JPH0365138B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention provides a method for fractionating and producing soybean protein components. (Prior art) Traditionally, soybean protein raw materials are extracted and separated in an aqueous system (water-soluble fraction and insoluble fraction = commonly known as Okara), and the water-soluble fraction is subjected to isoelectric precipitation (PH4-5, usually pH4.2-
4.6) The so-called soybean protein production is carried out by neutralizing the resulting precipitate fraction and drying it to separate the soybean protein. By the way, soybean protein is composed of various proteins with complex higher-order polymer structures. For example, in the method of fractionating soybean protein by ultracentrifugation based on the difference in sedimentation constant, soybean protein is composed of various proteins with complex higher-order structures. These proteins have different physical properties as well. Furthermore, each protein is composed of several subunits, for example, the 7S protein is composed of 3 subunits, and the 11S protein is composed of 12 subunits. These proteins and subunits can be obtained with various changes (higher-order structure changes, interactions between subunits, etc.) due to changes in the environment (ionic strength, PH, temperature, concentration, etc.), and their properties can also vary. There are many research reports on this. Taking advantage of these facts, many soybean protein fractionation methods have been attempted. Slight differences among these many fractionation methods (differences in ionic strength, pH, presence of certain salts, concentration, temperature, operating procedures, etc.) may affect the physical properties and functions of the fractionated and isolated soybean protein. The chemical properties etc. have changed considerably. This is caused not only by the composition ratio of proteins such as 7S and 11S mentioned above, but also by changes in higher order structure, interactions between proteins and between subunits, etc. Conventionally known separation (fractionation) of soybean protein
An example of the law is as follows. That is, for example, Nario et al. fractionated the 11S component and the 7S component using a rare calcium salt (Japanese Patent Application No. 1989-90289). Super mountain etc.
7S protein can be produced by removing the insoluble fraction in the presence of sodium chloride or potassium chloride at pH 1.2 to 4.0 (Japanese Patent Application No. 1972-72606), or after extraction at pH 5.40 to 5.85.
7S protein is produced by isoelectric precipitation at pH 4.5 (patent application 1983-31168). Shimmer etc. has a pH of approximately 5.1 to 5.9.
A heat-coagulable viscous protein is produced by extracting it with water (Japanese Patent Application No. 150762, 1972). Mashima et al. used 1st stage fractionation at PH6.0 to 7.0, 2nd stage fractionation at PH5.0 to 5.6, and PH4.0 to 4.8.
Proteins are produced by separating the second and third fraction proteins individually through the third stage fractionation.
60899). Osil etc. are extracted with an aqueous extractant and the pH is approx.
Generate an extract of 6.5 and adjust to isoelectric point, approximately 115~
It is heated to 145 degrees F and concentrated to more than 44% (patent application 1982-121275). Ortho-fur etc. is made from plant protein-containing slurry in the presence of sulfite ions at a pH of 6.5~
8.0 to extract and dry the water-soluble components to obtain an isolated product (patent application 1982-216003). Lanehart et al.
The isoelectrically precipitated slurry was adjusted to pH 5.0 to 5.6, and the salt concentration was adjusted to a molar concentration of 0.01 to 0.2M, followed by 7S.
The 11S fraction is separated (Japanese Patent Application No. 139105, 1982). In the laboratory, soybean protein fractionation methods have been studied and reported by Erdouritzi et al., Blitzu et al., Wolff et al., and Tan et al. For example, tongue is made from defatted soybeans using Tris-HCl buffer (PH7.8, containing β-mercaptoethanol).
After extraction, the insoluble fraction was removed by centrifugation at 10,000 rpm.The extract was adjusted to pH 6.6, and after dialysis, the insoluble fraction was centrifuged at 10,000 rpm.
The 7S globulin is fractionated by centrifugation into the 11S fraction and crude 7S fraction, and the crude 7S fraction is isoelectrically precipitated, washed with water, and lyophilized. Yamauchi et al.
We study 11S globulin by washing the 11S fraction with water, neutralizing it, and dissolving it in a buffer solution. However, these methods still remain in the realm of laboratory methods and have a number of problems as described below in order to be commercialized. (Problems to be Solved by the Invention) The inventors of the present invention simply used Tris-HCl buffer as a means of conducting further tests and improving the conventional technology for the purpose of fractionating and producing industrially practical soybean protein. If you just adjust the pH instead of using acids etc., the crude 11S fraction and the crude
Reagents such as Tris-HCl buffer and β-mercaptoethanol, which cannot extract and separate the 7S fraction, cannot be used in the food industry, especially for β-mercaptoethanol.
