal characteristics from green tea (1) Preparation of green tea extract A green tea extract was obtained in the same manner as in Example 1 (1).

(2) Treatment of graft polymerized fibers on green tea extract In the same manner as in Example 1 (2), N-vinyl-2 was applied to a nylon base material by radiation graft polymerization.
- Graft polymerized nylon fibers obtained by polymerizing pyrrolidone were added to the extract at a concentration of 2% by mass, and after contacting with shaking for 1 hour under various temperature conditions, the graft polymerized fibers were added. It was removed to obtain a green tea processing solution.

(3) Measurement of total catechin concentration As in (3) of Example 1, the total catechin concentration was measured and the total catechin removal rate was calculated. The total catechin concentration of the green tea extract before graft polymerization fiber treatment was 216.6 mg/100 ml.

(4) Results The contact temperature and total catechin removal rate of the nylon fiber graft-polymerized with N-vinyl-2-pyrrolidone were as shown in Table 4 and FIG. 3.

The higher the contact temperature of the graft polymerized fibers, the higher the total catechin removal rate;
It was found that the removal rate of total catechins did not decrease even at 0°C, and the contacting step could be carried out even at relatively high temperatures.

Example 4: Regeneration treatment conditions and polyphenol removal characteristics (1) Preparation of green tea extract A green tea extract was obtained in the same manner as in Example 1 (1).

(2) Treatment of graft polymerized fibers on green tea extract In the same manner as in Example 1 (2), N-vinyl-2 was applied to a nylon base material by radiation graft polymerization.
- Graft polymerized nylon fibers obtained by polymerizing pyrrolidone were added to the extract at a concentration of 2% by mass, and the mixture was brought into contact with the green tea extract at a predetermined temperature (20°C) for 1 hour with shaking,
The graft polymerized fibers were removed to obtain a green tea treatment liquid.

(3) Regeneration treatment The graft polymerized fibers brought into contact with the green tea extract in (2) above were regenerated by being washed for 5 minutes at various temperature conditions using various regeneration treatment solutions. Sodium hydroxide (NaOH
) or phosphoric acid as the regeneration treatment liquid, neutralization washing was further performed with ion-exchanged water at 20 to 25°C. The graft polymerized fibers after the regeneration treatment were brought into contact with the green tea extract before treatment again under the same conditions as in (2) above to obtain a green tea treatment liquid.

(4) Measurement of total catechin concentration Measure the total catechin concentration in the same manner as in (3) of Example 1, and calculate the adsorption regeneration rate from the first total catechin removal rate and the total catechin removal rate after regeneration treatment according to the following formula. Calculated. The total catechin concentration of the green tea extract before graft polymerization fiber treatment was 203.7 mg/100 ml.

(5) Results The relationship between the regeneration treatment conditions and adsorption regeneration rate of nylon fibers graft-polymerized with N-vinyl-2-pyrrolidone was as shown in Table 5 and FIG. 4.

It has been found that by regenerating the graft polymerized fiber using 2% NaOH, the polyphenol removal ability can be recovered to almost 100%. It was also found that the ability to remove polyphenols was greatly recovered even when relatively high temperature ion-exchanged water or phosphoric acid was used.

Example 5: Polyphenol removal characteristics for various beverages (1) Preparation of test beverage (a) Preparation of black tea extract 400 g of hot water at 90° C. was added to 10 g of black tea leaves, and extracted for 10 minutes. After extraction, the mixture was passed through a mesh with an opening of 100 μm and rapidly cooled to 20° C. on ice to obtain a black tea extract, which was used as a sample solution (Sample 5-1).

(B) Preparation of beer Warm water was added to the ground malt, hops were added to the wort obtained through the saccharification process and the filtration process, and the mixture was boiled.The resulting wort was then cooled and yeast was added. After alcoholic fermentation, a maturing period was allowed, and beer (malt usage ratio: 100%) was obtained, which was used as a sample solution (sample 5-2).

(c) Preparation of wine and fruit juice Commercially available red wine and apple juice (10°Brix) were used as sample solutions (Sample 5-3, Sample 5-4), respectively.

(2) Graft-polymerized fibrous treatment of test sample In the same manner as in Example 1 (2), N-vinyl-2 was applied to a nylon base material by radiation graft polymerization.
- Graft polymerized nylon fiber obtained by polymerizing pyrrolidone was added to the sample solution at 2
% by mass, and after shaking and contacting the sample liquid at a predetermined temperature (20° C.) for 1 hour, the graft polymerized fibers were removed to obtain a sample treatment liquid.

(3) Measurement of polyphenol concentration Iron tartrate method for black tea, EBC method for beer (EUROPEAN BREWERY CONVENTIO
Polyphenol concentrations were measured using the Folin-Ciocalt method for N. Analytica-EBC), wine, and apple juice. Specifically, measurements were performed as follows.

