JP2003128664A - Polyphenol salt, food product and beverage, and method for reducing acerbity, bitterness or astringency of polyphenol or extract containing polyphenol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide polyphenol salts, food products or beverages having high physiological activities with reduced acerbity, bitterness and astringency, and also to provide a method for reducing the acerbity, bitterness and astringency of polyphenols or extracts containing polyphenols. SOLUTION: Polyphenol salts including a sodium salt, calcium salt, magnesium salt and potassium salt, and food products containing the polyphenol salts are provided. Food products which contain the extract of a polyphenol- containing plant neutralized with sodium hydroxide, calcium hydroxide, magnesium hydroxide or potassium hydroxide are also provided. In addition, beverages obtained by neutralizing the polyphenol-containing extract with alkali compounds are also provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for reducing astringency, bitterness or astringency of polyphenol salts, foods, beverages and polyphenols or polyphenol-containing extracts.

[0002]

2. Description of the Related Art Polyphenols typified by catechin are natural compounds widely contained in various plants such as tea and cacao, and have antibacterial activity, antioxidant activity, anticaries activity, antiviral activity, Since it has various physiological activities such as antiallergic activity, α-amylase inhibitory activity, blood pressure elevation inhibitory activity, blood cholesterol lowering activity,
Its application to health foods is drawing attention. However, polyphenols have astringency, bitterness or astringency (hereinafter,
It is called "astringency". There is a problem in that when a food containing a large amount of this is ingested, a noticeable astringency is felt. To reduce such astringency, sacrifice the physiological activity of polyphenols,
The intake of polyphenols or the addition of polyphenols to foods had to be reduced.

[0003]

SUMMARY OF THE INVENTION The main object of the present invention is to provide a polyphenol salt, a food and a beverage, in which astringency and the like are reduced and a high physiologically active effect is obtained. Another object of the present invention is to provide a method for reducing the astringency of polyphenols and polyphenol-containing extracts.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors reduced the astringency and the like of polyphenol by using polyphenol as a specific polyphenol salt, and The present inventors have found the new fact that this polyphenol salt returns to the original polyphenol and exerts its original physiological activity in an acidic environment equivalent to that in the stomach, and has completed the present invention.

That is, the polyphenol salt of the present invention is
It is characterized in that it is a sodium salt, calcium salt, magnesium salt or potassium salt of polyphenol. This polyphenol salt has reduced astringency and the like,
A large amount can be ingested, and since it returns to the original polyphenol in the stomach, a high physiologically active effect due to the large amount is expected. Further, since the polyphenol salt has improved water solubility as compared with polyphenol, turbidity and precipitates are less likely to occur when it is used as an aqueous solution. This polyphenol salt is preferably used as a food additive or a food material.

The food of the present invention is characterized by containing the above polyphenol salt. In the present invention, in addition to neutralizing the polyphenol itself, the polyphenol-containing plant extract may be neutralized and added to the food.

That is, another food of the present invention contains an extract of a polyphenol-containing plant neutralized with an alkali selected from the group consisting of sodium hydroxide, calcium hydroxide, magnesium hydroxide and potassium hydroxide. Characterize.

The food products in the present invention include solid food products, cream-like or jam-like semi-liquid food products, gel food products, beverages and the like, as well as food additives and food materials added thereto. Specific examples of the above foods include beverages,
Baked goods, gum, candy, chocolate, gummy,
Examples include jelly, dairy products, instant noodles, ice cream, frozen desserts, and bread.

Further, in the present invention, the beverage itself, which is an extract of polyphenol-containing tea leaves, may be neutralized. That is, the beverage of the present invention is characterized by being obtained by neutralizing an extract of tea leaves containing polyphenol with an alkali selected from the group consisting of sodium hydroxide, calcium hydroxide, magnesium hydroxide and potassium hydroxide.

The method for reducing the astringency, bitterness or astringency of polyphenols according to the present invention is a polyphenol salt obtained by using polyphenol as an alkali selected from the group consisting of sodium hydroxide, calcium hydroxide, magnesium hydroxide and potassium hydroxide. It is characterized by

The method for reducing the astringency, bitterness or astringency of a polyphenol-containing extract according to the present invention is a method in which the polyphenol-containing plant extract is selected from the group consisting of sodium hydroxide, calcium hydroxide, magnesium hydroxide and potassium hydroxide. It is characterized by being neutralized with a selected alkali.

