JP7708997B2 - Method for producing polyphenol-containing gelatin - Google Patents

Description

The present invention relates to an industrial method for producing polyphenol-containing gelatin with reduced bitterness and astringency.

Polyphenols have been reported to have many physiologically active effects, including antioxidant effects, antihypertensive effects, and anticancer effects. Polyphenols have also been recognized to have effects such as suppressing blood sugar and blood cholesterol levels by promoting the metabolism of sugar and lipids, which are believed to cause obesity and diabetes, and various products and beverages containing polyphenols are commercially available. Recently, it has been reported that polyphenols affect the maintenance and improvement of homeostasis of the intestinal flora, attracting attention.

Polyphenol is a general term for plant components that have multiple phenolic hydroxyl groups in their molecules, and representative polyphenols include flavonoids, phenolic acids, ellagic acid, lignans, curcumin, and coumarin (Non-Patent Document 1: Wikipedia). The flavonoids mentioned above include catechins (rich in wine, tea, apples, blueberries, etc.), anthocyanidins (rich in grape skin, purple sweet potato, blueberries, etc.), rutin (rich in buckwheat), and isoflavones (rich in soybeans, kudzu, etc.), while non-flavonoids include tannins (astringent components found in tea, red wine, persimmons, bananas, etc.), phenolic acids (chlorogenic acid found in coffee), ellagic acid (rich in strawberries), sesamin, a type of lignan (rich in sesame seeds), curcumin (rich in turmeric), and coumarin (rich in cherry leaves, parsley, peaches, and citrus fruits) (Non-Patent Document 1).

Currently, examples of polyphenols used in foods and beverages include tea catechins, olive polyphenols, red wine polyphenols, grape seed polyphenols, apple polyphenols, soybean polyphenols, blackcurrant polyphenols, red shiso polyphenols, cacao polyphenols, green coffee extract, walnut polyphenols, chestnut astringent skin polyphenols, peanut astringent skin polyphenols, pine bark polyphenols, seaweed polyphenols, ginkgo leaf polyphenols, and tea (Theaceae) polyphenols.

However, foods and beverages with high concentrations of polyphenols that are expected to have a physiologically active effect tend to have a strong bitter and astringent taste that is not to the taste of most people, so improvements are needed.

As a method for reducing these bitterness and astringency, for example, the addition of cyclodextrin to tea-based beverages has been reported (e.g., Patent Documents 1 to 8). However, the method of adding cyclodextrin has the problem that the effect of reducing bitterness and astringency varies depending on the timing of addition in the manufacturing process, and it is not possible to obtain a uniform and stable effect of reducing bitterness and astringency. In addition, the ADI value (acceptable daily intake) of β-cyclodextrin is set at 5 mg/kg body weight/day, so there is the problem that the amount used is limited.

The phenomenon of polyphenols binding with proteins to form water-insoluble complexes has long been known in wine and beer brewing as haze. It has been reported that haze is a water-insoluble complex formed by the binding of proline-rich regions of proteins with hydrophobic regions of polyphenols (Non-Patent Document 2).

It has been reported that hydrophobic forces and hydrogen bonds are involved in the formation of precipitates between polyphenols, tannins, and proteins, and that proteins with high proline content tend to bind to polyphenols (Non-Patent Document 3).

The masking effect of various food ingredients on the astringency of chestnut astringent skin polyphenols was evaluated based on their ability to form precipitates with polyphenols, and it has been reported that gelatins, milk-derived proteins, methylcellulose, and other ingredients show high effectiveness (Non-Patent Document 4).

Methods for producing water-insoluble complexes of polyphenols and proteins have been reported, including, for example, a method in which a polyphenol solution is added to a protein solution while stirring and mixing to produce a complex (Patent Document 8), a method in which a soy protein extract and a tea extract are mixed in a beaker and then the pH is adjusted to 4.5 to precipitate the complex (Patent Document 9), and a method in which milk protein obtained by dialyzing green tea polyphenols and skim milk powder through a dialysis membrane is suspended in physiological saline to obtain a complex (Patent Document 10). However, no specific examples suitable for scaling up have been described for the production method of polyphenol-protein complexes, and there remain issues to be resolved as an industrial production method of the complex.