The iron tartrate method measures the absorbance at 540 nm of a purple component produced by reacting a polyphenol in a liquid with an iron tartrate reagent. A similar operation is performed using a standard substance such as ethyl gallate, and the amount of polyphenol is determined in terms of the compound.

In the EBC method, the amount of polyphenols is determined by making use of the property of coloring when polyphenols in a liquid react with iron salts. Carboxymethyl cellulose (CMC/EDTA) solution and E
After treating a sample with a DTA mixed solution and reacting trivalent iron ions with polyphenols in an alkaline solution containing a concentrated ammonia solution, the absorbance of the red color of the sample solution is measured at 600 nm with respect to a blank solution.

The Folin-Ciocalt method is based on the reduction of polyphenols in an alkaline solution. After adding a phenol reagent to the sample and stirring, adding a sodium carbonate solution and stirring, the sample solution is left at room temperature for about 2 hours. Measure the absorbance at 750 nm.

(4) Results Table 6 shows the polyphenol concentration and polyphenol removal rate before treatment when the nylon fibers graft-polymerized with N-vinyl-2-pyrrolidone were brought into contact with various beverages.

Example 6: Types of polymerizable monomers and characteristics for removing catechins from green tea (1) Preparation of green tea extract A green tea extract was obtained in the same manner as in Example 1 (1).

(2) Graft polymerization fiber treatment to green tea extract The green tea extract obtained in (1) above was treated with various polymerizable monomers (see Table 7) on a nylon base material by radiation graft polymerization. The graft polymerized nylon fiber body
It was added to the extract in an amount of 1% by mass and brought into contact with shaking at a predetermined temperature (20° C.) for 3 hours. N-vinyl-2-pyrrolidone, glycidyl methacrylate, triethylenediamine,
The functional group densities of the fibers graft-polymerized with sodium iminodiacetate and dimethylaminoethyl methacrylate are 3.9 mmol/g, 4.0 mmol/g, and 2.0 mmol, respectively.
l/g, 1.9 mmol/g, and 2.5 mmol/g. Thereafter, the graft polymerized nylon fibers were removed to obtain a green tea treatment liquid.

(3) Measurement of total catechin concentration As in (3) of Example 1, the total catechin concentration was measured and the total catechin removal rate was calculated. The total catechin concentration of the green tea extract before graft polymerization fiber treatment was 188.0 mg/100 mL.

(4) pH measurement Each of the green tea liquids obtained in (2) above was measured using a pH meter (manufactured by Kubota Corporation). The pH of the green tea extract before the graft polymerization fiber treatment was 5.88.

(5) Results The catechin removal rate, pH, and overall evaluation of various graft polymerized fibers were as shown in Table 7.

Among various polymerizable monomers, it was found that nylon fibers polymerized with N-vinyl-2-pyrrolidone have a high ability to adsorb catechin and produce good results with small pH fluctuations after contact. When producing green tea extract as a packaged beverage, additives for adjusting the pH affect the flavor, so in order to produce a beverage with good flavor, it is necessary to adjust the pH of the processing solution.
Although it is desirable to select an adsorbent with small fluctuations in H, nylon fibers polymerized with N-vinyl-2-pyrrolidone have small pH fluctuations and a high catechin removal rate, so other polymerized fibers may be used. It was found to be very advantageous compared to

Claims (7)

A tea beverage or its raw material is brought into contact with a polymer base material obtained by graft polymerization of a polymerizable monomer containing N-vinylalkylamide (however, xanthan gum and lignocellulose are excluded from the polymer base material). A method for producing a packaged black tea beverage with reduced polyphenol content, wherein the pH of the beverage or its raw material after contact with a polymeric base material is within a range of ±0.3 relative to the pH before contact. The manufacturing method within. The manufacturing method according to claim 1, wherein the polymeric base material is in the form of fibers, hollow fibers, nonwoven fabrics, or beads. The manufacturing method according to claim 1 or 2 , wherein the N-vinylalkylamide is N-vinyl-2-pyrrolidone. The manufacturing method according to any one of claims 1 to 3 , wherein the polymer base material is a polymer base material that has been subjected to a recycling treatment. 5. The manufacturing method according to claim 4 , wherein the regeneration treatment is carried out by bringing the polyphenol-adsorbed polymer base material into contact with a neutral regenerant, an alkaline regenerant, or an acidic regenerant. A tea beverage or its raw material is brought into contact with a polymer base material obtained by graft polymerization of a polymerizable monomer containing N-vinylalkylamide (however, xanthan gum and lignocellulose are excluded from the polymer base material). A method for reducing the polyphenol content in a packaged black tea beverage, wherein the pH of the beverage or its raw materials after contact with a polymeric base material is within a range of ±0.3 relative to the pH before contact. There is a method. 7. The method according to claim 6, wherein the polymeric substrate is in the form of fibers, hollow fibers, nonwoven fabrics, or beads.

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