In the present invention, "neutralize" means
It means adjusting the pH to a range of 6.5 to 7.0, preferably 6.8 to 7.0.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below.

1. Polyphenol Salt The polyphenol salt of the present invention is a sodium salt, calcium salt, magnesium salt or potassium salt of polyphenol.

The polyphenol is a compound having two or more phenolic hydroxyl groups on the same benzene ring. Examples of the polyphenol used in the present invention include those that are edible and include, for example, epicatechin, epicatechin gallate, epigallocatechin,
Epigallocatechin gallate, catechin, gallocatechin,
Examples include catechin gallate, gallocatechin gallate, leucoanthocyanin, gallic acid, gallate, ellagic acid, etc., all of which have astringency. These polyphenols may be synthetic ones or may be ones extracted and isolated from the plants described later.

In the polyphenol salt, the hydrogen atom of the phenolic hydroxyl group of the polyphenol is sodium,
It has been replaced with calcium, magnesium or potassium. The pH of this polyphenol salt is adjusted to about 6.5 to 7.0, preferably about 6.8 to 7.0 by adding sodium hydroxide, calcium hydroxide, magnesium hydroxide or potassium hydroxide to an aqueous polyphenol solution. It is obtained by

The alkali such as sodium hydroxide is
The polyphenol aqueous solution may be added in the form of a solid, but it is preferably added in the form of an aqueous solution. As the alkali, the above-mentioned hydroxide is preferable because it is necessary that the polyphenol is converted into the polyphenol salt by the neutralization reaction. It should be noted that food additives such as baking soda and brackish water may be used instead of the above alkali.

If necessary, the obtained polyphenol salt aqueous solution may be dried and processed into powder or the like.
When powdered, additives such as dextrin may be added as necessary. The means for drying is not particularly limited, and for example, a fluidized bed dryer or the like can be used. The polyphenol salt in which the astringency and the like are reduced in this manner can be ingested as it is, but can also be ingested by adding it to foods, as described later.

2. Extract As described above, the polyphenol may be extracted and isolated from the plant. Examples of such polyphenol-containing plants include tea leaves, beans, fruits, root vegetables, mushrooms, and the like, and specifically, for example, green tea leaves, oolong tea leaves, black tea leaves, cacao beans, apple fruits, persimmon leaves. Examples include fruits and potatoes. Examples of plants containing polyphenols other than those mentioned above include Eucalyptus plants. The part of the Eucalyptus plant used for extraction is not particularly limited, but examples thereof include leaves, fruits, buds, stems, roots, and the like, with leaves being particularly preferred.

Extraction may be carried out by a method which is usually used depending on the type of plant. Specifically, for example, the above-mentioned plant (which has been processed into powder or the like if necessary) is mixed with water, an organic solvent, a mixture thereof, or the like to extract the active ingredient. Examples of the organic solvent include lower alcohols such as methanol, ethanol and propanol, ethers such as acetone, ethyl acetate and diethyl ether. The extraction method is not particularly limited, and normal temperature homogenization extraction, reflux extraction, supercritical fluid extraction and the like can be used. After extraction, the obtained extract may be further extracted with water-saturated n-butanol, ethyl acetate or the like, and the obtained extract may be extracted with water-containing ethanol or the like. Since the extract thus obtained is obtained by the extraction treatment from the above plant, there is no problem in safety even if the fractionation and purification are insufficient.

After the extraction, the polyphenol may be isolated by using adsorption chromatography, partition chromatography, ion exchange chromatography and the like, and further purified by a conventional method. The extract thus obtained is subjected to a reaction for producing a polyphenol salt.

The polyphenol-containing plant extract obtained as described above has a pH of about 6.5 to 7.0, preferably about 6.8, by adding an alkali such as sodium hydroxide to the extract. By adjusting to ~ 7.0, the astringency and the like are reduced. The alkali may be added to the polyphenol aqueous solution in the form of a solid, but it is preferable to add the alkali in the form of an aqueous solution. If necessary,
The extract may be dried and processed into powder or the like.
When powdered, additives such as dextrin may be added as necessary. The means for drying is not particularly limited, and for example, a fluidized bed dryer or the like can be used. The polyphenol-containing extract in which the astringency and the like are reduced in this way can be ingested as it is, but can also be ingested by adding it to foods, as described later.

