JP7768487B2 - Packaged soy-based beverages - Google Patents

Description

The present invention relates to a packaged soybean-based beverage and a method for producing the same. The present invention also relates to a method for reducing the bitterness of a bacteriostatic emulsifier contained in a packaged soybean-based beverage.

Soy milk is a milky beverage made by soaking soybeans in water, mashing them, heating them, and filtering them. Soy milk contains soybean-derived substances such as lecithin, saponin, isoflavones, and soy protein. Lecithin is known to maintain normal cell function and stimulate metabolism. Saponin also has antioxidant properties, suppressing the free radicals that cause skin aging. Lecithin also contains phosphatidylserine, which forms the membranes of brain nerve cells and is thought to help maintain memory. For this reason, the health benefits of soy milk beverages have been attracting attention in recent years.

Recently, soy milk beverages containing various ingredients and materials, as well as a variety of beverages containing soybean-derived components, have been developed. For example, Patent Document 1 proposes a fermented soy milk beverage containing vegetable juice and fruit juice with a reduced grassy smell, while Patent Document 2 proposes a beverage containing reconstituted juice of dried fruit and soy milk.

JP 2008-43280 A Japanese Patent Application Laid-Open No. 2018-139499

When the inventors developed a packaged soy milk-containing beverage and added a bacteriostatic emulsifier as an ingredient, they discovered that the resulting beverage had a bitter taste due to the emulsifier. Furthermore, while conducting extensive research into reducing the bitterness caused by bacteriostatic emulsifiers in soy milk-containing beverages, they discovered that the bitterness caused by bacteriostatic emulsifiers can be reduced by adjusting the viscosity and LST value of the soy milk-containing beverage within a certain range, without using additives such as masking agents. The present invention is based on these findings.

The present invention aims to provide a packaged soybean-containing beverage with a more natural taste and a method for producing the same. The present invention also aims to provide a method for reducing the bitterness caused by bacteriostatic emulsifiers in packaged soybean-containing beverages.

According to the present invention, the following inventions are provided.
[1] A packaged soybean-based beverage containing a bacteriostatic emulsifier, in which the viscosity (20°C) at a shear rate of 96 (1/s) and the LST (Line Spread Test) value (5°C) satisfy the following relationship (A): -0.071X + 36.353≦Y≦-0.071X + 48.353 (wherein X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (5°C), and X is in the range of 18≦X≦250).
[2] The beverage according to [1] above, wherein the content of the bacteriostatic emulsifier in the beverage is 0.0001 to 1%. [3] The beverage according to any one of [1] to [3] above, which is formulated with a thickening component.
[4] The beverage according to any one of [1] to [3] above, wherein the protein concentration in the beverage is 0.5 to 5.5% by mass.
[5] The beverage according to any one of [1] to [4] above, which is a beverage for distribution at room temperature.
[6] The beverage according to any one of [1] to [5] above, which is a retort sterilized beverage.
[7] A method for producing a packaged soybean-based beverage, comprising the steps of: blending a bacteriostatic emulsifier; and adjusting the viscosity (20°C) and LST value (5°C) of the beverage at a shear rate of 96 (1/s) so that the viscosity and LST value satisfy the following relationship (A): -0.071X + 36.353≦Y≦-0.071X + 48.353 (wherein X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (5°C), and X is in the range of 18≦X≦250).
[8] A method for reducing the bitterness of a packaged soybean-based beverage containing a bacteriostatic emulsifier, comprising adjusting the viscosity (20°C) and LST value (5°C) of the beverage at a shear rate of 96 (1/s) so that the viscosity and LST value satisfy the following relationship (A): -0.071X + 36.353≦Y≦-0.071X + 48.353 (wherein X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (5°C), and X is in the range of 18≦X≦250).

The packaged soybean-based beverage of the present invention is advantageous in that, even though it contains a bacteriostatic emulsifier as one of its ingredients, the bitterness inherent to the bacteriostatic emulsifier is reduced, resulting in a more natural taste and ease of drinking. Furthermore, although the bitterness of the packaged soybean-based beverage of the present invention tends to increase during the sterilization process, it is also advantageous in that the increase in bitterness caused by the sterilization process can be suppressed.

Specific Description of the Invention

In the present invention, the term "soy component-containing beverage" refers to a beverage containing soybean-derived ingredients, i.e., a beverage that uses soybeans as an ingredient, and is intended to include soy milk-containing beverages and soy beverages. Here, "soy milk-containing beverage" refers to a beverage that uses soy milk as an ingredient, and is intended to include soy milk and prepared soy milk specified by the Japanese Agricultural Standards, as well as soft drinks, fruit juice beverages, coffee beverages, and black tea beverages that contain soy milk. The soy milk used is not particularly limited as long as it is made from soybeans or processed soybeans (e.g., defatted processed soybeans), and examples that can be used include unadjusted soy milk, prepared soy milk, prepared powdered soy milk, and prepared defatted soy milk. Furthermore, the term "soy beverage" refers to a beverage that uses soybeans and/or soy flour as an ingredient, and is intended to include soft drinks, fruit juice beverages, coffee beverages, and black tea beverages that contain soybeans and/or soy flour.