In addition, a method has been reported as an industrial method for producing a polyphenol-protein complex in which a lipid coating is formed on the surface of a polyphenol-containing powder and a protein powder in advance, and then a shear force is applied in an aqueous solution to mix them, thereby producing a complex with reduced bitterness and astringency (Patent Document 11). However, this method requires a special lipid coating production device for the powder in order to form a lipid coating on the polyphenol-containing powder and the protein powder.

Patent No. 3259758 Patent No. 3342698 Patent No. 3766660 Japanese Patent Application Publication No. 3-168046 JP 2005-245351 A JP 2008-118873 A JP 2010-45994 A Japanese Unexamined Patent Publication No. 202900/1999 JP 2002-68991 A JP 2007-8920 A Patent No. 5461349

"Wikipedia" (free encyclopedia) / Polyphenols (https://ja.wikipedia.org/wiki/%E3%83%9D%E3%83%AA%E3%83%95%E3%82%A7%E3%83%8E%E3%83%BC%E3%83%AB) Harry Craig et al. “Prevention of Protein-Polyphenol Haze in Beer using a Proline-Specific Proteinase” http://www. ib dasiapac. com. au/asia-pacific-activities/convention-proceedings/2006/Papers & Presentations/Craig & Paper. pdf Anders Bennick; Interaction of Plant Polyphenol with Salivary proteins, Crit. Rev. Oral Biol. Med. , 13(2), 184-196 (2002) Seiichi Higuchi et al., Development of functional foods using local food ingredients, Saitama Prefectural Industrial Technology Center Research Report, 7 (2009)

The objective of the present invention is to provide a method for producing polyphenol-containing materials with reduced bitterness and astringency using a substance that specifically adsorbs polyphenols and has no limit on the acceptable intake amount.

The inventors have discovered that by adding solid gelatin to a polyphenol-containing aqueous solution under heating and mixing to adsorb water-soluble polyphenols to the solid gelatin, solid polyphenol-containing gelatin with reduced bitterness and astringency can be produced easily and at low cost, and have completed the present invention.

That is, the present invention provides the following [1] to [3].

[1] A method for producing polyphenol-containing gelatin having low bitterness and astringency using water-soluble polyphenols as a raw material, comprising the steps of:
A first step of preparing a polyphenol-containing aqueous solution by extraction from a polyphenol-containing raw material or dissolving solid polyphenol in water to prepare a polyphenol-containing aqueous solution;
A second step of adding solid gelatin to the polyphenol-containing aqueous solution obtained in the first step while heating and mixing at 40 to 100°C to adsorb the water-soluble polyphenol to the solid gelatin (excluding the case where a polyphenol-containing powder and a protein-containing powder having a lipid coating formed thereon are mixed in an aqueous solution to destroy the lipid coating and form a water-insoluble complex of the polyphenol and the protein);
A third step of separating the gelatin fraction having the water-soluble polyphenol adsorbed thereto in the second step;
A step 4a of drying the water-containing precipitate fraction obtained in the step 3 and pulverizing it to obtain a polyphenol-containing gelatin powder;
A method for producing polyphenol-containing gelatin, comprising:

[2] The method for producing polyphenol-containing gelatin according to [1], wherein the solid gelatin is gelatin powder.

[3] The method for producing polyphenol-containing gelatin according to [1] or [2], wherein the amount of the solid gelatin used is 0.3 parts by mass or more per 1 part by mass of the water-soluble polyphenol contained in the polyphenol-containing aqueous solution.

According to the present invention, polyphenol-containing gelatin containing polyphenols with no limit on the acceptable intake amount and reduced bitterness and astringency, and a composition containing the same can be produced easily and at low cost.

FIG. 1 is a flow diagram showing an example of a method for producing polyphenol-containing gelatin according to the present invention.

The present invention will be described in detail below based on the embodiments, but the present invention is not limited to these embodiments.

<Method for producing polyphenol-containing gelatin with reduced bitterness and astringency>
The method for producing polyphenol-containing gelatin of the present invention is a method for producing polyphenol-containing gelatin having a reduced bitterness and astringency using water-soluble polyphenols as a raw material and solid gelatin as an adsorbent, and includes a step (hereinafter also referred to as the second step) of adding solid gelatin to a polyphenol-containing aqueous solution containing water-soluble polyphenols under heating and mixing to allow the solid gelatin to adsorb the water-soluble polyphenols in the polyphenol-containing aqueous solution.