3. Food The food of the present invention contains (1) a product obtained by adding the polyphenol salt obtained in 1 above to a food product, (2) a product obtained by adding the extract neutralized in 2 above to a food product, and (3) a polyphenol It is obtained by directly adding an alkali to a food product.

Examples of the foods include solid foods, cream-like or jam-like semi-liquid foods, gel foods, beverages and the like, as well as food additives and food materials added to these, specifically, Examples thereof include beverages, baked goods, gum, candy, chocolate, gummy, jelly, dairy products, instant noodles, ice cream, frozen desserts, and bread.

(1) When adding polyphenol salt to food When adding polyphenol salt to food, it may be added in the form of an aqueous solution or may be dried and added in the form of solid such as powder. Good. The amount of the polyphenol salt added to the food is not particularly limited, and may be appropriately determined depending on the form of the food, taste and the like. Specifically, for example, in the case of a beverage, it is preferable to add about 50 to 100 mg of polyphenol salt to 100 mL of the beverage. In the case of solids such as baked goods, gum and chocolate, 100g of solids
It is advisable to add about 50 to 1000 mg of polyphenol salt.

(2) Addition of Neutralized Extract to Food When adding this extract to food, it may be added in the form of an aqueous solution or powdered by drying, as described above. May be added in a solid form such as. The amount of the extract added to the food is not particularly limited and may be appropriately determined depending on the form of the food, taste and the like. Specifically, for example, in the case of a beverage, the polyphenol salt-containing extract is preferably added to 100 mL of the beverage so that the amount of the polyphenol salt contained in the beverage is about 50 to 100 mg. In the case of solids such as baked goods, gum, and chocolate, it is preferable to add the polyphenol salt-containing extract so that the amount of the polyphenol salt contained in the food is about 50 to 1000 mg based on 100 g of the solid. .

(3) When an alkali is directly added to a polyphenol-containing food to neutralize it, the alkali such as sodium hydroxide is added to the polyphenol-containing food to adjust the pH to about 6.5 to 7.0. Preferably, it may be adjusted to about 6.8 to 7.0. The alkali may be added to the polyphenol aqueous solution in the form of a solid, but it is preferable to add it as an aqueous solution. The obtained food can be processed into a liquid, solid, cream, jam, gel, or other food form, if necessary. As a result, a food product with reduced astringency is obtained.

The food containing polyphenol includes the case where the material constituting the food originally contained polyphenol, the case where polyphenol was added to the food later, and the like.

There are no particular restrictions on the various components that are blended in the food together with the polyphenol salt, and various commonly used components can be used. Examples of such components include glucose, fructose, sucrose, maltose, sorbitol, stevioside, corn syrup, lactose, citric acid, tartaric acid, malic acid, succinic acid, lactic acid, L-ascorbic acid, dl-α-tocopherol, Glycerin, propylene glycol, glycerin fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, gum arabic, carrageenan, casein, gelatin, pectin, agar, vitamin B group, nicotinic acid amide, pantothene Examples thereof include calcium acid, amino acids, calcium salts, dyes, flavors, preservatives, and the like, and these may be appropriately mixed depending on the type of food.

For adjusting the pH, the alkali,
In addition to baking soda and brackish water, vitamin C and the like can be used. Further, the food of the present invention can also be obtained by a means in which the above (1) to (3) are used in combination.

[0031]

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

Example 1 <Production of polyphenol salt>"Catepure" manufactured by Nippon Shinyaku Co., Ltd. (components: total polyphenol content 94.7%, total catechin content 86.3%, epigallocatechin gallate content 4)
2.4%) 1 g was dissolved in 50 g of ion-exchanged water. The pH of the obtained aqueous solution was about 4.5. This aqueous solution was neutralized with a 0.1N aqueous sodium hydroxide solution to adjust the pH to 7.0. The neutralized aqueous solution was freeze-dried to obtain about 1 g of polyphenol salt.