The content of soy-derived components in the soy component-containing beverage of the present invention can be determined as desired. For example, the lower limit of the content of soy-derived components in the soy-containing beverage of the present invention can be 1% by mass (preferably 2% by mass, more preferably 3% by mass) of the total beverage as soy solids, and the upper limit of this content can be 15% by mass (preferably 10% by mass, more preferably 8% by mass or 7% by mass) of the total beverage as soy solids. These lower and upper limits can be combined as desired, and the content range can be, for example, 1 to 15% by mass, 2 to 10% by mass, or 3 to 7% by mass. Note that, in the present invention, "solids" refers to components excluding water.

The protein concentration in the soybean component-containing beverage of the present invention can be 0.5 to 5.5% by mass, and preferably 0.7 to 5% by mass. The protein concentration in the beverage can be measured using a combustion method or the like.

The soybean-containing beverage of the present invention comprises a bacteriostatic emulsifier. Here, "bacteriostatic emulsifier" refers to a food emulsifier that has the effect of inhibiting the germination and growth of heat-resistant spore-forming bacteria in a beverage. Examples of bacteriostatic emulsifiers that can be used in the present invention include one or more selected from the group consisting of sucrose fatty acid esters, glycerin fatty acid esters (including polyglycerin fatty acid esters and monoglycerin fatty acid esters), and organic acid monoglycerides. The content of the bacteriostatic emulsifier in the beverage can be, for example, 0.0001 to 1% (preferably 0.0005 to 0.8%, more preferably 0.001 to 0.8%, even more preferably 0.01 to 0.8%, and even more preferably 0.01 to 0.6%). The bacteriostatic emulsifier in the beverage can have a lower limit HLB value of 1 or more (preferably 2 or more, more preferably 3 or more), and an upper limit HLB value of 19 or less (preferably 18 or less, more preferably 17 or less). The HLB value range can be, for example, 1 to 19, 2 to 18, or 3 to 17.

Examples of the sucrose fatty acid ester include sucrose fatty acid esters whose constituent fatty acids are one or a combination of two or more substances selected from the group consisting of saturated or unsaturated fatty acids having 2 to 22 carbon atoms, such as acetic acid, propionic acid, butyric acid, isobutyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, and oleic acid. Among these, sucrose fatty acid esters whose constituent fatty acids are one or a combination of two or more substances selected from the group consisting of saturated fatty acids having 2 to 18 carbon atoms are preferred. Furthermore, sucrose fatty acid esters whose constituent fatty acids are 50% by weight or more (preferably 70% by weight or more) of one or a combination of two or more substances selected from the group consisting of palmitic acid, stearic acid, isobutyric acid, and acetic acid are even more preferred, and sucrose fatty acid esters whose constituent fatty acids are 50% by weight or more (preferably 70% by weight or more) of palmitic acid are even more preferred.

More preferably, the sucrose fatty acid ester is a sucrose fatty acid ester (sucrose palmitate ester) in which the constituent fatty acid is palmitic acid. In this specification, "constituent fatty acid" also includes, for convenience, carboxylic acids such as isobutyric acid and acetic acid in addition to fatty acids.

The above-mentioned polyglycerol fatty acid esters include polyglycerol fatty acid esters in which the average degree of polymerization of the polyglycerol is 2 to 20 (preferably 3 to 10), polyglycerol fatty acid esters in which the constituent fatty acids are one or a combination of two or more substances selected from the group consisting of saturated or unsaturated fatty acids having 2 to 22 carbon atoms, and polyglycerol fatty acid esters in which 50% by weight or more (preferably 70% by weight or more) of the constituent fatty acids are a combination of one or two substances selected from the group consisting of lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid. Preferred polyglycerol fatty acid esters include polyglycerol fatty acid esters in which the average degree of polymerization of polyglycerol is 2 to 20 (preferably 3 to 10) and the constituent fatty acids are one or a combination of two or more substances selected from the group consisting of saturated or unsaturated fatty acids having 2 to 22 carbon atoms, as described above, and polyglycerol fatty acid esters in which the average degree of polymerization of polyglycerol is 2 to 20 (preferably 3 to 10) and 50% by weight or more (preferably 70% by weight or more) of the constituent fatty acids are one selected from the group consisting of lauric acid, myristic acid, palmitic acid, stearic acid and oleic acid. or a polyglycerol fatty acid ester that is a combination of two or more substances, and more preferred polyglycerol fatty acid esters include polyglycerols having an average degree of polymerization of 2 to 20 (preferably 3 to 10), whose constituent fatty acids are saturated or unsaturated fatty acids having 2 to 22 carbon atoms as described above, and in which 50% by weight or more (preferably 70% by weight or more) of the constituent fatty acids are one or a combination of two or more substances selected from the group consisting of lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid. Furthermore, preferred polyglycerol fatty acid esters include polyglycerol fatty acid esters in which 50% by weight or more (preferably 70% by weight or more) of the constituent fatty acids are palmitic acid, and even more preferred are polyglycerol fatty acid esters in which the average degree of polymerization of the polyglycerol is 2 to 20 (preferably 3 to 10). Furthermore, polyglycerol fatty acid esters are more preferably polyglycerol fatty acid esters whose constituent fatty acid is palmitic acid (polyglycerol palmitate esters), and even more preferably polyglycerol fatty acid esters whose polyglycerin has an average degree of polymerization of 2 to 20 (preferably 3 to 10).