The polyphenol-containing aqueous solution can be prepared by dissolving solid polyphenols in water, or a solution extracted from a plant material containing polyphenols with an aqueous solvent can be used.

Next, steps 1 to 4 of the present invention will be described in detail. First, each step of the present invention will be briefly described based on FIG. 1.

At the "start", first, a "polyphenol-containing raw material" is prepared, and a "polyphenol-containing aqueous solution" is prepared by extraction, or solid polyphenols are dissolved in water to prepare a "polyphenol-containing aqueous solution" (step 1). Next, solid gelatin is added to the polyphenol-containing aqueous solution obtained in step 1 under heating and mixing, and the water-soluble polyphenols are adsorbed to the solid gelatin (step 2). Furthermore, in step 2, the gelatin fraction that has adsorbed the water-soluble polyphenols is separated (step 3), and the precipitate fraction obtained in step 3 is dried and finely pulverized to recover polyphenol-containing gelatin powder (step 4), and the process is then "ended".

(1st step)
The polyphenol-containing aqueous solution used in the present invention can be prepared by dissolving solid polyphenol in water, or by extracting a polyphenol-containing raw material, such as a plant raw material, containing water-soluble polyphenol with an aqueous solvent.

The solid polyphenols used as raw materials in the present invention include polyphenols sold as food raw materials, such as catechin, proanthocyanidin, and isoflavone, and examples of plant raw materials containing water-soluble polyphenols include persimmon, grape, tea, peanut, and coffee, but the variety is not limited.

(Second process)
This process is a process in which solid gelatin is added to a polyphenol-containing aqueous solution under heating and mixing to adsorb water-soluble polyphenols to the solid gelatin. By the operation of this process, polyphenols, which are bitter and astringent components, are specifically adsorbed to the solid gelatin. In this way, a gelatin fraction having water-soluble polyphenols adsorbed thereto can be obtained. The gelatin fraction having water-soluble polyphenols adsorbed thereto produced by this treatment is produced as a solid material with good separation characteristics and sedimentation properties, so that it is easy to separate. In addition, by heating, microorganisms that are sensitive to heat and present in the polyphenol raw material and gelatin are also sterilized, so that the quality of the polyphenol-containing gelatin can be improved.

The mechanism by which water-soluble polyphenols are adsorbed to solid gelatin is not entirely clear, but the inventors speculate that when solid gelatin is added to water-soluble polyphenols such as heated persimmon juice, the helical structure of the gelatin molecules on the surface of the solid gelatin becomes a random coil molecular structure in a temperature-dependent manner, to which the water-soluble polyphenol molecules are quickly adsorbed. In addition, solid gelatin with water-soluble polyphenols adsorbed does not gel but forms as a precipitate, and the inventors speculate that this is because the water-soluble polyphenols are quickly adsorbed to the solid gelatin, making it unable to form a normal gelatin sol, and suppressing swelling due to the binding of water molecules, so that the gelatin is unable to regain its original helical structure even when cooled.

The content of water-soluble polyphenols in the polyphenol-containing aqueous solution used in this step is, in terms of tannic acid, preferably more than 0.1% (w/v), more preferably more than 1% (w/v), and is preferably 10% (w/v) or less, more preferably 7.5% (w/v) or less, and particularly preferably 5% (w/v) or less.

In this specification, the content of water-soluble polyphenols refers to the value measured by the Folin-Ciocalteu method using tannic acid as a standard, and specifically, may be measured in the same manner as in the examples.

In addition, solid gelatin is used in this process. Therefore, there is no dilution of the polyphenol solution as occurs when a gelatin solution is added, and it can be produced easily and efficiently even from raw materials such as 100% plant extract. In addition, the process of preparing the gelatin solution in advance can be omitted, which is simple and industrially advantageous. In addition, when a gelatin solution is used instead of solid gelatin, fine precipitates with poor separation and sedimentation properties are generated.

The solid gelatin used in this process is not particularly limited as long as it adsorbs water-soluble polyphenols when heated, but acid-treated gelatin and alkali-treated gelatin are preferred because they are commercially available for food use and are easy to obtain. Examples of such gelatin include those derived from pigs (skin, bones), cattle (skin, bones), fish (skin, scales), etc. One of these may be used alone, or two or more may be used in combination.