Example 2 <Green Tea Beverage> 10 g of green tea leaf was placed in a container and 500 g of water at 80 ° C. was poured. After 5 minutes, the green tea leaf was filtered off to obtain a green tea extract (pH about 6). After cooling this green tea extract to room temperature, a 0.1N sodium hydroxide aqueous solution was added to adjust the pH to 7.0 to obtain a green tea beverage.

Comparative Example 1 A green tea beverage was obtained in the same manner as in Example 2 except that it was not neutralized with an aqueous sodium hydroxide solution.

Comparative Example 2 A green tea beverage was obtained in the same manner as in Example 2 except that half the amount of green tea leaves (5 g) of Example 2 was placed in a container and was not neutralized with an aqueous sodium hydroxide solution.

When the green tea beverages obtained in Example 2, Comparative Example 1 and Comparative Example 2 were compared with each other by 5 expert panelists, all the expert panelists had an excessive astringency in Comparative Example 1, and Example 2 in which the amount of green tea leaves was the same as that of Example 1 had a moderate astringency, and Comparative Example 2 in which the amount of green tea leaves was half that of Example 2 had a moderate astringency similar to that of Example 2. did.

Example 3 <Mixed Tea Beverage> Tea leaves and water were put in a container at a ratio shown in Table 1 and mixed.

[Table 1] After 10 minutes, the tea leaves were filtered off to obtain a mixed tea extract (pH about 6). Sodium bicarbonate was added to this extract to adjust the pH to 7.0, and the mixture was cooled to room temperature. Then, 0.5 g of the polyphenol salt obtained in Example 1 was added to 1000 g of the cooled extract to obtain a mixed tea beverage (pH
7.0).

Comparative Example 3 A mixed tea beverage was obtained in the same manner as in Example 3 except that 0.5 g of "Catepure" (described above) manufactured by Nippon Shinyaku Co., Ltd. was added instead of the polyphenol salt obtained in Example 1. It was

When the mixed tea beverages obtained in Example 3 and Comparative Example 3 were compared with each other by 5 specialized panelists, all of the specialized panelists had an excessive astringency in Comparative Example 3, and Example 3
Replied that it had a good astringency.

Example 4 <Cookie> Using the materials shown in Table 2, a cookie was prepared by the following procedure.

[Table 2] (Preparation procedure) (1) The butter was stirred well until it became creamy. (2) Powdered sugar was added to the stirred butter in 3 portions and mixed. Next, egg yolk was added and further stirred. (3) The baking powder and the polyphenol salt obtained in Example 1 were mixed with this, and 60 g of sieved wheat flour was added and stirred well. Then, the rest of the flour was added, and the mixture was stirred well and left to stand in the refrigerator for 1 hour. (4) Then, the mixture taken out from the refrigerator is 3 cm in diameter.
Shaped like a stick. (5) This was wrapped with wrap film and cooled in a refrigerator until it became sufficiently hard. (6) Then, the rod-shaped solid substance taken out from the refrigerator was cut into slices having a thickness of about 5 to 6 mm. (7) The sliced solid matter was placed in an oven preheated to 180 ° C. and baked for an appropriate time to obtain a cookie.

Example 5 A cookie was prepared in the same manner as in Example 4 except that the amount of polyphenol salt added was 3 g and the amount of wheat flour added was 237 g.

Example 6 A cookie was prepared in the same manner as in Example 4 except that the amount of polyphenol salt added was 5 g and the amount of wheat flour added was 235 g.

Comparative Example 4 "Catepure" manufactured by Nippon Shinyaku Co., Ltd. in place of the polyphenol salt
In the same manner as in Example 4 except that 1 g (of the above) was added,
I made a cookie.

Comparative Example 5 "Catepure" manufactured by Nippon Shinyaku Co., Ltd. in place of the polyphenol salt
Except that the amount of wheat flour added was 237 g,
A cookie was prepared in the same manner as in Example 4.

Comparative Example 6 "Catepure" manufactured by Nippon Shinyaku Co., Ltd. in place of the polyphenol salt
Except that the amount of wheat flour added was 235 g,
A cookie was prepared in the same manner as in Example 4.

