JPH1070959A - Production of fractionated soybean protein and food using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fractionated soybean protein having low allergen, remarkably improved in color tone, taste, transparency and gel strength by treating soybean protein with an acid such as sulfuric acid and a specific aqueous solution, removing the resultant precipitate fraction and collecting the supernatant fraction. SOLUTION: Soybean protein is treated with an acid selected from sulfuric acid, acetic acid and citric acid and an aqueous solution having pH <=4, to which an alkaline earth metal salt or hydroxide is added so as to become 0-200mM and the resultant precipitative fraction is removed and the residual fraction is preferably treated with a reducing agent or under electric reduction and the supernatant fraction is collected and subjected to neutralization, desalting, removing of whey, heat-sterilization or drying to provide the objective fractionated soybean protein. Furthermore, foods using the soybean protein, obtained from the fractionated soybean protein are useful as low-allergen foods for allergic patients.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a low allergen,
The present invention relates to a method for producing a fractionated soybean protein having excellent color tone (brightness, transparency), flavor, and gel strength, and a low-allergen food using the same.

[0002]

2. Description of the Related Art In recent years, allergic patients such as atopic dermatitis patients have been increasing. In food, protein contained in egg white, soy, or milk is recognized as three major allergens,
A so-called elimination diet is introduced as a symptomatic treatment for them. However, among the above allergens, soy protein is contained in Japanese traditional foods such as tofu, fried tofu, frozen tofu and yuba or in a wide range of foods containing these as a part of the raw material. The recent situation in which foods utilizing functions such as properties, film forming properties, water retention, viscosity increase, foaming properties, etc. have been increasing in the past, makes it difficult to select foods in removal diet therapy. .

Ogawa et al. Identified Gly m Bd 30k as a soybean protein component highly reactive with IgE antibodies obtained from a patient with atopic disease against soybean [SDS-PAGE
It is a protein contained in a fraction showing a band with a molecular weight of about 34 kDa by electrophoresis.
"Gly m I" in this specification.
Or "allergen protein"), and this allergen protein is described in Than and Shibasaki (J. A.
gric. Food Chem., Vol. 24, 1117-1121, 1976) .These fractions were found to be almost absent in the 11S fraction and the whey fraction and more in the 7S fraction (Biosci. Biotech. Biochem. , 57
Vol. 1030, 1993).

However, as a result of various studies, the present inventors have found that a 7S fraction from which an allergen protein has been separated can be extremely easily obtained by treating a specific acid with an aqueous solution having a specific pH, and Further, it was found that the aqueous solution also contained a small amount of an alkaline earth metal salt, whereby the allergen protein was separated, and a fractionated soybean protein was obtained which was enriched in not only the 7S fraction but also the 11 fraction. The invention has been reached.

[0005] The inventor has also found that Gly m I
It has also been found that the soybean protein having reduced soybean protein has improved color, flavor and gel strength, and can be used in a variety of applications not limited to patients with allergy to soybean protein.

[0006] Separation and removal of the GlymI component from the 7S fraction by the above-mentioned reported method is extremely difficult industrially, aside from the laboratory, but rather, the 11S fraction. If only the protein of the fraction and the whey fraction is collected, the total amount is only 30-40% of the soymilk protein (25-30% for the 11S fraction only), so the yield as a low allergen protein is low. The problem is that the fractionation of the 7S fraction and the 11S fraction itself requires fine pH adjustment of soymilk and a long-term low-temperature treatment, or that the 7S protein contains If not included, the functionality would change considerably.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to produce a soybean protein having a low allergen, a good taste and a good color tone in an efficient manner, that is, with a high yield and a simple method.

[0008]

That is, the present invention provides:
The soybean protein is treated with an aqueous solution of pH 4 or less to which an acid selected from sulfuric acid, acetic acid, or citric acid and 0 to 200 mM of a salt or hydroxide of an alkaline earth metal are added, and the resulting sedimentable fraction is treated. A method for producing a fractionated soybean protein, which comprises removing the supernatant fraction and collecting a supernatant fraction, and a food using soybean protein using the fractionated soybean protein obtained by this method as a soybean protein component.