Preferred examples of the monoglycerin fatty acid ester include monoglycerin fatty acid esters whose constituent fatty acids are one or a combination of two or more substances selected from the group consisting of saturated or unsaturated fatty acids having 2 to 22 carbon atoms, and monoglycerin fatty acid esters whose constituent fatty acids are one or a combination of two or more substances selected from the group consisting of lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid at 50% by weight or more (preferably 70% by weight or more). Preferred examples of the monoglycerin fatty acid ester include monoglycerin fatty acid monoesters and monoglycerin fatty acid diesters. Preferred examples of the monoglycerin fatty acid ester include monoglycerin fatty acid esters whose constituent fatty acids are 50% by weight or more (preferably 70% by weight or more) palmitic acid, and even more preferred examples of the monoglycerin fatty acid esters whose constituent fatty acid is palmitic acid (monoglycerin palmitate esters).

The soybean component-containing beverage of the present invention can contain at least a thickening component as an ingredient. Here, the term "thickening component" refers to a component that has a thickening effect and is acceptable as a food. It may be a food or a food additive, and is used to mean thickening polysaccharides, thickening stabilizers, stabilizers, thickeners, pastes, and gelling agents. Examples of thickening components include carrageenan, gellan gum, agar, glucomannan, gelatin, curdlan, gelatin, gum arabic, guar gum, gum ghatti, modified starch, and pectin. The amount of thickening component in the soybean component-containing beverage of the present invention can be adjusted so that the viscosity and LST value fall within the specified ranges described below. For example, the amount of carrageenan, calculated as solids, relative to the total beverage can be 0.06 to 0.7% by mass (preferably 0.1 to 0.7% by mass, more preferably 0.15 to 0.5% by mass), gellan gum can be 0.07 to 0.3% by mass (preferably 0.1 to 0.15% by mass), and agar can be 0.1 to 0.5% by mass (preferably 0.17 to 0.22% by mass). The amount of thickener can be adjusted appropriately based on the amount of soybean solids and the amount of emulsifier, etc.

The soybean component-containing beverage of the present invention can also contain seasonings as raw materials. Examples of seasonings include sugars and sugar-containing food ingredients, salt, and umami seasonings. Specific examples of sugars and sugar-containing food ingredients include sugar, glucose-fructose syrup, fructose-glucose syrup, high-fructose syrup, sugar-mixed glucose-fructose syrup, sugar-mixed fructose-glucose syrup, sugar-mixed high-fructose syrup, glucose, starch syrup, lactose, maltose, honey, and brown sugar. The content of seasonings in the soybean component-containing beverage of the present invention can be 0.1 to 15% by mass (preferably 0.5 to 10% by mass) of the total beverage, calculated on a solids basis.

The soybean component-containing beverage of the present invention can further contain a flavoring ingredient as a raw material in addition to the thickening ingredient. Examples of flavoring ingredients include fruit juice, vegetable juice, fruit pulp, coffee, tea, cocoa, milk, milk powder, grain powder, matcha green tea, kelp powder, soybean flour, dried plant powder and extract concentrate, and dairy products such as yogurt.

The soybean component-containing beverage of the present invention may contain, in addition to the above, ingredients and materials that are acceptable as foods. Such ingredients and materials are not particularly limited as long as the soybean component-containing beverage of the present invention satisfies the relationship (A) described in [1] above, and examples include edible vegetable oils and fats, antifoaming agents, pH adjusters, quality improvers, acidulants, sweeteners, coloring agents, and flavorings. In the soybean component-containing beverage of the present invention, the bitterness derived from the bacteriostatic emulsifier can be reduced without the incorporation of a bitterness-masking component, but this does not preclude the incorporation of ingredients and materials that reduce the bitterness derived from the bacteriostatic emulsifier.