Examples of solid gelatin include gelatin powder, gelatin granules, and sheet gelatin. These may be used alone or in combination of two or more. Among these, gelatin powder is preferred from the viewpoints of the taste of polyphenol-containing gelatin, production efficiency, and handling properties. The solid gelatin may be prepared according to a known method or may be a commercially available product.

The amount of solid gelatin used may be determined according to the amount of water-soluble polyphenols contained in the polyphenol-containing aqueous solution. The amount of solid gelatin used is preferably 0.3 parts by mass or more, more preferably 0.7 parts by mass or more, and particularly preferably 1 part by mass or more per part by mass of water-soluble polyphenols (converted into tannic acid) contained in the polyphenol-containing aqueous solution, and from the viewpoint of production cost and production efficiency, it is preferably 3 parts by mass or less, more preferably 2 parts by mass or less per part by mass of water-soluble polyphenols (converted into tannic acid) contained in the polyphenol-containing aqueous solution.

The amount of solid gelatin used to obtain the desired polyphenol content in the resulting polyphenol-containing gelatin can be determined based on the results of a preliminary test using the concentration of water-soluble polyphenols in the polyphenol-containing aqueous solution, allowing fine adjustment of the polyphenol content of the resulting polyphenol-containing gelatin, and making it possible to obtain polyphenol-containing gelatin with a complex flavor that has a slight astringency.

The temperature when solid gelatin is added to the polyphenol-containing aqueous solution is 40°C or higher, more preferably 50°C or higher, and particularly preferably 60°C or higher, from the viewpoint of the adsorption rate of water-soluble polyphenols to solid gelatin, and is 100°C or lower, more preferably 90°C or lower, even more preferably 80°C or lower, and particularly preferably 70°C or lower, from the viewpoint of production cost and production efficiency.

The polyphenol-containing aqueous solution can be heated using a heat exchanger such as a plate heat exchanger or a tubular heat exchanger. In addition, it is preferable to maintain the processing temperature constant during heating and mixing via the jacket of the mixing tank. The time for mixing the solid gelatin added to the heated polyphenol-containing aqueous solution may be appropriately adjusted depending on the amount of the polyphenol-containing aqueous solution.

A specific example of the procedure for "adding solid gelatin to a polyphenol-containing aqueous solution while heating and mixing" is to (gradually) add solid gelatin to a polyphenol-containing aqueous solution that is being heated and mixed. By heating the aqueous solution in advance in this way and then contacting the polyphenol-containing aqueous solution with the solid gelatin, the generation of aggregates is suppressed and the adsorption of water-soluble polyphenols is facilitated.

In addition, the mixing operation of the polyphenol-containing aqueous solution can be a mixing operation by stirring using a normal stirrer.

(Third step)
The method for producing polyphenol-containing gelatin of the present invention preferably further comprises a third step of separating the gelatin fraction having adsorbed water-soluble polyphenols in the second step. The gelatin fraction having adsorbed water-soluble polyphenols is a solid matter having good separation properties and sedimentation properties, and therefore can be easily separated by a solid-liquid separation operation such as centrifugation, filtration, or screw press.

Of the above solid-liquid separation operations, centrifugation can be carried out using a conventional centrifuge such as a separation plate type, a cylindrical type, or a decanter type. The rotation speed of the centrifuge is preferably 3,000 to 100,000 rpm, more preferably 5,000 to 20,000 rpm, and particularly preferably 5,000 to 10,000 rpm. In addition, in the case of mass production, it is preferable to use a continuous centrifuge, but a batch centrifuge can also be used.

The gelatin fraction with adsorbed water-soluble polyphenols separated in the third step can be used as a food ingredient, or can be separated into water-soluble polyphenols and gelatin by solvent extraction or the like. This gelatin can be reused to adsorb water-soluble polyphenols, and the water-soluble polyphenols separated from the gelatin can be used as a raw material for disinfectants, persimmon tannins, soaps, deodorants, cosmetics, paints, etc.

(Step 4a)
The polyphenol-containing gelatin separated in the third step is a wet precipitate cake (precipitate fraction) containing water, which can be dried and pulverized to obtain polyphenol-containing gelatin powder.

Drying can be performed using a conventional dryer such as a freeze dryer, vacuum dryer, hot air dryer, infrared dryer, or microwave heating dryer. The drying temperature is preferably 50°C or less, more preferably 40°C or less, and particularly preferably 30°C or less.

