Heat-treated soybean raw material and foaming agent containing it as an active ingredient

Abstract

The purpose of the present invention is to provide a material which can impart excellent foaming properties, foam stability, and finely textured foam.　This heat-treated product is obtained by heat treating, under high-temperature acidic conditions, a soybean raw material in which the crude protein content, the carbohydrate content, and the lipid content has been adjusted. The heat-treated product is characterized in that: a specified fraction is present at a proportion that is equal to or more than a given quantity, said specified fraction having a weight-average molecular weight of 3000-15000 when the molecular weight distribution thereof is measured by gel filtration HPLC at a wavelength of 220 nm; and the rate of change in the foam size is no more than 10% when the rate of change in the foam size is measured by a dynamic foam analyzer. It was discovered that said heat-treated product imparts excellent foaming properties, foam stability, and finely textured foam to a beverage, etc.

Description

[Technical Field]

[0001] The present invention relates to a heat-treated soybean raw material and a foaming agent containing the same as an active ingredient. [Background technology]

[0002] Foaming ability and foam stability are important for aerated foods and beverages such as meringues and shake drinks, and methods for improving foaming ability and foam stability have been investigated. For example, a technique using water-soluble hemicellulose as a foaming agent (Patent Document 1), a technique using it in combination with a foaming agent such as cyclodextrin or soy peptide (Patent Document 2), and a technique using water-soluble soy polysaccharides as a foam stabilizer in sparkling drinks (Patent Document 3) have been proposed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-244880 [Patent Document 2] Japanese Unexamined Patent Publication No. 49-102870 [Patent Document 3] WO2008 / 069027 publication Summary of the Invention [Problem to be solved by the invention]

[0004] Foods and beverages that require foaming properties are required to have good foaming properties and foam stability, but the technologies of Patent Documents 1 to 3 are not necessarily sufficient and there is room for improvement. Therefore, currently, in order to impart better foaming properties and foam stability, it is necessary to separately produce a foaming agent such as soy peptides as shown in Patent Document 2 and a foam stabilizer such as water-soluble soy polysaccharides as shown in Patent Documents 1 and 3 and combine them, but this is not efficient in terms of cost and work. Therefore, if a single material could be used to impart a sufficiently good foaming agent and foam stabilizer, it would be advantageous in terms of cost and work. Furthermore, in recent years, in addition to foaming ability and bubble stability, foods and beverages that require foaming properties are increasingly being required to produce fine bubbles for reasons such as a pleasant mouthfeel, and materials that can also impart fine bubbles are also in demand. Therefore, an object of the present invention is to provide a material that can impart good foaming properties, foam stability, and fine bubbles. [Means for solving the problem]

[0005] The present inventors conducted extensive research to solve the above problems. As a result, they discovered that a heat-treated product obtained by heat-treating a soybean raw material with adjusted crude protein, sugar, and lipid contents under high-temperature acidic conditions contains a specific fraction with a weight-average molecular weight of 3,000 to 15,000 in a proportion greater than or equal to a certain amount when its molecular weight distribution is measured by gel filtration HPLC at a wavelength of 220 nm, and that when the rate of change in bubble size is measured by a dynamic foam analyzer, the rate of change in bubble size is 10% or less, and that this imparts good foaming properties, bubble stability, and fine bubble texture to beverages and the like, leading to the completion of the present invention.

[0006] That is, the present invention provides: (1) A heat-treated soybean raw material having the following A) to C): A) The crude protein content, calculated on a dry matter basis, is 14 to 35% by weight, the carbohydrate content is 55 to 85% by weight, and the lipid content is 1% by weight or less. B) In the molecular weight distribution at a wavelength of 220 nm measured by gel filtration HPLC, the ratio of the peak area of ​​the peptide region fraction with a weight-average molecular weight of 3,000 to 15,000 to the total peak area is 40% or more. C) When a 0.3 wt% aqueous solution is used and the rate of change in bubble size is measured using a dynamic foam analyzer, the rate of change in bubble size calculated using the following formula is 10% or less. Rate of change in bubble size (%) = {bubble size after 5 minutes of bubble generation (μm 2 ) - bubble size immediately after bubble generation (μm 2 )}÷bubble size immediately after generation (μm 2 ) x 100 (2) A foaming agent containing the heat-treated soybean raw material according to (1) as an active ingredient. (3) A method for producing a heat-treated soybean raw material comprising the following A) to C), characterized in that a soybean-derived raw material having a crude protein content of 28 to 55% by weight, a sugar content of 35 to 62% by weight, and a lipid content of 5% or less by weight, calculated on a dry matter basis, is heated under conditions of more than 100°C and not more than 160°C, and a pH of more than 4 and not more than 6, to obtain a slurry, and the slurry is subjected to solid-liquid separation to obtain a filtrate having a crude protein content of 14 to 35% by weight, a sugar content of 55 to 85% by weight, and a lipid content of 1% or less by weight, calculated on a dry matter basis; A) The crude protein content, calculated on a dry matter basis, is 14 to 35% by weight, the carbohydrate content is 55 to 85% by weight, and the lipid content is 1% by weight or less. B) In the molecular weight distribution at a wavelength of 220 nm measured by gel filtration HPLC, the ratio of the peak area of ​​the peptide region fraction having a weight-average molecular weight of 3,000 to 15,000 to the total peak area is 40% or more; C) When a 0.3 wt% aqueous solution is used and the rate of change in bubble size is measured using a dynamic foam analyzer, the rate of change in bubble size calculated using the following formula is 10% or less. Rate of change in bubble size (%) = {bubble size after 5 minutes of bubble generation (μm 2 ) - bubble size immediately after bubble generation (μm 2 )}÷bubble size immediately after generation (μm 2 ) × 100, is. [Effects of the Invention]