The soybean component-containing beverage of the present invention also has a viscosity (20°C) at a shear rate of 96 (1/s) and an LST value (5°C) that satisfy the following relationship (A):
-0.071X+36.353≦Y≦-0.071X+48.353;
Preferably, the following relational expression (B) is satisfied: −0.071X+39.353≦Y≦−0.071X+45.353
(In the above formula, X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (5°C), and X is in the range of 18≦X≦250.)
The formulas (A) and (B) are derived by calculating the correlation equation: Y = -0.071X + 42.353 (R ² = 0.8361) by the least squares method based on the viscosities and LST values of the beverages in test plots 4 to 10, 12 to 16, 22, 23, 27, 28, 31, 32, 36, 47 to 54, and 60 to 63, in which the effects of the present invention were confirmed in the Examples described below, and then increasing or decreasing the intercept (42.353) of formula (A) by ±6 and by ±3, respectively, while maintaining the slope (-0.071) of the correlation equation, so as to include the beverages in the test plots in which the effects of the present invention were confirmed in the Examples described below. According to the present invention, the bitterness derived from the bacteriostatic emulsifier can be reduced by adjusting the viscosity and LST value of the beverage to fall within these numerical ranges. The incorporation of a bacteriostatic emulsifier can improve the stability of a beverage over time and reduce microbial risk, but the soy component-containing beverage of the present invention is advantageous in that it achieves these goals while reducing the bitterness derived from the bacteriostatic emulsifier without the incorporation of a bitterness-masking component. Furthermore, while the bitterness derived from the bacteriostatic emulsifier tends to be enhanced during the sterilization process, the beverage of the present invention is also advantageous in that it can suppress the enhancement of bitterness due to the sterilization process. The viscosity is preferably 60 to 250 mPa·s, more preferably 90 to 166 mPa·s. The LST value is preferably 25 to 37 mm, more preferably 28 to 35 mm, and even more preferably 30 to 35 mm.

In the soybean component-containing beverage of the present invention, the viscosity (20°C) and LST value (5°C) at a shear rate of 96 (1/s) can be adjusted to fall within a specified range by adjusting the protein concentration in the beverage and incorporating thickening ingredients into the beverage, as described in the examples below.

The soybean ingredient-containing beverage of the present invention further has a viscosity (20°C) at a shear rate of 96 (1/s) and an LST value (5°C) that satisfy the following relationship (C):
-0.0733X+36.686≦Y≦-0.0733X+48.686;
Preferably, the following relational expression (D) is satisfied: −0.0733X+39.686≦Y≦−0.0733X+45.686
(In the above formula, X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (5°C), and X is in the range of 18≦X≦250.)
The above formulas (C) and (D) can be derived by calculating the correlation equation: Y = -0.0733X + 42.686 (R ² = 0.8063) by the least squares method based on the viscosity and LST values of the beverages in test plots 4 to 10, 12 to 16, 22, and 23, in which the effects of the present invention were confirmed in the Examples described below. Then, using this correlation equation as the center, while maintaining the slope of the correlation equation (-0.0733), the intercept (42.686) of formula (C) can be increased or decreased by ±6, and the intercept (42.686) of formula (D) can be increased or decreased by ±3, so as to include the beverages in the test plots in which the effects of the present invention were confirmed in the Examples described below. The soybean component-containing beverage can have a soybean solids content of 2 to 8%, preferably 4 to 6%. The bacteriostatic emulsifier contained in the soybean component-containing beverage can have an HLB value of 14 to 18, preferably 15 to 17.

The soybean ingredient-containing beverage of the present invention can be one in which the viscosity (20°C) at a shear rate of 96 (1/s) and the LST value (5°C) satisfy the following relationship:
When carrageenan was used as a thickener: −0.0751X+40.396≦Y≦−0.0751X+46.396 (18≦X≦250) (R ² =0.8832)
When agar is used as the thickener: −0.0267x+31.753≦y≦−0.0267x+37.753 (60≦X≦100) (R ² =1)
When gellan gum was used as the thickener: −0.1109X+42.786≦Y≦−0.1109X+48.786 (20≦X≦100) (R ² =0.9558)
(In the above formula, X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), and Y represents the LST value (5°C).) These formulas are derived based on the viscosity and LST values of the beverages in the test plots in which the effects of the present invention were confirmed in the Examples described below. Specifically, a correlation equation was calculated by the least squares method based on the viscosity and LST values of the beverages in test plots 4 to 10, 27, 28, 31, 32, and 36 in the case of using carrageenan, the beverages in test plots 22 and 23 in the case of using agar, and the beverages in test plots 12 to 16 in the case of using gellan gum. The correlation equation was then derived by increasing or decreasing the intercept by ±3 while maintaining the slope of each of the above relational equations, centered on the correlation equation, so as to include the beverages in the test plots in which the effects of the present invention were confirmed in the Examples described below. The soybean component-containing beverage described above may have a soybean solids content of 2 to 8%, preferably 4 to 6%.