Sensory tests were carried out on the astringency, bitterness and astringency of the cookies obtained in Examples 4 to 6 and Comparative Examples 4 to 6. The evaluation was performed by 6 professional panelists based on the following evaluation criteria. Table 3 shows the number of people who met the respective evaluation criteria as a result of the inspection. (Evaluation Criteria) ○: Astringency, bitterness and astringency are not felt. Δ: Slightly astringent, bitter and astringent. X: A fairly astringent, bitter and astringent taste is felt.

[Table 3]

As shown in Table 3, the astringency, bitterness and astringent taste were reduced in Examples 4 to 6 to which the polyphenol salt was added, as compared to Comparative Examples 4 to 6 to which "Catepure" was added. I understood.

Test Example 1 <Confirmation of the effect of reducing astringency and the like> A sensory test was conducted on the astringency, bitterness and astringency of the aqueous solution A of "Catepure" manufactured by Nippon Shinyaku Co., Ltd. and the aqueous solution B of the polyphenol salt obtained in Example 1. Carried out. That is, "catapure" and the polyphenol salt are diluted with ion-exchanged water to give 0.1
25 wt% aqueous solutions A and B were obtained respectively. Then, the aqueous solution A was gradually diluted with ion-exchanged water until the astringency, bitterness and astringent taste of the aqueous solution A became similar to the astringency, bitterness and astringent taste of the aqueous solution B, and the sensory test was repeated. The evaluation was carried out by 5 specialized panelists. As a result, when all the expert panelists judged that the astringency, bitterness and astringency of the aqueous solution A and the aqueous solution B were equal, the concentration of the aqueous solution A was 0.04% by weight. Thus, it can be said that the astringency, bitterness and astringency of the polyphenol salt obtained in Example 1 are reduced to about 1/3 that of "catapure".

Test Example 2 <Relationship between pH and polyphenol structure> In order to investigate the relationship between the structure of EGCg in an aqueous solution of epigallocatechin gallate (hereinafter referred to as "EGCg") and the pH of the aqueous solution, the following test was conducted. Carried out.

1 g of EGCg (purity 80%) was dissolved in 500 ml of deionized water to obtain an EGCg aqueous solution having a pH of 4.5. The pH is raised by adding an appropriate amount of 0.1N sodium hydroxide aqueous solution to this EGCg aqueous solution,
To obtain EGCg aqueous solutions of 5.0, 5.9, 6.5 and 7.0, respectively. Next, a part of the EGCg aqueous solution having a pH of 7.0 was collected, and the pH was lowered by adding an appropriate amount of 0.1 N hydrochloric acid to the pH of 6.5, 6.0,
EGCg aqueous solutions of 5.3, 3.9, 3.0 and 2.2 were obtained, respectively.

The UV absorption spectra of 11 kinds of EGCg aqueous solutions having different pH values were measured as described above. UV2200A manufactured by Shimadzu Corporation was used for the measurement. The absorption spectrum of each aqueous solution obtained by this measurement had a peak near a wavelength of 273 nm.
This peak is an absorption spectrum of a phenolic hydroxyl group. Therefore, by comparing the peak heights, the structural change of EGCg in the EGCg aqueous solution can be evaluated. That is, the lower the peak height is, the more the hydrogen atom of the phenolic hydroxyl group is replaced with sodium.

FIG. 1 is a graph showing the relationship between the peak height near the wavelength of 273 nm and the pH of the EGCg aqueous solution. As shown in Fig. 1, in the process of changing the pH from 4.5 to 7.0 with an aqueous sodium hydroxide solution (plotted with black circles in Fig. 1), the peak height sharply decreased from around pH 6.0. is doing. That is, the polyphenol salt (EGCg in the EGCg aqueous solution from about pH 6.0)
It shows that the sodium salt) sharply increases and the phenolic hydroxyl group sharply decreases.

On the other hand, the pH was adjusted to 7.0 to 2.2 with hydrochloric acid.
In the process of changing to (indicated by a white triangle in FIG. 1), the peak height increased sharply from pH 7.0 to 6.0, and thereafter, the peak height gradually increased to pH 2.2. It's getting higher. That is, it can be seen that the phenolic hydroxyl group is restored and increases as the pH decreases. In this case, the restoration rate of the phenolic hydroxyl group (based on the EGCg aqueous solution of pH 4.5) is less than 38% at the time when the pH is reduced to 6.5, but it is restored when the pH is reduced to 2.2. The rate was about 92%.