-Mercaptoethanol has a strong unpleasant odor and cannot be used in food because of its flavor. The extract obtained by removing the insoluble fraction by centrifugation and adjusting the pH to 6.6 is extremely viscous and contains the crude 11S fraction and the crude When separating the 7S fraction using an industrial continuous centrifugation method using a low centrifugal force (for example, using a decanter), we encountered problems such as difficulty in separating the precipitated slurry and the solution portion. Therefore, as a result of intensive research, we have found that soy protein raw materials can be treated with sulfite compounds, glutathione compounds, or cysteine compounds in an aqueous system with a pH of 6.5 or higher, and that soy protein raw materials can be treated with pH 5.5 to 7.0 and
It is important to fractionate into soluble and insoluble fractions by moving to a temperature below 20°C.
It is possible to fractionate and produce soybean proteins with different properties that are excellent in flavor, and it is also possible to use industrial continuous centrifugation, which has traditionally been difficult to use, especially when soybean proteins contain soybean polysaccharides. The present inventors have discovered that practical separation is extremely easy using a separator (such as a decanter), and have completed the present invention. (Means for Solving the Problems) The present invention involves treating soybean protein raw materials in the presence of a sulfite compound, a glutathione compound, or a cysteine compound in an aqueous system with a pH of 6.5 or higher, and at a pH of 5.5 to 7.0 and at 20°C. The soluble fraction (less than
This is a method for producing soybean protein that consists of fractionating it into an insoluble fraction (hereinafter referred to as the P1 fraction) and an insoluble fraction (hereinafter referred to as the P1 fraction). As the soybean protein raw material used in the present invention, any raw material containing soybean protein can be used, such as soybean, defatted soybean, soybean milk (including dry powder), concentrated soybean protein, and isolated soybean protein. Preferably soybeans, defatted soybeans,
Soy protein raw materials that contain both soy protein and insoluble polysaccharides, such as concentrated soy protein, have a higher S1 fraction and P1 fraction.
This is suitable because separation of fractions becomes easier. The sulfite ion compound referred to in the present invention refers to a compound that generates sulfite ions in an aqueous system, such as potassium or sodium alkali metal sulfite (sulfite, bisulfite, pyrosulfite, metabisulfite, etc.)
Mention may be made of salts, other water-soluble salts and cationic (eg ammonium, mixtures thereof) salts, sulfur dioxide gas. Although it depends on the protein content of soybean protein raw materials, sulfite compounds are
An amount of 0.5% by weight or more, preferably 1.0% by weight or more is appropriate; less than 0.5% by weight is not preferred because the purity of the S1 fraction, in other words, the specificity of the protein in the S1 fraction decreases. The glutathione compound or cysteine compound referred to in the present invention is glutathione, cysteine, or a salt thereof, such as a hydrochloride, and is usually 5 mmole or more, preferably 10 mmole or more, based on the soybean protein raw material.
m mole or more is used, but each fraction obtained is good in terms of flavor and hygiene, as it does not exhibit a strong odor like mercaptoethanol. In the presence of the above compound, once the PH is 6.5 or higher,
Preferably PH is 7.1-9, more preferably 7.5-8.5
The soybean protein raw material is processed in aqueous system. If the pH is less than 6.5, not only will the above compound not be effective, but the yield of the S1 fraction will decrease, which is undesirable. Moreover, when the pH exceeds 9, a characteristic odor due to alkali may occur.
For the aqueous treatment, a known mixing/stirring device that dissolves and extracts protein from soybean protein raw materials can be used. The larger the amount of aqueous solvent, the easier it is to dissolve and extract proteins, but if it is too large,
Separation of P1 fraction becomes poor and protein in P1 fraction becomes S1.
Since it tends to be mixed into the fraction, it is appropriate to use 30 times or less of the soybean protein raw material. The soy protein raw material containing the aqueous solvent is then
5.5 to 7.0 (preferably PH6.0 to 6.9) and below 20℃.
fraction). In other words, below PH5.5
The yield of S1 fraction is low, and conversely, if the pH exceeds 7.0, S1
This is industrially unfavorable because the purity of the fraction decreases and its viscosity increases. If the temperature is higher than 20℃,
Separation between S1 and P1 fractions becomes poor and the purity of S1 fraction decreases. However, the temperature is such that the soybean protein raw material containing the aqueous solvent does not freeze, and the separation property decreases in a frozen state. As the means of separation, known separation means (filtration, centrifugation, etc.) can be used, and in particular, even if a continuous centrifuge (e.g. decanter) etc. is used, it is easy to separate the P1 fraction and the S1 fraction in a continuous manner. It can be separated into
Of course, this does not preclude the use of discontinuous type centrifuges such as batch type centrifuges. As mentioned above, the P1 fraction and
Continuous centrifuges such as decanters and nozzle separators have the effect of making separation of the S1 fraction extremely easy. The batch method or laboratory method is used to separate the water-soluble fraction and the insoluble fraction, which are obtained by separating and removing the insoluble fraction by centrifugation, etc., and adjusting the water-soluble fraction to pH 6.7 and 3°C. It requires a strong centrifugal force (approximately 10,000 rpm), and a continuous centrifugal separator such as a decanter (approximately 2,000 rpm) is required.