The treatment with an aqueous solution having a pH of 4 or less according to the present invention may be carried out in any manner as long as the soybean protein is exposed to the aqueous solution. Or a method in which a soluble fraction is extracted from an acid-precipitated soybean protein. However, if the pH is too low, the protein will be denatured, making it difficult to use the product depending on the purpose.
It is generally good not to drop below pH 2.0.

Then, "treatment with an aqueous solution of pH 4 or less"
Otherwise, separation is unlikely to occur even when high gravity is applied, and a large amount of allergen protein remains in the supernatant even if a slightly precipitated fraction is formed. In general, when the pH under acidic conditions is higher than 5, the effect of selectively improving the sedimentation of the allergen protein is poor.

As the acid to be used, sulfuric acid, acetic acid or citric acid must be contained, but not all acids for making the acidity of pH 4 or less may be used. In other words, it is sufficient that these acids are contained in such an amount that they occupy the majority of the weight. However, when these acids are small, the separability of the 7S protein and the allergen protein is reduced.

Further, depending on the concentration of the alkaline earth metal salt or hydroxide contained in the aqueous solution having a pH of 4 or less,
The yield of 11S protein in the fractionated soybean protein can be controlled.
That is, when there is no alkaline earth metal salt or the like contained in the aqueous solution or when the alkaline earth metal salt or the like is about 10 mM or less, as a fractionated soybean protein, the 7S protein from which the allergen protein and the 11S protein are separated Can be easily obtained. Further, as the amount of alkaline earth metal salt increases, the amount of 11S protein in the fractionated soybean protein increases, but the separability from allergen protein decreases temporarily (FIG. 1). 200 mM or less. From the viewpoints of the yield of the total storage protein and the separability of the allergen protein, the alkaline earth metal salt and the like are preferably 10 to 100 mM, and especially at 20 to 60 mM, other acids and other salts such as hydrochloric acid and citric acid It is possible to reduce the amount of allergen proteins equivalent to or higher than that of using alkali metal salts having polyvalent acid radicals such as sodium acid salt, sodium tartrate, sodium sulfate, etc., and to increase the yield of storage proteins. In addition, the conductivity of the liquid can be reduced, which is advantageous in operations such as desalination. Examples of the alkaline earth metal salt or hydroxide include calcium and magnesium chlorides, sulfates and hydroxides.

Examples of the raw soybean protein include soymilk extracted from soybean or defatted soybean, acid-precipitated soybean protein obtained by precipitating and separating soybean milk by adjusting its isoelectric point pH, and so-called separated protein obtained by neutralizing the soybean protein. Low-denatured, defatted, low-density protein helps to obtain the final target protein in good yield, and soybean protein, which is not twisted after harvesting, stably manages to a good yield. Easy to do.

However, even if the protein is denatured by being subjected to heat to some extent, or a so-called old crop raw material protein, a reducing agent such as a salt such as sodium bisulfite, cysteine, etc. is obtained before fractionated soybean protein is obtained. By using an SS bond cleavage agent or the like, or by treating soybean or soymilk in an electrically reduced state, it is useful to obtain the final target protein in good or stable yield.

An embodiment of obtaining an aqueous extract of soybean protein is, for example, defatted soymilk (pulverized soybean is defatted with hexane, and water is added. If necessary, the pH is adjusted to neutral or slightly alkaline, and the supernatant from which okara is removed is removed. ), If necessary, add salts, or dissolve the separated soy protein, which is a water-soluble protein, in water and add the salt thereto, or add water and an alkali or acid to the acid-precipitated soy protein, and dissolve the salt. In addition to the mode of addition, etc., the mode of extraction after dissolving salts may be used. The pH of the aqueous extract is preferably 6.5 or more,
It is more preferably neutral or slightly alkaline at least 7.0 or acidic at pH 2.0 to 4.0, more preferably 2.5 to 3.8. The aqueous extract can be selected from a range in which the concentration of solids in the aqueous medium is about 1 to 20% by weight, and the aqueous medium contains the above-mentioned salt and, if necessary, an emulsifier in water. You may.