The viscosity of the soybean component-containing beverage of the present invention can be measured using a measuring device (rotational viscometer) capable of measuring viscosity at a predetermined shear rate, for example, as described in Example 1 (3) A.

The LST value of the soy component-containing beverage of the present invention can be measured by a line spread test (sometimes simply referred to as "LST" herein). The LST value can be measured, for example, according to the method described in "2013 Swallowing-Adjusted Diet Classification of the Japanese Society of Eating and Swallowing Rehabilitation," Journal of the Japanese Society of Eating and Swallowing Rehabilitation, 17(3):255-267 (2013). The LST value is an index of the thickness of the food being analyzed; the smaller this value, the thicker the beverage.

The pH of the soybean component-containing beverage of the present invention can be adjusted to a neutral range (e.g., pH 5 to 9, preferably pH 6 to 8). pH adjustment can be carried out using a pH adjuster such as sodium bicarbonate.

The soybean component-containing beverage of the present invention can be provided in the form of a packaged beverage. The container may be any type of container, such as a paper carton, a plastic bottle, a steel can, an aluminum can, a glass bottle, a pouch, or a cup.

In the present invention, the packaged soy component-containing beverage may be sterilized in a retort or pasteurizer, or the sterilized soy component-containing beverage may be aseptically filled or hot-packed into the container. Packaging and sterilization can be carried out according to conventional methods.

The soy component-containing beverage of the present invention can be produced according to standard procedures for producing soy component-containing beverages, except for adjusting the viscosity and LST value to within a predetermined range. In the present invention, for example, raw materials containing soy components are prepared and mixed, and optional steps such as pH adjustment, filtration, homogenization, and cooling may be carried out to produce a soy component-containing beverage of the present invention that has been adjusted to a predetermined viscosity and LST value. Among the raw materials, soy components can be soy milk, which may be liquid or powder, or a combination of these. There are no limitations on the timing of adding the bacteriostatic emulsifier to the raw materials, but it is preferable to add it when the raw materials containing soy components are being mixed.

According to another aspect of the present invention, there is provided a method for producing a packaged soybean-based beverage containing a bacteriostatic emulsifier, the method comprising the steps of: blending the bacteriostatic emulsifier; and determining whether the viscosity (20°C) and LST value (5°C) of the beverage at a shear rate of 96 (1/s) satisfy the following relationship:
-0.071X+36.353≦Y≦-0.071X+48.353
(In the above formula, X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (5°C), and X is in the range of 18≦X≦250.)
and adjusting the viscosity and LST value so that the above-mentioned formula (1) and (2) are satisfied. The production method of the present invention can be carried out in accordance with the description of the soy component-containing beverage of the present invention.

According to yet another aspect of the present invention, there is provided a method for reducing bitterness in a packaged soybean-based beverage containing a bacteriostatic emulsifier, the method comprising the steps of: (a) determining whether the viscosity (20°C) of the beverage at a shear rate of 96 (1/s) and the LST value (5°C) satisfy the following relationship:
-0.071X+36.353≦Y≦-0.071X+48.353
(In the above formula, X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (5°C), and X is in the range of 18≦X≦250.)
The bitterness reducing method of the present invention can be carried out in accordance with the description of the soy component-containing beverage of the present invention.

The present invention will be explained in more detail based on the following examples, but the present invention is not limited to these examples.

Example 1: Examination of the effect of reducing bitterness in soy milk-containing beverages (1)
In Example 1, the bitterness-reducing effect was examined for a soy milk-containing beverage to which sucrose palmitate was added as a bacteriostatic emulsifier (hereinafter sometimes simply referred to as "emulsifier").