[0007] By adding the heat-treated product of the present invention to food or drink, it is possible to impart excellent foaming properties, foam stability, and fine bubbles to the food or drink. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 shows the molecular weights of heat-treated products A to B when their molecular weight distributions are measured by gel filtration HPLC at a wavelength of 220 nm. [Figure 2] FIG. 10 is a diagram showing the molecular weights of heat-treated products C to D when their molecular weight distributions are measured by gel filtration HPLC at a wavelength of 220 nm. [Figure 3]FIG. 1 shows the molecular weight distribution of heat-treated product E measured by gel filtration HPLC at a wavelength of 220 nm. [Figure 4] FIG. 1 shows the molecular weight distribution of heat-treated product F measured by gel filtration HPLC at a wavelength of 220 nm. [Figure 5] FIG. 10 is a diagram showing the molecular weights of heat-treated products G to H when their molecular weight distributions are measured by gel filtration HPLC at a wavelength of 220 nm. [Figure 6] FIG. 1 shows the molecular weight distribution of heat-treated product I measured by gel filtration HPLC at a wavelength of 220 nm. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Heat-treated soybean raw material) The heat-treated soybean raw material of the present invention can be added to beverages such as beer to impart excellent foaming properties and foam stability, as well as finer bubbles. The heat-treated product is characterized by the following A) to C). A) The crude protein content, calculated on a dry matter basis, is 14 to 35% by weight, the carbohydrate content is 55 to 85% by weight, and the lipid content is 1% by weight or less. B) In the molecular weight distribution at a wavelength of 220 nm measured by gel filtration HPLC, the ratio of the peak area of ​​the peptide region fraction having a weight-average molecular weight of 3,000 to 15,000 to the total peak area is 40% or more; C) When measuring the rate of change in foam size using a dynamic foam analyzer, the rate of change in foam size calculated using the following formula is 10% or less. Rate of change in bubble size (%) = {bubble size after 5 minutes of bubble generation (μm 2 ) - bubble size immediately after bubble generation (μm 2 )}÷bubble size immediately after generation (μm 2 ) x 100

[0010] (Soybean raw material) The soybean raw material of the present invention can be defatted soybeans or okara obtained in the process of producing isolated soybean protein. These can be used alone or in combination of two or more types. In the present invention, it is necessary to use soybean raw materials with a high crude protein content. By using such soybean raw materials, a heat-treated soybean raw material with high foaming power and foam stability can be obtained. For this reason, the crude protein content of soybean-derived raw materials must be 28 to 55% by weight, the sugar content 35 to 62% by weight, and the lipid content 5% by weight or less, calculated on a dry matter basis. In order to obtain the above-mentioned soybean raw material, it is desirable to use defatted soybeans alone as a raw material, or to mix defatted soybeans with okara obtained in the production process of isolated soy protein. The mixing ratio of defatted soybeans and okara can be appropriately mixed so that it falls within the above-mentioned range.

[0011] (Method for producing heat-treated soybean raw material) Water is added to the above soybean raw material, and the pH is adjusted using an acid such as hydrochloric acid to a value higher than 4 but not higher than 6, preferably higher than 4 but not higher than 5. The mixture is then heated at a temperature higher than 100°C but not higher than 160°C, preferably higher than 100°C but not higher than 130°C, more preferably at a temperature higher than 120°C but not higher than 130°C, for approximately 30 to 240 minutes, preferably 60 to 210 minutes, to obtain a slurry. After the heat treatment, the slurry is subjected to solid-liquid separation to obtain a filtrate (note that in the present invention, the liquid after solid-liquid separation may be referred to as a supernatant). The filtrate may or may not be purified so that the crude protein amount, carbohydrate amount, and lipid amount after purification are 14 to 35 wt %, 55 to 85 wt %, and 1 wt % or less, calculated on a dry matter basis. Thereafter, the filtrate is sterilized as necessary, and then dried by freeze drying, spray drying, or the like, to obtain the heat-treated product of the present invention.