After drying, the gelatin powder containing polyphenols can be obtained by finely pulverizing it using a fine grinding machine such as a bead mill, ball mill, rod mill, or jet mill, or a grinding machine such as a rotary stone mill.

<Composition containing polyphenol-containing gelatin>
The composition containing polyphenol-containing gelatin of the present specification contains polyphenol-containing gelatin produced by the above-mentioned method for producing polyphenol-containing gelatin and a dispersant. This composition has reduced bitterness and astringency of polyphenols, and has good extractability from gelatin. That is, gelatin is used to reduce the bitterness and astringency of polyphenols, and polyphenols are adsorbed to this gelatin, but on the other hand, when polyphenols are ingested, the ingested polyphenols need to be sufficiently released from the gelatin. If the release from the gelatin is not sufficient, for example, when polyphenol-containing gelatin powder is used in health foods, the sustained release of polyphenols from the powder particles is thought to decrease. As a result, there is a risk of problems such as an increased intake. Therefore, as in the composition containing polyphenol-containing gelatin of the present specification, by suspending the precipitate of moist polyphenol-containing gelatin containing water in a dispersant and forming it into fine particles, it becomes possible to easily release the polyphenols adsorbed to the gelatin.

Examples of dispersants include water-soluble polymers that have anti-precipitation, anti-aggregation, and emulsification functions. There are no particular limitations on the water-soluble polymers as long as they have the above functions, but examples include thickening polysaccharides such as xanthan gum and guar gum, natural polymers such as sodium alginate, corn starch, sodium chondroitin sulfate, and sodium hyaluronate, semi-synthetic polymers such as carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, and cationized guar gum, and synthetic polymers such as carboxyvinyl polymers, polyacrylic acid, polyvinylpyrrolidone, and polyvinyl alcohol. Aqueous solutions of thickening polysaccharides are characterized by high non-Newtonian fluidity and pseudoplastic fluidity. In other words, aqueous solutions of thickening polysaccharides have a high static viscosity (good effect of inhibiting the settling of fine particles), but the viscosity drops significantly when shear is applied.

<Method for producing a composition containing polyphenol-containing gelatin with reduced bitterness and astringency>
The method for producing a composition containing polyphenol-containing gelatin in the present specification is a method for producing a composition containing polyphenol-containing gelatin with reduced bitterness and astringency using water-soluble polyphenols as a raw material and solid gelatin as an adsorbent, and includes the following steps: a first step of preparing a polyphenol-containing aqueous solution by extraction from a polyphenol-containing raw material, or dissolving solid polyphenols in water to prepare a polyphenol-containing aqueous solution; a second step of adding solid gelatin to the polyphenol-containing aqueous solution obtained in the first step under heating and mixing to adsorb the water-soluble polyphenols to the solid gelatin; a third step of separating the gelatin fraction that has adsorbed the water-soluble polyphenols in the second step; and a fourth step of suspending the water-containing precipitate fraction obtained in the third step in a dispersant to form fine particles, thereby obtaining a suspension solution of polyphenol-containing gelatin.

This method can obtain a composition in which the bitterness and astringency of polyphenols are reduced, and can also obtain a composition in which polyphenols are easily extracted from gelatin. In other words, as described above, the bitterness and astringency of polyphenols can be reduced by using gelatin, but on the other hand, after ingestion of polyphenol-containing gelatin, the ingested polyphenols must be sufficiently released from the gelatin in an effective state. However, if effective polyphenols are not released from the gelatin, for example, when polyphenol-containing gelatin powder is used in health foods, the sustained release of polyphenols from the powder particles is thought to decrease. As a result, problems such as an increased intake may occur. According to the manufacturing method of the present specification, a composition can be produced in which the bitterness and astringency of polyphenols are reduced when ingested, and polyphenols are released in an effective state after ingestion.

(1st process to 3rd process)
The first to third steps can be the same as those in the above-mentioned <Method for producing polyphenol-containing gelatin with reduced bitterness and astringency>.

(Step 4b)
Step 4b is a step in which the water-containing precipitate fraction obtained in step 3 is suspended in a dispersant to form fine particles, thereby obtaining a suspension solution of polyphenol-containing gelatin. The dispersant used in this step can be any of the dispersants described in the above section <Composition containing polyphenol-containing gelatin>.