(1) Preparation of Test Beverages Raw materials were prepared in the amounts shown in Table 1, and emulsifiers and thickeners were subjected to appropriate dissolution or swelling treatments, followed by addition of the types and addition rates shown in Tables 2 to 5. Ion-exchanged water was then added to the mixture of raw materials obtained as described above to obtain a total of 1 kg of prepared liquid. The amount of soybean-derived protein (hereinafter sometimes referred to as "soybean-derived protein") contained in 100 g of prepared liquid was 2.4 g (5% soybean solids). The obtained prepared liquid was filled into glass bottles for beverage samples and then sterilized at 121°C for 20 minutes using a retort sterilizer to obtain packaged soy milk-containing beverages (Test Groups 1 to 20). In Examples 1 and 2, the liquid soy milk used was "Delicious Unsweetened Soy Milk (Soybean Solids 8%)" (Kikkoman), the powdered soy milk used was "IM-100 (Soybean Solids 100%)" (Imuraya), and the emulsifier used was sucrose palmitate (Ryoto Sugar Ester P-1670, Mitsubishi Chemical Foods). Furthermore, the thickeners used were Carrageenan CS-396 (Sanei Gen F.F.I., Inc.), gellan gum Kelcogel HM (Sanei Gen F.F.I., Inc.), xanthan gum (Marugo Corporation), and agar powder (Ina Food Industry Co., Ltd.).

(2) Sensory Evaluation Sensory evaluation of the soy milk-containing beverages was carried out as follows.
A sensory evaluation test was conducted by a panel of four experts on the degree of bitterness suppression of each of the soy milk-containing beverages obtained in test plots 1 to 23. Furthermore, a sensory evaluation test was conducted by a panel of four experts on the drinkability of each of the soy milk-containing beverages in test plots 1 to 10. The degree of bitterness suppression of the soy milk-containing beverages in each test plot was evaluated according to the following criteria, with the soy milk-containing beverage in test plots 1 to 20 (Table 2) as the standard for test plots 1 to 20, and the soy milk-containing beverage in test plot 21 (Table 5) as the standard for test plots 21 to 23, and the degree of bitterness suppression of each of the soy milk-containing beverages in each test plot was evaluated according to the following criteria. Drinkability was evaluated according to the following criteria. In order to reduce the variation in the evaluations of each panel, each panel evaluated the degree of bitterness suppression and the degree of bitterness suppression of several types of soy milk-containing beverages whose drinking suitability was known, and then the evaluation scores were compared to confirm that there was no significant discrepancy in the evaluation criteria of each panel.It was also confirmed that the standard deviation of the evaluation scores of each panel was within 0.5.

Criteria for evaluating bitterness: Degree of bitterness suppression: 4 points: Very suppressed; 3 points: Highly suppressed; 2 points: Suppressed; 1 point: Slightly suppressed; 0 point: Not suppressed

Drinkability 3 points: Very easy to swallow, very easy to drink 2 points: Easy to swallow, easy to drink 1 point: Slightly difficult to swallow, but does not affect drinkability 0 point: Difficult to swallow, difficult to drink

The degree of bitterness suppression and drinkability of each soy milk-containing beverage were determined by calculating the average score of the four expert panel members. The soy milk-containing beverage was then rated based on the average score: 0-1 points = ×, 1-2 points = △, 2-3 points = ○, and 3-4 points = ◎. If the score was an integer, the result was treated as the highest ranking. (For example, if the average score was exactly 1 point, it was marked as △ instead of ×.)

(3) Instrumental Evaluation Instrumental evaluation of the soy milk-containing beverage was carried out as follows.
A. Viscosity The viscosity of the beverage obtained in (1) above was measured using a precision rotational viscometer (RST-CC, Brookfield). Measurements were performed using a double cylindrical spindle CCT-DG. The measurement conditions were shear rate 0.1 (1/s) to 2000 (1/s), measurement temperature: 20°C, liquid volume: 15.7 mL, shear rate control (log) for a measurement time of 250 seconds, and 50 measurement points. The viscosity was measured at a shear rate of 96 (1/s).

(i) LST Value: The degree of viscosity of the beverage obtained in (1) above was evaluated. A line spread test was performed using a "Thickness Measuring Plate" (Saraya) at a measurement temperature of 5°C to determine the LST value (mm) (see "2013 Swallowing-Adjusted Diet Classification of the Japanese Society of Eating and Swallowing Rehabilitation," Journal of the Japanese Society of Eating and Swallowing Rehabilitation, 17(3):255-267(2013)). Specifically, the procedure was as follows: First, using a graduated sheet, 20 mL of the solution to be measured was placed in a 30 mm diameter ring. After injecting the solution into the ring, a 30-second wait was held to stop the liquid flow within the ring. The ring was then lifted, and the spread of the solution was measured after 30 seconds. The sheet is graduated in six directions, and the values at these six points were read and the average value was calculated. Since this evaluation measures the spread of the liquid, measurements were taken on a horizontal surface.

(4) Results The results of the sensory evaluation and instrumental evaluation are shown in Tables 2 to 5.

These results confirmed that in soybean-based beverages containing emulsifiers, the bitterness derived from the emulsifier can be reduced when the viscosity (20°C) at a shear rate of 96 m/s and the LST value (5°C) satisfy the following relationship: -0.071X + 36.353≦Y≦-0.071X + 48.353 (where X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (5°C), and the range of X is 18≦X≦250).