[0012] (Crude protein amount) In the present invention, the crude protein content in the heat-treated product is determined by multiplying the total nitrogen content in the sample by the Kjeldahl method by a coefficient of 6.25, and measuring it as a percentage of the sample, expressed in dry matter terms. The crude protein content of the heat-treated product of the present invention is 14 to 35% by weight in dry matter equivalent. The lower limit can be selected preferably from 16% by weight or more, and 17% by weight or more. The upper limit can be selected preferably from 33% by weight or less, and 30% by weight or less. Preferred embodiments include, for example, 14 to 33 wt %, 14 to 30 wt %, 16 to 35 wt %, 16 to 33 wt %, 16 to 30 wt %, 17 to 35 wt %, 17 to 33 wt %, and 17 to 30 wt %.

[0013] (Measurement of molecular weight distribution by gel filtration chromatography) The conditions for gel filtration chromatography are not particularly limited, but the molecular weight distribution can be measured, for example, by the following method. HPLC is preferably used for gel filtration chromatography. Typical measurement conditions are shown below, but conditions that allow the molecular weight distribution to be measured with similar accuracy and precision to the conditions shown below can also be used. Measurement conditions Column: Tosoh Corporation HPLC columns TSK gel G3000PWXL (φ7.2 mm × 30 cm) and TSK gel G2000PWXL (φ7.2 mm × 30 cm) were used in conjunction. Eluent: 1% SDS, 1.17% NaCl, 50 mM phosphate buffer (pH 7.0) Test sample: Dissolve in the eluent to a concentration of 1% by weight, filter through a 0.45 μm filter, and then apply to the column. Column temperature: Flow rate: 0.4ml / min Detection: Wavelength 220nm Molecular weight markers: Thyroglobulin, γ-globulin, Albumin, Peroxidase, Myoglobin, Cytchrome C, Insulin, Reduced Glutathione, and p-aminobenzoic acid.

[0014] In the present invention, the proportion of the peptide region fraction having a weight-average molecular weight of 3,000 to 15,000 is important. That is, in the molecular weight distribution measured by gel filtration HPLC at a wavelength of 220 nm, the proportion of the peak area of ​​the peptide region fraction having a weight-average molecular weight of 3,000 to 15,000 to the total peak area must be 40% or more. This is preferably 44% or more, more preferably 45% or more, and even more preferably 50% or more.

[0015] (Sugar content) In the present invention, the amount of carbohydrates is measured by the phenol-sulfuric acid method. The amount of carbohydrates in the heat-treated product of the present invention is 55 to 85% by weight in terms of solid content. The lower limit can be selected preferably from 58% by weight or more, and 60% by weight or more. The upper limit can be selected preferably from 83% by weight or less, and 80% by weight or less. Preferred embodiments include, for example, 55 to 83% by weight, 55 to 80% by weight, 58 to 85% by weight, 58 to 83% by weight, 58 to 80% by weight, 60 to 85% by weight, 60 to 83% by weight, and 60 to 80% by weight.

[0016] (fat amount) The lipid content was calculated using the Soxhlet extraction method with diethyl ether. The lipid content of the heat-treated product of the present invention is 1% by weight or less, preferably 0.5% by weight or less, and more preferably 0% by weight, calculated on a dry basis.

[0017] (Fineness of bubbles) It is preferable that the bubbles generated in beverages and foods are small in size and that the resulting fine bubbles are stable. As an index of the fineness of the bubbles, the bubble size and the degree of stability of the bubbles were investigated. The bubble size was measured using a dynamic foam analyzer. A 0.3 wt% aqueous solution was prepared, and after sufficient degassing using an aspirator, the bubble size (μm) was measured using a dynamic foam analyzer (DFA100, manufactured by KRUSS) under the conditions in Table 1 below. 2 The rate of change of ) was measured. The rate of change in foam size is calculated using the following formula. The foam generation time is 10 seconds as shown in Table 1 below, and "immediately after foam generation" refers to the point 10 seconds after foam generation. If the rate of change in foam size is 10% or less, it is determined that fine foam can be sustained. (formula) Rate of change in bubble size (%) = {bubble size after 5 minutes of bubble generation (μm 2 ) - bubble size immediately after bubble generation (μm 2 )}÷bubble size immediately after generation (μm 2 ) x 100