Examples of a method for suspending the precipitate fraction in a dispersant include a method in which a wet precipitate cake containing water is suspended in a dispersant (e.g., a water-soluble polymer having anti-precipitation, anti-aggregation, emulsifying, etc.) and then pulverized into fine particles using a wet fine grinding machine such as a wet bead mill or a wet ball mill, and thus a suspension solution of wet polyphenol-containing gelatin can be obtained.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

The concentration of water-soluble polyphenols was measured by the Folin-Ciocalteu method using phenol reagent (Nacalai Tesque) and tannic acid (Yoneyama Pharmaceutical Co., Ltd.) as the standard.

(Preparation Example 1: Preparation of persimmon tannin-containing gelatin from persimmon extract)
[Preparation of extract]
Approximately 8 kg (7.4 L) of juice was obtained from approximately 10 kg of astringent persimmon (Atago, Ehime Prefecture) using a juicer (Panasonic "MJ-L500-S"). The juice exhibited an orange color due to carotenoids and was turbid, so it was centrifuged at 9,500 rpm for 30 minutes using a high-speed refrigerated centrifuge to remove the water-insoluble carotenoid-containing precipitate fraction.

As a result, about 7.5 kg (total recovery rate of about 75%) of clear persimmon extract containing water-soluble persimmon tannins (persimmon polyphenols) was obtained. The concentration of water-soluble persimmon tannins in the extract was measured using the Folin-Ciocalteu method, and the concentration was 24.2 mg/mL (tannic acid equivalent).

[Study of gelatin addition conditions (temperature)]
3.6 g of gelatin powder (Nitta Gelatin Co., Ltd.) was gradually added to 100 mL of the astringent persimmon extract obtained above under the temperature and mixing conditions shown in Table 1, and the mixture was thoroughly mixed and stirred for about 10 minutes at that temperature, and then left at room temperature. Then, the mixture was centrifuged at 4 to 8°C and 6,800 rpm for 30 minutes. The resulting centrifugal supernatant was subjected to measurement and evaluation of the concentration of remaining water-soluble persimmon tannins. The results are shown in Table 1.

As shown in Table 1, at temperatures above 40°C, water-soluble persimmon tannins began to be adsorbed by solid gelatin, forming a precipitate that was easily separated from the extract, and at temperatures above 60°C, the adsorption rate was approximately 97%, meaning that most of the water-soluble persimmon tannins in the extract were adsorbed by gelatin.

[Study of gelatin addition amount]
To 100 mL of the astringent persimmon extract obtained above (water-soluble persimmon tannin concentration: 24.2 mg/mL), 0.5 parts by mass, 0.75 parts by mass, 1.0 parts by mass, or 1.5 parts by mass of gelatin powder (manufactured by Nitta Gelatin Co., Ltd.) per 1 part by mass of water-soluble persimmon tannin (converted to tannic acid) was gradually added while heating and mixing at 60 to 70°C, and the mixture was thoroughly mixed and stirred at that temperature for about 10 minutes, and then left at room temperature. Then, the mixture was centrifuged at 4 to 8°C and 6,800 rpm for 30 minutes.

The concentration of water-soluble persimmon tannin remaining in the centrifugal supernatant was measured to determine the rate of adsorption to gelatin. The results are shown in Table 2.

When the amount of solid gelatin used was 1 part by mass or more per 1 part by mass of water-soluble persimmon tannin, most of the water-soluble persimmon tannin was adsorbed by the gelatin.

[Production of persimmon tannin-containing gelatin]
50 g of gelatin powder (Nitta Gelatin Co., Ltd.) was gradually added to 2 L of the astringent persimmon extract obtained above while heating and mixing at 60-70°C, and the mixture was thoroughly mixed and stirred for about 10 minutes at that temperature, and then left at room temperature. Then, the mixture was centrifuged at 4-8°C and 6,800 rpm for 30 minutes. The precipitated fraction was freeze-dried and then finely pulverized to obtain about 60 g of gelatin powder containing persimmon tannin. No astringency was felt when this powder was put in the mouth.