Example 2: Examination of the effect of reducing bitterness in soy milk-containing beverages (2)
In Example 2, the bitterness-reducing effect of a soy milk-containing beverage to which a bacteriostatic emulsifier different from that in Example 1 was added was examined.

(1) Preparation of Test Beverages Test beverages (Test Plots 24 to 36) were prepared according to the procedure described in Example 1(1), except for using the emulsifiers and thickeners shown in Tables 6 to 8. The emulsifiers used were triglycerin palmitate (TRP-97RF, Riken Vitamin), succinic acid fatty acid monoglyceride (Poem B-10, Riken Vitamin), and polyglycerin fatty acid ester (DP-95RF, Riken Vitamin).

(2) Sensory Evaluation The sensory evaluation of the soy milk-containing beverages was carried out according to the criteria and procedures described in Example 1(2), except that the degree of bitterness suppression was evaluated when each thickener was added, with the soy milk-containing beverage of test plot 24 (Table 6) as the standard for test plots 24 to 28, the soy milk-containing beverage of test plot 29 (Table 7) as the standard for test plots 29 to 32, and the soy milk-containing beverage of test plot 33 (Table 8) as the standard for test plots 33 to 36.

(3) Instrumental Evaluation Instrumental evaluation of the soy milk-containing beverage was carried out according to the procedure described in Example 1(3).

(4) Results The results of the sensory evaluation and instrumental evaluation are shown in Tables 6 to 8.

These results confirmed that even when a different emulsifier than that used in Example 1 is used, the bitterness derived from the emulsifier can be reduced in soybean component-containing beverages containing an emulsifier when the viscosity (20°C) at a shear rate of 96 m/s and the LST value (5°C) satisfy the following relationship: -0.071X + 36.353≦Y≦-0.071X + 48.353 (where X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (5°C), and the range of X is 18≦X≦250).

Example 3: Examination of the effect of reducing bitterness in soy milk-containing beverages (3)
In Example 3, the effect of adding multiple types of thickeners to reduce the bitterness of a soy milk-containing beverage was investigated.

(1) Preparation of Test Beverages Test beverages (test plots 37 to 43) were prepared according to the procedure described in Example 1(1), except that the multiple types of thickeners shown in Table 9 were used.
(2) Sensory Evaluation The sensory evaluation of the soy milk-containing beverages was carried out in accordance with the standards and procedures described in Example 1(2), except that the degree of bitterness suppression was evaluated for test plots 37 to 43 when each thickener was added, with the soy milk-containing beverage of test plot 1 (Table 2) as the standard.

(3) Instrumental Evaluation Instrumental evaluation of the soy milk-containing beverage was carried out according to the procedure described in Example 1(3).

(4) Results The results of the sensory evaluation and instrumental evaluation are shown in Table 9.

These results confirmed that even in soy milk-containing beverages containing multiple types of thickeners, the bitterness derived from the emulsifier can be reduced when the viscosity (20°C) at a shear rate of 96 m/s and the LST value (5°C) satisfy the following relationship: -0.071X + 36.353≦Y≦-0.071X + 48.353 (where X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (5°C), and the range of X is 18≦X≦250).

Example 4: Examination of the effect of reducing bitterness in soy milk-containing beverages (4)
In Example 4, the bitterness-reducing effect of a soy milk-containing beverage having a soybean solids content different from that of Example 1 was examined.

(1) Preparation of Test Beverages Test beverages (test plots 44 to 63) were prepared according to the procedure described in Example 1(1), except that raw materials were prepared in the blending amounts shown in Table 10 (soybean solids: 2%) and Table 11 (soybean solids: 8%), and bacteriostatic emulsifiers and thickeners were added in the types and addition rates shown in Tables 12 and 13 after appropriate dissolution or swelling treatment.

(2) Sensory Evaluation The sensory evaluation of the soy milk-containing beverages was carried out according to the criteria and procedures described in Example 1(2), except that the degree of bitterness suppression was evaluated when each thickener was added, with the soy milk-containing beverage of test plot 44 (Table 12) as the standard for test plots 44 to 54 and the soy milk-containing beverage of test plot 55 (Table 13) as the standard for test plots 55 to 63.

(3) Instrumental Evaluation Instrumental evaluation of the soy milk-containing beverage was carried out according to the procedure described in Example 1(3).

(4) Results The results of the sensory evaluation and instrumental evaluation are shown in Tables 12 and 13.

These results confirmed that even for soy milk-containing beverages with a different soy solids content than that of Example 1, the bitterness derived from the emulsifier can be reduced when the viscosity (20°C) at a shear rate of 96 m/s and the LST value (5°C) satisfy the following relationship: -0.071X + 36.353≦Y≦-0.071X + 48.353 (where X represents the viscosity (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (5°C), and the range of X is 18≦X≦250).