From the above results, in a weak acidic environment where the pH of the EGCg aqueous solution is about 6.5 or in a neutral environment where the pH is about 7.0, most of the hydrogen atoms of the phenolic hydroxyl group of EGCg are converted to sodium. It is replaced, that is, the astringency-relieving effect is obtained, but when it is placed in an acidic environment such as the stomach, most of the phenolic hydroxyl groups are restored, that is, the state where the polyphenol's original physiological activity is exerted is restored. I understand that it will be done.

[0055]

Since the polyphenol salt of the present invention is a sodium salt, calcium salt, magnesium salt or potassium salt of polyphenol, it has a reduced astringency and the like and can be ingested in a large amount and has an acidity in the stomach. Since it returns to the original polyphenol below, it is expected to have a high physiological activity effect by a large intake, and since the polyphenol salt has improved water solubility compared to polyphenol, turbidity and precipitates will occur when made into an aqueous solution. It has the effect of being difficult.

Since the food of the present invention contains a polyphenol salt obtained by neutralizing polyphenol with an alkali, astringency and the like are reduced, and a large amount of the polyphenol salt contained in the food can be ingested. Moreover, since it returns to the original polyphenol under acidic conditions in the stomach, there is an effect that a high physiological activity effect can be expected by a large intake.

In the beverage of the present invention, since the polyphenol-containing extract is neutralized with an alkali, the astringency and the like are reduced, and a large amount of polyphenol salt can be ingested. Since it returns to the polyphenol, it has the effect that a high physiological activity effect can be expected by a large intake.

[Brief description of drawings]

FIG. 1 is a peak height around a wavelength of 273 nm in the UV absorption spectrum of an EGCg aqueous solution and p of the EGCg aqueous solution.
It is a graph showing the relationship with H.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // A21D 13/08 A23L 2/00 F 4C062 (72) Inventor Yasushi Furukawa 1-3, Itokaichi, Ibaraki, Osaka No. 30 Nagaoka Fragrance Co., Ltd. Technology Development Laboratory (72) Inventor Hiroaki Takeuchi 1-3-30 Gokaichi, Ibaraki, Osaka Prefecture Nagaoka Fragrance Co., Ltd. Technical Development Laboratory F-term (reference) 4B017 LC02 LC03 LG14 LK01 LK06 LL09 LP01 4B018 LB01 LB08 MD02 MD03 MD04 MD08 MD59 MD60 ME04 ME06 ME07 ME09 MF01 MF06 4B027 FB01 FB10 FC02 FC06 FK01 FK02 FK09 FP72 FP74 4B032 DB21 DK01 DK05 DK29 DL06 LG21 LG90LF22 LG31 LG02 LG22 LG04 LG04 LG22 LG04 LG22

Claims (7)

[Claims] 1. A polyphenol salt which is a sodium salt, calcium salt, magnesium salt or potassium salt of polyphenol. 2. A food containing the polyphenol salt according to claim 1. 3. A food product comprising an extract of a polyphenol-containing plant neutralized with an alkali selected from the group consisting of sodium hydroxide, calcium hydroxide, magnesium hydroxide and potassium hydroxide. 4. The food according to claim 2 or 3, which is a beverage, baked goods, gum, candy, chocolate, gummy, jelly, dairy product, instant noodles, ice cream, frozen dessert or bread. 5. A beverage obtained by neutralizing an extract of tea leaves containing polyphenol with an alkali selected from the group consisting of sodium hydroxide, calcium hydroxide, magnesium hydroxide and potassium hydroxide. 6. Astringency, bitterness or astringency of polyphenol, characterized by reacting polyphenol with an alkali selected from the group consisting of sodium hydroxide, calcium hydroxide, magnesium hydroxide and potassium hydroxide to form a polyphenol salt. How to reduce taste. 7. An astringent a polyphenol-containing extract, characterized in that the extract of a polyphenol-containing plant is neutralized with an alkali selected from the group consisting of sodium hydroxide, calcium hydroxide, magnesium hydroxide and potassium hydroxide. How to reduce taste, bitterness or astringency.