Even if centrifugation is attempted using a weak centrifugal force of ~2500 rpm, it is extremely difficult to separate the S1 and P1 fractions. The P1 fraction is further transferred to a warm water system and dispersed or dissolved, and the dispersed or dissolved fraction (S2 fraction)
can also be separated. The appropriate temperature of the water used to disperse and dissolve the S2 fraction from the P1 fraction is at least 11°C or higher, preferably 21°C or higher, and more preferably 30 to 60°C, and the pH at this time is 6 or higher. Preferably, 6.7 to 9 is appropriate, and the S2 fraction contained in the P1 fraction can be easily dispersed and dissolved. The above S1 fraction, P1 fraction, or S2 fraction can be used as is, or after being concentrated or dried, as a soybean protein that exhibits properties different from conventional isolated soybean proteins. As a means of concentration,
The method of isoelectrically precipitating each fraction and separating and recovering the precipitated fraction is preferably accompanied by washing with water, so that a product that is favorable in terms of taste and hygiene can be obtained, and after isoelectric precipitation, neutralization and heat sterilization are performed. Alternatively, further enzymatic treatment using protease or the like can be performed. It is most commonly in a sterilized and dried form (hereinafter, the dried products obtained from the S1 fraction or S2 fraction will be referred to as the D1 fraction and D2 fraction, respectively). The heat sterilization treatment can be performed using known temperatures, times, and equipment known as HTST and UHT treatments. As shown in the examples below, each fraction obtained has different properties such as gel strength, viscosity, and transparency.
Since it exhibits properties different from those of isolated soybean protein obtained by conventional methods, it becomes possible to utilize soybean protein in a more advanced manner. The present invention will be explained below with reference to Examples. Example 1 90 parts of defatted soybeans (the following parts indicate parts by weight), 900 parts of water, and 1.26 parts of sodium hydrogen sulfite (sodium bisulfite) were stirred and extracted for 30 minutes under the condition of PH 7.8, and then extracted as it was. -PH6.25 using N hydrochloric acid
The temperature was adjusted to 5°C or lower (ice-cooled) for 30 minutes. Using a continuous centrifuge (decanter) at 2500 R.PM, separate the precipitated fraction (P1 fraction) and the non-precipitated fraction (S1 fraction).
The S1 fraction was adjusted to pH 4.5, subjected to isoelectric precipitation, and the precipitated fraction was separated. To this was added 500 parts of water, stirred, washed with water, and similarly centrifuged to obtain a precipitate fraction.
After neutralization, this precipitated fraction was heated at 135° C. for 30 seconds and spray-dried to obtain 12.6 parts of a dried product (D1 fraction). On the other hand, the previously obtained P1 fraction was stirred and dispersed or dissolved in 500 parts of warm water at pH 8.0 and 50°C, and the precipitated fraction was removed using a decanter to obtain the dispersed or dissolved fraction (S2 fraction). The S2 fraction was adjusted to pH 4.5, subjected to isoelectric precipitation, and the precipitated fraction was separated using a decanter. After neutralization, this was heat-treated and spray-dried to obtain a dried product (D2 fraction). I got 12.8 copies. No unpleasant odor was detected during the process or in the S1, S2, D1, and D2 fractions obtained. Experimental Example 1 The physical properties of the D1 fraction, D2 fraction obtained in Example 1, and SPI obtained by the following method (normal method) were compared. (Preparation of SPI) Add 1 part of the same defatted soybean as used in Example 1 to 10 parts of water.
The soy milk obtained by centrifuging and removing the okara was subjected to isoelectric precipitation to obtain a curd, which was washed with 10 parts of water, neutralized, and then heated in the same manner as in Example 1.
SPI was obtained by spray drying. (NSI measurement method and results) Disperse 3.5 g of sample in 100 ml, 450 rpm at 40°C.
After extraction for 60 minutes with propeller stirring, the supernatant and precipitate were centrifuged at 2500 rpm and extracted again in the same manner.