[Preparation of a suspension containing wet persimmon tannin-containing gelatin]
50 g of gelatin powder (Nitta Gelatin Co., Ltd.) was gradually added to 2 L of the astringent persimmon extract obtained above under heating and mixing at 60-70 ° C., and the mixture was thoroughly mixed and stirred at that temperature for about 10 minutes, and then left at room temperature. Then, centrifugation was performed at 4-8 ° C. and 6,800 rpm for 30 minutes. The precipitated fraction was dispersed in 2 L of a dispersant/0.5% xanthan gum aqueous solution (xanthan gum: Kimika Xanthan PH-EC, Kimika Co., Ltd.), and then microparticulated using a wet ball mill (Dyno Mill MULTI-LAB type, Shinmaru Enterprises Co., Ltd.), to obtain about 2 L of a suspension solution of wet persimmon tannin-containing gelatin. No astringency was felt even when this suspension solution was held in the mouth.

(Preparation Example 2: Production of catechin-containing gelatin from catechin raw material)
A 2% aqueous solution of 1000 mL was prepared using commercially available tea catechin powder (Taiyo Kagaku Co., Ltd. "Sunphenon 90S": 80% or more polyphenol) as the catechin raw material. 20 g of gelatin powder (Nitta Gelatin Co., Ltd.) was gradually added to this aqueous solution under heating and mixing at 60-70°C, and the mixture was thoroughly mixed and stirred for about 10 minutes at that temperature, and then left at room temperature. Then, the mixture was centrifuged at 4-8°C and 6,800 rpm for 30 minutes. The residual catechin concentration in the supernatant was 0.8 mg/mL, and most of the catechin was adsorbed by gelatin. The precipitate fraction was freeze-dried and then finely pulverized to obtain about 25 g of tea catechin-containing gelatin powder. This powder did not taste bitter or astringent when held in the mouth.

(Preparation Example 3: Production of proanthocyanidin-containing gelatin from proanthocyanidin raw material)
A 2% aqueous solution of 1000 mL was prepared using commercially available grape seed polyphenol (Kikkoman Biochemifa Co., Ltd. "Gravynol-SE") as a proanthocyanidin raw material. 20 g of gelatin powder (Nitta Gelatin Co., Ltd.) was gradually added to this aqueous solution under heating and mixing at 40 ° C. to 50 ° C., and the mixture was thoroughly mixed and stirred for about 10 minutes at that temperature, and then left at room temperature. Then, centrifugation was performed at 4 to 8 ° C. and 6,800 rpm for 30 minutes. The residual proanthocyanidin concentration in the supernatant was 0.7 mg / mL, and most of it was adsorbed to gelatin. The precipitate fraction was freeze-dried and then finely pulverized to obtain about 2 g of grape seed proanthocyanidin-containing gelatin powder. Even when this powder was held in the mouth, no bitterness or astringency was felt.

According to the present invention, a polyphenol-containing material with reduced bitterness and astringency can be provided by using a substance that specifically adsorbs polyphenols and has no limit on the allowable intake amount, and therefore the present invention can be used industrially with great advantage.

Claims (3)

A method for producing polyphenol-containing gelatin having low bitterness and astringency using water-soluble polyphenol as a raw material, comprising the steps of:
A first step of preparing a polyphenol-containing aqueous solution by extraction from a polyphenol-containing raw material or dissolving solid polyphenol in water to prepare a polyphenol-containing aqueous solution;
A second step of adding solid gelatin to the polyphenol-containing aqueous solution obtained in the first step while heating and mixing at 40 to 100°C to adsorb the water-soluble polyphenol to the solid gelatin (excluding the case where a polyphenol-containing powder and a protein-containing powder having a lipid coating formed thereon are mixed in an aqueous solution to destroy the lipid coating and form a water-insoluble complex of the polyphenol and the protein);
A third step of separating the gelatin fraction having the water-soluble polyphenol adsorbed thereto in the second step;
A step 4a of drying the water-containing precipitate fraction obtained in the step 3 and pulverizing it to obtain a polyphenol-containing gelatin powder;
A method for producing polyphenol-containing gelatin, comprising: The method for producing polyphenol-containing gelatin according to claim 1, wherein the solid gelatin is gelatin powder. 3. The method for producing polyphenol-containing gelatin according to claim 1, wherein the amount of the solid gelatin used is 0.3 parts by mass or more per 1 part by mass of the water-soluble polyphenol contained in the polyphenol-containing aqueous solution.