[0018] (Table 1) TIFF0007771947000001.tif121152

[0019] (Foaming agent) The foaming agent of the present invention is a foaming agent containing, as an active ingredient, a heat-treated soybean raw material having the following A) to C): A) The crude protein content, calculated on a dry matter basis, is 14 to 35% by weight, the carbohydrate content is 55 to 85% by weight, and the lipid content is 1% by weight or less. B) In the molecular weight distribution at a wavelength of 220 nm measured by gel filtration HPLC, the ratio of the peak area of ​​the peptide region fraction with a weight-average molecular weight of 3,000 to 15,000 to the total peak area is 40% or more. C) When a 0.3 wt% aqueous solution is used and the rate of change in bubble size is measured using a dynamic foam analyzer, the rate of change in bubble size calculated using the following formula is 10% or less. Rate of change in bubble size (%) = {bubble size after 5 minutes of bubble generation (μm 2 ) - bubble size immediately after bubble generation (μm 2 )}÷bubble size immediately after generation (μm 2 ) x 100 is. The foaming agent of the present invention can impart good foaming properties, foam stability, and fine foam to foods and beverages. The foaming agent may consist solely of the heat-treated soybean raw material, or may further contain an emulsifier such as monoglyceride, or various other substances having foaming or foam-stabilizing effects. The content of the heat-treated soybean raw material in the foaming agent may be 10 to 100% by weight, preferably 50 to 100% by weight, and more preferably 90 to 100% by weight.

[0020] (food and drink) Foods and beverages that can be used in the present invention include meringue, confectioneries using meringue, frozen desserts and other ices, sparkling wine, beer, and beer-flavored beverages such as happoshu, third beer (which is made from ingredients other than malt or is mixed with another alcoholic beverage so as not to be classified as beer or happoshu under the Liquor Tax Act of Japan), fourth beer (which has a malt content of nearly 50% but also contains a distilled alcoholic beverage (liqueur) made from barley so as not to be classified as beer or happoshu under the Liquor Tax Act of Japan), and fermented or non-fermented non-alcoholic beer. The heat-treated product of the present invention is preferably used in beverages among foods and beverages, and among beverages, beer-flavored beverages such as happoshu (low-malt beer), third beer, fourth beer, and fermented or non-fermented non-alcoholic beer are preferred, as they can further enhance the effects on foam, such as fineness of the foam. Fermented or non-fermented non-alcoholic beer is more preferred, and non-fermented non-alcoholic beer is even more preferred. The amount of the heat-treated product or foaming agent of the present invention added to foods and drinks is, for example, preferably 0.001 to 1 wt %, more preferably 0.005 to 0.5 wt %, based on the weight of the beverage as the heat-treated product. For frozen desserts, the amount is preferably 0.005 to 10 wt %, more preferably 0.01 to 5 wt %, based on the weight of the frozen dessert as the heat-treated product. For meringues, the amount is preferably 0.05 to 5 wt %, more preferably 0.1 to 3 wt %, based on the weight of the egg white used as the heat-treated product.

[0021] (Beer-flavored beverage) The beer-flavored beverage of the present invention is a happoshu, a third beer (a beer made from ingredients other than malt or made by mixing happoshu with another alcoholic beverage so as not to be classified as beer or happoshu under the Liquor Tax Act of Japan), a fourth beer (a beer made by increasing the malt content to nearly 50% but adding a distilled alcoholic beverage (liqueur) made from barley so as not to be classified as beer or happoshu under the Liquor Tax Act of Japan), or a fermented or non-fermented non-alcoholic beer. The amount of the heat-treated product or foaming agent of the present invention added to a beer-taste beverage is preferably 0.001 to 1 wt %, more preferably 0.005 to 0.5 wt %, of the heat-treated product relative to the weight of the beverage.

[0022] The beer-taste beverage of the present invention may contain other ingredients, such as sugars, sugar alcohols, various glycosides such as saponin, flavorings, dietary fiber and polysaccharides, peptides such as soybean peptides, acids, and yeast extract. Examples of sugars include reducing sugars such as glucose, fructose, and maltose, oligosaccharides such as sucrose, and various dextrins and oligosaccharides. Examples of flavorings include malt flavor, hop flavor, beer flavor, alcohol flavor, and caramel flavor. Malt flavor is preferred as a flavoring that imparts and reinforces the beer flavor. Examples of acids include organic acids such as citric acid, lactic acid, and tartaric acid, and mineral acids such as hydrochloric acid and phosphoric acid. Hops or hop extracts, and bittering agents can also be used in combination. Hops or hop extracts refer to hop leaves or their crushed products, extracts obtained by extracting these with water or hot water, and concentrates or dried extracts. The bittering agent can be a conventionally known bittering agent selected from hop-derived bitter substances, caffeine, gentian extract, peptides, theobromine, naringin, bitter oak extract, artemisia extract, cinchona extract, etc.