The allergen protein GlymI can be selectively concentrated in the sedimentable fraction produced by the treatment of the above aqueous solution having a pH of 4 or less. -Collect the fraction containing soybean protein, which is excellent in flavor and gel-forming ability, as fractionated soybean protein. This fraction is tofu, tofu, frozen tofu,
It may be used as a raw material for processed soybean foods such as yuba, soymilk, miso, soy sauce, and soybean protein, and depending on the purpose, neutralization, desalting such as electrodialysis, heat sterilization, freeze drying, and spray drying. , Vacuum drying, hot air drying, etc., and in some cases, after desalting (desalting is unnecessary if the amount of salt used is small), adjust the pH to around the isoelectric point to remove whey. By preparing soy protein-containing foods, such as by using so-called acid precipitated protein or isolated soy protein, for example, by processing into fibrous protein or membrane protein, or by burying in fish and meat brick products Can be. They are not only useful as allergen-reduced foods for soy allergy patients or allergen-removed foods, but also as foods excellent in flavor and color.

[0017]

Embodiments of the present invention will be described below.

Example 1 (including comparison) 15 kg of water was added to 1 kg of low-denatured defatted soybean, and the mixture was diluted with 1N NaOH.
After adjusting the pH to 7.5 and performing stirring extraction at room temperature for 3 hours, defatted soymilk from which okara components were removed by centrifugation was obtained (this soymilk is hereinafter referred to as raw soymilk).

Calcium chloride was added to the raw soybean milk at various concentrations as shown in the following table, dissolved and stirred, and the pH was adjusted to 2.8 with 2N sulfuric acid.
The protein content in the supernatant fraction obtained by centrifugation for 10 minutes was measured by the Kjeldahl method, and the total protein in the raw soybean milk was determined by 10%.
The dissolution rate of the protein was determined as 0%. Also, dilute the supernatant fraction three-fold (however, if the amount of calcium chloride added is 50 mM or more, dilute it at a high magnification such that the amount of calcium chloride becomes about 5 to 10 mM so that subsequent isoelectric point precipitation is possible. )
Thereafter, the protein was adjusted to pH 4.5 with sodium hydroxide, subjected to isoelectric point precipitation, and the protein from which whey proteins had been removed by centrifugation was separated and developed into proteins of each composition by SDS-electrophoresis. And three proteins of Glym I (quantified as 34 kDa protein after removal of whey) by CBB
After protein staining, the peak areas determined by densitometry were determined, and the dissolution rate of each of the constituent proteins was defined as the following table, with the peak area of these constituent proteins as 100% when all proteins in the raw soybean milk were separated and developed, as shown in the following table. Figure 1
Also shown. As can be seen from the following table, the allergen protein could be reduced to less than half in the range of 0 to about 200 mM calcium chloride.

豆 ───── ──────────────────── Raw soy milk Concentration of calcium chloride added Protein dissolution rate 0 mM 10 mM 30 mM 50 mM 100 mM 300 mM 1000 mM ─────── ───── 質量 Supernatant protein content 100% 34% 45% 72% 75% 79 % 85% 90% SDS-electrophoresis 7S 100% 90% 92% 92% 92% 92% 92% 100% 11S 100% 5% 40% 81% 82% 88% 90% 90% Glym I 100% 1 % 7% 10% 16% 34% 65% 82% ─────── ───── ────────────────────

Further, the results shown in the following table were obtained in comparison with the case where sodium sulfate was used instead of calcium chloride and hydrochloric acid was used instead of sulfuric acid. ─────── ───── ───────────────── Raw soy milk Concentration of sodium sulfate added to soy milk Protein dissolution rate 0 mM 10 mM 30 mM 100 mM ── ───── ───── ───────── 質量 Supernatant protein mass 100% 95% 72% 60% 62% SDS-electrophoresis 7S 100% 95% 73% 70% 66% 11S 100% 90% 75% 59% 74% Glym I 100% 89% 41% 12% 8% ─────── ───── ──────────── ─────

As is apparent from the above comparison, since the acid is sulfuric acid, the added salt concentration is lower than 0 to 10 mM,
High 7S protein without allergen protein could be easily obtained. In order to obtain a fractionated soybean protein in which the allergen protein has been reduced to about 10%, sulfate-calcium chloride has a higher protein yield (supernatant protein mass) than hydrochloric acid-sodium sulfate, and , Low salt concentration,
It was excellent.