Example 5: Effect of sterilization on the bitterness of soy milk-containing beverages The effect of sterilization on the bitterness resulting from the bacteriostatic emulsifier contained in soy milk-containing beverages was compared under different sterilization conditions.

(1) Preparation of Test Beverages Test beverages (test plots 64 to 78) were prepared according to the procedure described in Example 1(1), except that the sterilization conditions were as shown in Tables 14 and 15 and no thickener was added.

(2) Sensory evaluation The sensory evaluation of the soy milk-containing beverages was carried out as follows. A sensory evaluation test was conducted by a panel of four experts on the level of bitterness of each of the soy milk-containing beverages obtained in test plots 64 to 78. The level of bitterness was evaluated by comparing the level of bitterness of the soy milk-containing beverage under sterilization conditions β and γ with the level of bitterness of the soy milk-containing beverage under sterilization condition α (no sterilization treatment) at each amount of emulsifier added.

(3) Results The results of the sensory evaluation were as follows. When P-1670 (test plots 64 to 69) and TRP-97R (test plots 70 to 78) were used as emulsifiers, it was confirmed that the bitterness was stronger under sterilization conditions β and γ than under sterilization condition α at any addition rate. In particular, there was a tendency for the bitterness to be stronger under sterilization condition β.

Claims (9)

The viscosity (mPa s) (20°C) at a shear rate of 96 (1/s) and the LST value (mm) (5°C) are expressed by the following relational expression (A):
-0.071X+36.353≦Y≦-0.071X+48.353
(wherein X represents the viscosity (mPa s) (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (mm) (5°C), and X is in the range of 60≦X≦166), and is a packaged soybean-based beverage containing a bacteriostatic emulsifier and a thickening component, the thickening component being one or more selected from the group consisting of carrageenan, gellan gum, and agar, the content of the bacteriostatic emulsifier being 0.0001 to 1%, and the bacteriostatic emulsifier being one or more selected from the group consisting of sucrose fatty acid esters, glycerin fatty acid esters, and organic acid monoglycerides . 2. The beverage according to claim 1, wherein the carrageenan content is 0.06 to 0.7% by mass, the gellan gum content is 0.07 to 0.3% by mass, and the agar content is 0.1 to 0.5% by mass. 3. The beverage according to claim 1 , wherein the protein concentration in the beverage is 0.5 to 5.5% by mass. The beverage according to any one of claims 1 to 3 , which is a beverage for distribution at room temperature. The beverage according to any one of claims 1 to 4 , which is a retort sterilized beverage. A method for producing a packaged soybean-based beverage, comprising the steps of: blending a bacteriostatic emulsifier and a thickening component; and determining whether the viscosity (mPa s) (20°C) of the beverage at a shear rate of 96 (1/s) and the LST value (mm) (5°C) satisfy the following relationship (A):
-0.071X+36.353≦Y≦-0.071X+48.353
(wherein X represents the viscosity (mPa s) (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (mm) (5°C), and X is in the range of 60≦X≦166), wherein the thickening component is one or more selected from the group consisting of carrageenan, gellan gum, and agar , the content of the bacteriostatic emulsifier is 0.0001 to 1%, and the bacteriostatic emulsifier is one or more selected from the group consisting of sucrose fatty acid esters, glycerin fatty acid esters, and organic acid monoglycerides . The manufacturing method according to claim 6, wherein the content of the carrageenan is 0.06 to 0.7% by mass, the content of the gellan gum is 0.07 to 0.3% by mass, and the content of the agar is 0.1 to 0.5% by mass. A method for reducing bitterness of a packaged soybean-based beverage containing a bacteriostatic emulsifier and a thickening component, wherein the viscosity (mPa s) (20°C) of the beverage at a shear rate of 96 (1/s) and the LST value (mm) (5°C) satisfy the following relationship (A):
-0.071X+36.353≦Y≦-0.071X+48.353
(wherein X represents the viscosity (mPa s) (20°C) of the beverage at a shear rate of 96 (1/s), Y represents the LST value (mm) (5°C), and X is in the range of 60≦X≦166) , wherein the thickening component is one or more selected from the group consisting of carrageenan, gellan gum, and agar, the content of the bacteriostatic emulsifier is 0.0001 to 1%, and the bacteriostatic emulsifier is one or more selected from the group consisting of sucrose fatty acid esters, glycerin fatty acid esters, and organic acid monoglycerides . The bitterness reduction method according to claim 8, wherein the carrageenan content is 0.06 to 0.7% by mass, the gellan gum content is 0.07 to 0.3% by mass, and the agar content is 0.1 to 0.5% by mass.