[0023] (Beer-flavored beverage manufacturing method) The production of the beer-taste beverage of the present invention will be explained using a non-fermented, non-alcoholic beer as an example. In the present invention, the process employed is that typically employed in the production of non-fermented, non-alcoholic beer. For example, a primary raw material liquid containing the food material, malt, etc., of the present invention as raw materials is boiled, followed by the addition of a hop extract and flavoring, followed by reheating, and optionally adding fermented alcohol, followed by the addition of carbonation. If necessary, precipitates can be separated and removed at each stage by filtration, centrifugation, or the like. Alternatively, carbonated water can be added after the raw material liquid is prepared in a concentrated state. These processes, which utilize typical soft drink production processes, allow for the convenient preparation of a beer-flavored beverage with a good flavor, even without fermentation equipment. Removing precipitates before the carbonation or carbonated water addition process is more desirable, as it removes sediment and substances that cause unpleasant flavors. Furthermore, sterilization can be performed, if necessary, before the carbonation or carbonated water addition process.

[0024] The pH of the beer-taste beverage of the present invention is not particularly limited, but is generally between pH 3 and 5. Preferably, it is between pH 3 and 4.5, and more preferably between pH 3 and 4. If the pH is too low, the acidity may be too strong, affecting the flavor. If the pH is too high, the bactericidal effect may be reduced, and the shelf life may be reduced.

[0025] Examples are described below. In the examples, % is by weight. In the following, the heat-treated soybean raw material is simply referred to as the heat-treated product.

[0026] Example 1 Dried defatted soybeans obtained during the soybean oil extraction process, with a moisture content of 6%, a dry matter equivalent of 48% crude protein, 42% sugars, and 2% lipids, were added to 15 volumes of water, adjusted to pH 4.4 with hydrochloric acid, and subjected to heat extraction at 126°C for 2.5 hours. The pH of the heat-extracted slurry after cooling was 4.7. The pH of the recovered slurry was adjusted to 5.0 with sodium hydroxide and then centrifuged (10,000 x G, 30 minutes) to separate the supernatant and precipitate. This supernatant was desalted by electrodialysis and then freeze-dried to obtain heat-treated product A.

[0027] Example 2 Dried defatted soybeans obtained in the soybean oil extraction process and dried okara obtained in the soy protein isolate production process were mixed to obtain a dry soybean raw material with a moisture content of 5%, a crude protein content of 40%, a sugar content of 52%, and a lipid content of 1%. The resulting mixture was then mixed with 15 volumes of water, adjusted to a pH of 4.4 with hydrochloric acid, and subjected to heat extraction at 126°C for 2.5 hours. The pH of the heat-extracted slurry after cooling was 4.8. The pH of the recovered slurry was adjusted to 5.0 with sodium hydroxide and then centrifuged (10,000 x G, 30 minutes) to separate the supernatant and precipitate. The supernatant was desalted by electrodialysis and then freeze-dried to obtain heat-treated product B.

[0028] Example 3 Dried defatted soybeans obtained in the soybean oil extraction process and dried okara obtained in the soy protein isolate production process were mixed to produce a dried soybean raw material with a moisture content of 6%, a crude protein content of 33%, a sugar content of 60%, and a lipid content of 1% on a dry matter basis. 15 volumes of water were added to the resulting mixture, the pH was adjusted to 4.4 with hydrochloric acid, and the mixture was heated and extracted at 126°C for 2.5 hours. The pH of the heated and extracted slurry after cooling was 4.8. The pH of the recovered slurry was adjusted to 5.0 with sodium hydroxide and then centrifuged (10,000 x G, 30 minutes) to separate the supernatant and precipitate. This supernatant was desalted by electrodialysis and then freeze-dried to obtain heat-treated product C.

[0029] Example 4 Dried defatted soybeans obtained in the soybean oil extraction process and dried okara obtained in the soy protein isolate production process were mixed to obtain a dried soybean raw material with a moisture content of 6%, a crude protein content of 30%, a sugar content of 62%, and a lipid content of 1% on a dry matter basis. 15 volumes of water were added to the resulting mixture, the pH was adjusted to 4.4 with hydrochloric acid, and the mixture was heated and extracted at 126°C for 2.5 hours. The pH of the heated and extracted slurry after cooling was 4.8. The pH of the recovered slurry was adjusted to 5.0 with sodium hydroxide and then centrifuged (10,000 x G, 30 minutes) to separate the supernatant and precipitate. The supernatant was desalted by electrodialysis and then freeze-dried to obtain Heat-Treated Product D.