Combine the supernatant obtained by centrifugation, measure the crude protein content using the Kjeldahl method, and divide this by the crude protein of the sample to determine the NSI. As a result, the D1 fraction showed a high NSI value of 92 and the D2 fraction 93, which was as high as the SPI. (Measurement method and results of gel forming property and viscosity) 12 g of sample (powder) and 88 g of water (or 2.5% saline)
ml, homogenized (1200 rpm for 3 minutes), centrifuged to defoam (2500 rpm for 10 minutes), heated at 80℃ for 30 minutes, and measured the gel strength ( g/cm ² ) or viscosity (cps) was measured. The results are shown in the table below.

[Table] The D1 fraction is brittle in the salted gel state but has high viscosity without salt, whereas the D2 fraction shows strong strength in the salted gel state and low viscosity in the unsalted state. It was. (Transparency measurement method and results) Turbidity at each concentration at PH7.0 (OD600n
m) was measured. The results are shown in Figure 1. As described above, the D1 and D2 fractions were different from SPI in terms of gelling power, consistency, transparency, etc. The D2 fraction was white in color and formed a hard gel, closely resembling a kamaboko. Example 2 In the same method as in Example 1, D2 was prepared by changing the ratio (weight ratio) of sodium bisulfite and defatted soybeans.
The recovery rate of the fractions was examined. The results are shown in Figure 2. However, the yield of the D2 fraction in Example 1 is taken as 100 and shown in relative terms. As is clear from this figure, it can be seen that sodium bisulfite is required to be at least 0.5% by weight/defatted soybean, preferably 1.0% by weight/defatted soybean. D1 in the absence of sodium bisulfite
This shows that it is difficult to separate the fraction and D2 fraction. Example 3 In the same manner as in Example 1, cysteine hydrochloride and glutathione were each used in amounts of 15 mmole per 100 g of defatted soybeans instead of sodium bisulfite, and treated in the same manner as in Example 1 to obtain fractions D1 and D2. Example 1
The following table shows the relative recovery rate when the recovery rate of the D2 fraction is set as 100.

[Table] Comparative Example 1 1 part defatted soybean and 10mM β-mercaptoethanol in PH7.8 Tris-HCl buffer (63mM)
Add 15 parts, stir and extract, centrifuge at 10,000 rpm, remove the insoluble fraction (Okara), and dilute the resulting liquid with 2N
The pH was adjusted to 6.6 with hydrochloric acid, cooled on ice, left at 2-3°C for 3 hours, and then decanted, but it was difficult to separate the precipitated fraction and the water-dispersed fraction. Therefore, the supernatant fraction (S1
fraction) and a precipitate fraction, and the precipitate fraction was dispersed in a phosphate buffer solution of PH7.6 (S2 fraction). S1 fraction,
The S2 fraction had an unpleasant odor of mercaptoethanol and contained a buffer solution, so it was hardly edible. (Effects) As detailed above, the present invention has made it possible to industrially fractionate soybean protein components.
More specifically, it is possible to separate the P1 fraction, including the S1 and S2 fractions, without using reagents such as Tris-HCl buffer or mercaptoethanol, which has a strong unpleasant odor and cannot be used in food products due to its flavor. Furthermore, it has become possible to easily separate the S1 fraction and P1 fraction using an industrial continuous centrifuge (for example, a decanter).
By separating the S2 fraction from the P1 fraction, industrial separation of the S1 and S2 fractions has become easier and will greatly contribute to the development of industry.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating the turbidity of an aqueous dispersion of D1 fraction, D2 fraction, and SPI obtained according to the present invention. FIG. 2 is a graph illustrating the relative yield of the D2 fraction according to the weight ratio of sodium bisulfite and defatted soybean in the present invention.

Claims (1)

[Scope of Claims] 1. A first step in which a soybean protein raw material containing soybean polysaccharides is treated in the presence of a sulfite compound, a glutathione compound, or a cysteine compound in an aqueous system with a pH of 6.5 or higher; A second step in which the temperature is lower than the treated pH and 5.5 to 7.0 and a temperature lower than the temperature treated in the first step and 20 ° C or less, and a third step in which the temperature is fractionated into a soluble fraction and an insoluble fraction. A method for producing soybean protein characterized by comprising: 2. The production according to claim 1, wherein the insoluble fraction fractionated in the first step, second step, and third step is further transferred to a hot water system to be dispersed or dissolved, and the dispersed or dissolved fraction is separated. Law. 3. The production according to claim 1, wherein the soluble fractions obtained in the first, second, and third steps are subjected to isoelectric point precipitation, the precipitated fractions are separated and collected, and after neutralization, heat treatment is performed and dried. Law.