[0030] (Comparative Example 1) Dried okara (soybean curd refuse) obtained in the soy protein isolate production process, which had a moisture content of 5% and a dry matter equivalent of 24% crude protein, 71% sugar, and 1% lipid, was added to a 15-fold volume of water, adjusted to pH 4.4 with hydrochloric acid, and subjected to heat extraction at 126°C for 2.5 hours. The pH of the heat-extracted slurry after cooling was 4.5. The pH of the recovered slurry was adjusted to 5.0 with sodium hydroxide and then centrifuged (10,000 x G, 30 minutes) to separate the supernatant and precipitate. This supernatant was desalted by electrodialysis and then freeze-dried to obtain heat-treated product E.

[0031] (Comparative Example 2) Soy protein isolate with a moisture content of 6%, a dry matter equivalent of 90% crude protein, 1.3% carbohydrates, and 2% lipids was added to 15 volumes of water, adjusted to pH 4.4 with hydrochloric acid, and subjected to heat extraction at 126°C for 2.5 hours. The pH of the heat-extracted slurry after cooling was 4.5. The pH of the recovered slurry was adjusted to 5.0 with sodium hydroxide and then centrifuged (10,000 x G, 30 minutes) to separate the supernatant and precipitate. This supernatant was desalted by electrodialysis and then freeze-dried to obtain heat-treated product F.

[0032] (Comparative Example 3) Dried defatted soybeans obtained in the soybean oil extraction process, with a moisture content of 6%, a dry matter equivalent of 48% crude protein, 42% sugar, and 2% lipid, were added to 15 volumes of water, adjusted to pH 6.5 with hydrochloric acid, and subjected to heat extraction at 126°C for 1 hour. The pH of the heat-extracted slurry after cooling was 6.5. The pH of the recovered slurry was adjusted to 5.0 with sodium hydroxide and then centrifuged (10,000 x G, 30 minutes) to separate the supernatant and precipitate. This supernatant was desalted by electrodialysis and then freeze-dried to obtain heat-treated product G.

[0033] Comparative Example 4 Dried soybean raw material obtained in the soy protein isolate production process, which had a moisture content of 6%, a dry matter equivalent of 48% crude protein, 42% carbohydrates, and 2% lipids, was added with 15 volumes of water, adjusted to pH 2.5 with hydrochloric acid, and subjected to heat extraction at 126°C for 1 hour. The pH of the heat-extracted slurry after cooling was 3.0. The pH of the recovered slurry was adjusted to 5.0 with sodium hydroxide and then centrifuged (10,000 x G, 30 minutes) to separate the supernatant and precipitate. This supernatant was desalted by electrodialysis and then freeze-dried to obtain heat-treated product H.

[0034] (Comparative Example 5) Dried soybean raw material obtained in the tofu manufacturing process, which contained 40% crude protein, 25% carbohydrate, and 19% lipid (on a dry matter basis), was added with 15 times the volume of water, adjusted to pH 4.4 with hydrochloric acid, and subjected to heat extraction at 126°C for 2.5 hours. The pH of the heat-extracted slurry after cooling was 4.7. The pH of the recovered slurry was adjusted to 5.0 with sodium hydroxide and then centrifuged (10,000 x G, 30 minutes) to separate the supernatant and precipitate. This supernatant was desalted by electrodialysis and then freeze-dried to obtain Heat-Treated Product I.

[0035] The sugar content, crude protein content, crude ash content, and lipid content of the heat-treated products obtained in Examples 1 to 4 and Comparative Examples 1 to 5 are shown in Table 2. The sugar content was measured by the phenol-sulfuric acid method, the crude ash content was measured by the ashing method, and the lipid content was measured by the Soxhlet extraction method using diethyl ether. The proportion of the peptide region fraction with a weight-average molecular weight of 3,000 to 15,000 was determined by molecular weight distribution measurement using gel filtration chromatography. The molecular weight distributions of the heat-treated products A to I were measured by gel filtration HPLC at a wavelength of 220 nm, and the results are shown in charts in FIGS.

[0036] (Table 2) Analytical values ​​of heat-treated products TIFF0007771947000002.tif78166

[0037] The heat-treated products obtained in Examples 1 to 4 and Comparative Examples 1 to 5 were measured using a dynamic foam analyzer, and the results are shown in Table 3.

[0038] (Table 3) TIFF0007771947000003.tif55166

[0039] The heat-treated products A to D have a rate of change in bubble size of 10% or less, and the fine bubbles that are generated are stable. On the other hand, the bubble size change rates were poor for heat-treated product E, which had a low crude protein content; heat-treated product F, which had a high crude protein content and a low carbohydrate content; heat-treated product G, which had a low carbohydrate content; heat-treated product H, which had a low proportion of the peptide fraction with a weight-average molecular weight of 3,000 to 15,000, a low carbohydrate content, and a high crude protein content; and heat-treated product I, which had a high oil content.

[0040] In order to confirm whether the heat-treated products A to D that meet the requirements of the present invention impart good foaming properties, bubble stability, and fine bubble texture to foods and beverages, we next confirmed whether the present invention has any effect on various foods and beverages.

[0041] (Foaming / Foam Stability in Non-Alcoholic Beer) (Examples 5 to 8, Comparative Examples 6 to 11) To 30 ml of commercially available non-fermented non-alcoholic beer, 150 mg of a 20% aqueous solution of heat-treated products A to I was added (the concentration of heat-treated products A to I in the beverage was 0.1%) and gently stirred. This mixture was poured into a 100 ml colorimetric tube without creating foam, and pulsed twice using an ultrasonic generator ("Sonic Hour," manufactured by Takara Tomy Arts Co., Ltd.). The foam volume (ml) was measured and foaming power was evaluated. After pulse irradiation, the mixture was left to stand for 2 minutes, and foam stability was evaluated using the formula below. A control without any additives was also prepared under the same conditions. A foam volume of less than 40 ml immediately after irradiation was rated as x, a foam volume of 40 ml or more was rated as ◯, and a foam volume of 50 ml or more was rated as ⊚. Furthermore, when the residual bubble rate was less than 80%, the bubble stability was evaluated as ×, when it was 80% or more, the bubble stability was evaluated as ◯, and when it was 90% or more, the bubble stability was evaluated as ⊚. Foam remaining rate (%) = foam volume (ml) 2 minutes after irradiation ÷ foam volume (ml) immediately after irradiation × 100

[0042] The results of foaming ability, foam residual rate, and foam stability are shown in Table 4.

[0043] (Table 4) TIFF0007771947000004.tif85165

[0044] The non-alcoholic beers to which the heat-treated products A to D were added (Examples 5 to 8) had higher foaming properties and foam stability than the non-alcoholic beer without the heat-treated products (Comparative Example 11). Among these, the beers to which the heat-treated products B and C were added (Examples 6 and 7) had better foaming properties and foam stability. Furthermore, non-alcoholic beer to which heat-treated product E, which had a high proportion of the peptide region fraction with a weight-average molecular weight of 3,000 to 15,000 and a high sugar content but a low crude protein content, was added exhibited excellent foam stability but poor foaming properties. Heat-treated product F, which had a very high crude protein content and a very low sugar content, exhibited poor foaming properties. Heat-treated product G, which had a low sugar content, exhibited poor foaming properties. Non-alcoholic beer to which heat-treated product H, which had a low proportion of the peptide region fraction with a weight-average molecular weight of 3,000 to 15,000 and a high crude protein content, was added exhibited poor foaming properties and foam stability. Heat-treated product I, which had a high oil content, exhibited poor foaming properties and foam stability.

[0045] (Evaluation of Foaming and Foam Quality in Non-Alcoholic Beer) (Example 9, Comparative Examples 12 to 14) 500 mg of a 20% aqueous solution of heat-treated product A was added to 100 ml of commercially available non-alcoholic beer (the concentration of heat-treated product A in the beverage was 0.1%) and gently stirred. The mixture was poured into a glass, allowed to stand for 2 minutes, and compared using the method described below (Example 9). As a control, a sample containing no added alcohol was compared under the same conditions (Comparative Example 12). In addition, a commercially available beer ("Premium Malt's", manufactured by Suntory) containing no heat-treated product was evaluated in the same manner as in Example 9 (Comparative Example 13). Furthermore, instead of the heat-treated product of the present invention, soybean peptide ("Hinute-DC6", manufactured by Fuji Oil Co., Ltd.) and soybean polysaccharide ("SOYAFIVE-S-LA200", manufactured by Fuji Oil Co., Ltd.) were mixed so that the sugar content and crude protein content were the same as those of heat-treated product A, and this was evaluated in the same manner as in Example 9 (Comparative Example 14). When the molecular weight distribution of Comparative Example 14 was measured, the proportion of the peptide region fraction with a weight-average molecular weight of 3,000 to 15,000 was 35.6%.

[0046] (Sensory evaluation method) The quality of foam during drinking was evaluated by a sensory evaluation conducted by 10 well-trained panelists according to the following criteria. The 10 panelists rated each item on a scale of 1 to 5, and the number of people who gave an evaluation for each score is shown in Table 5. The average score was calculated from the number of people who gave each score. A beer with an average score of 4.0 or higher for each item was deemed to pass.

[0047] (Fineness of bubbles) 5 points: The bubbles are clearly finer than the control. 4 points: The bubbles are slightly finer than the control. 3 points: No difference compared to the control 2 points: The control has slightly finer bubbles 1 point: The control has finer bubbles

[0048] (Amount of bubbles generated when poured into a container) 5 points: Clearly more bubbles than the control 4 points: Slightly more bubbles than the control 3 points: No difference compared to the control 2 points: The control had slightly more bubbles 1 point: The control has more bubbles

[0049] (Beer-like foam when drinking) 5 points: Compared to the control, it has a clearly beer-like foam feel. 4 points: Slightly more beer-like foam than the control 3 points: No difference compared to the control 2 points: The control has a beer-like foam feel. 1 point: The control clearly has a beer-like foam feel.

[0050] (Table 5) TIFF0007771947000005.tif85163

[0051] The non-alcoholic beer to which heat-treated product A was added (Example 9) received a high evaluation score of 4.0 points or more on average, and had better foaming properties, finer bubbles, and a beer-like foam texture than the non-additive beer. Furthermore, when the non-alcoholic beer to which heat-treated product A was added was compared with a commercially available fermented beer (Comparative Example 13) that had good foaming properties and fine bubbles, it was confirmed that the foaming properties, fine bubbles, and foamy feel when drinking of the non-alcoholic beer to which heat-treated product A was added were at the same level as the commercially available fermented beer (Example 9, Comparative Example 13). On the other hand, when a mixture of soybean peptides and water-soluble soybean polysaccharides was added as in Comparative Example 14, the foaming properties, fineness of the bubbles, and beer-like foam texture were better than when no addition was made, but the results were inferior in all respects to when heat-treated product A was added.

[0052] From the above results, it was confirmed that heat-treated soybean raw materials that: A) have a crude protein content of 14-35% by weight, a carbohydrate content of 55-85% by weight, and a lipid content of 1% by weight or less, calculated on a dry matter basis; B) in the molecular weight distribution at a wavelength of 220 nm measured by gel filtration HPLC, the ratio of the peak area of ​​the peptide region fraction with a weight-average molecular weight of 3000-15000 to the total peak area is 40% or more; and C) when a 0.3 wt% aqueous solution is used and the rate of change in bubble size is measured using a dynamic foam analyzer, the rate of change in bubble size is 10% or less, impart good foaming properties, bubble stability, and fine bubble texture to foods and beverages.

Claims

1. A heat-treated soybean raw material having the following A) to C). A) Crude protein content is 16-30% by weight, carbohydrate content is 60-80% by weight, and lipid content is 1% by weight or less, calculated on a dry matter basis. B) In the molecular weight distribution at a wavelength of 220 nm measured by gel filtration HPLC, the ratio of the peak area of ​​the peptide region fraction with a weight-average molecular weight of 3,000 to 15,000 to the total peak area is 45% or more. C) When a 0.3 wt% aqueous solution is used and the rate of change in bubble size is measured using a dynamic foam analyzer, the rate of change in bubble size calculated using the following formula is 10% or less. Rate of change in bubble size (%) = {bubble size after 5 minutes of bubble generation (μm 2 ) - bubble size immediately after bubble generation (μm 2 )}÷bubble size immediately after bubble generation (μm 2 ) x 100

2. A foaming agent containing the heat-treated soybean raw material according to claim 1 as an active ingredient.

3. A method for producing a heat-treated soybean raw material having the following A) to C), characterized in that a soybean-derived raw material having a crude protein content of 33 to 48% by weight, a carbohydrate content of 35 to 62% by weight, and a lipid content of 5% or less, on a dry matter basis, is heated under conditions of above 100°C and below 160°C, and above pH 4 and below pH 6, to obtain a slurry, and the filtrate obtained after solid-liquid separation of the slurry has a crude protein content of 16 to 30% by weight, a carbohydrate content of 60 to 80% by weight, and a lipid content of 1% or less, on a dry matter basis. A) Crude protein content is 16-30% by weight, carbohydrate content is 60-80% by weight, and lipid content is 1% by weight or less, calculated on a dry matter basis. B) In the molecular weight distribution at a wavelength of 220 nm measured by gel filtration HPLC, the ratio of the peak area of ​​the peptide region fraction having a weight-average molecular weight of 3,000 to 15,000 to the total peak area is 45% or more; C) When a 0.3 wt% aqueous solution is used and the rate of change in bubble size is measured using a dynamic foam analyzer, the rate of change in bubble size calculated using the following formula is 10% or less. Rate of change in bubble size (%) = {bubble size after 5 minutes of bubble generation (μm 2 ) - bubble size immediately after bubble generation (μm 2 )}÷bubble size immediately after bubble generation (μm 2 ) x 100

4. A method for producing a beverage, comprising the step of adding the heat-treated product described in claim 1 or 2 in an amount of 0.005 to 0.5% by weight relative to the weight of the beverage.

5. A method for imparting foaming properties, bubble stability or fine bubble texture to a beverage, comprising the step of adding 0.005 to 0.5 weight % of the heat-treated product described in claim 1 or 2 to the weight of the beverage.

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