Example 2 Calcium chloride was added to the raw soybean milk obtained in the same manner as in Example 1 to a concentration of 30 mM, dissolved and stirred, and the pH was adjusted to 3.0 with 2N sulfuric acid. 000 × g,
The supernatant fraction obtained by centrifugation for 10 minutes is diluted three times (however, when the amount of calcium chloride added is 50 mM or more, the amount of calcium chloride is 5 to 10 mM so that subsequent isoelectric focusing can be performed). After dilution at high magnification)
Adjusted to 4.5 with sodium hydroxide and isoelectrically precipitated,
The card was obtained by centrifugation. The curd was appropriately watered, neutralized with sodium hydroxide, sterilized by heating, and spray-dried to prepare an isolated soybean protein. At this time, the recovery rate of the protein was 50% of the soymilk protein.

Example 3 An isolated soybean protein was prepared in the same manner as in Example 2 except that the concentration of calcium chloride was changed to 10 mM. At this time, the protein recovery was 33% of the soymilk protein.

Comparative Example 1 An isolated soybean protein was prepared in the same manner as in Example 2 except that the concentration of calcium chloride was changed to 300 mM. At this time, the recovery rate of the protein was 70% of that of the soymilk protein.

Comparative Example 2 The raw soybean milk obtained in the same manner as in Example 1 was adjusted to pH 4.5 with sulfuric acid without adding any salt, and subjected to isoelectric point precipitation, followed by centrifugation to obtain a curd. . The curd was appropriately watered, neutralized with sodium hydroxide, sterilized by heating, and spray-dried to prepare an isolated soybean protein. At this time, the protein recovery was 88% of the soymilk protein.

As shown in the following table, a paste of 17% was prepared for each of the four kinds of separated soybean proteins, filled in a plastic casing having a folding width of 37 mm, and heated at 80 ° C. for 30 minutes to perform sensory evaluation of the gel and Leona. (By Yamaden Corporation). Color (bright / 10 points to dark / 1 point), transparency (transparency / 10 points to opaque / 1)
20 panelists conducted sensory evaluations of the quality of the three items: taste) (no taste / 10 points to bad / 1 point), and the average value was shown. As a result, Examples 1 and 2 showed good results in color, flavor and transparency as compared with Comparative Examples 1 and 2 and also exhibited high ballistic strength and strong gel-forming ability.

────────────────────────────────── Isolated soy protein Color Transparency Flavor Impact strength (g × cm ) ────────────────────────────────── Example 2 6.2 6.8 7.3 754 Example 3 8.9 8.7 8.5 645 Comparative Example 1 4.7 4.3 5.6 550 Comparative Example 2 4.5 4.0 5.1 5.1 345 ─────────────────────

Example 4 Separated proteins were prepared in the same manner as in Example 2 except that acetic acid was used instead of sulfuric acid. At this time, the recovery of the protein was 61% of that of the soymilk protein, and both the color and the flavor were clearly superior to those of Comparative Example 2.

Example 5 15 g of water was added to 1 kg of low-denatured defatted soybean, the pH was adjusted to 9.0 with calcium hydroxide, and the mixture was stirred and extracted at room temperature for 1 hour. I got soy milk. After adding calcium chloride to this soymilk to 20 mM, the pH of the soymilk was adjusted to 3.0 with 2N sulfuric acid, and the supernatant fraction obtained by centrifugation at 10,000 × g for 10 minutes was added to 3 ml of the supernatant fraction. After diluting twice, the pH was adjusted to 4.5 with sodium hydroxide, and the solution was subjected to isoelectric point precipitation, followed by centrifugation to obtain a curd. The curd was appropriately watered, neutralized with sodium hydroxide, sterilized by heating, and spray-dried to prepare an isolated soybean protein. At this time, the recovery rate of the protein was 50% of that of the soymilk protein, and both the color and the flavor were clearly superior to those of Comparative Example 2.

[0031]

As described above, according to the present invention, a fractionated soybean protein having a low allergen and a markedly improved color, flavor, transparency and gel strength can be produced in a high yield and a simple method. be able to. This fractionated soy protein can be used as a high-quality protein source for soy allergy patients who have been difficult to supply the protein by the conventional dietary therapy.

[Brief description of the drawings]

 (

1] FIG. 1 is a graph showing the dissolution rates of 7 types of proteins, 7S, 11S, and GlymI, with respect to each concentration of calcium chloride in Example 1.

Claims (8)

[Claims] 1. A soybean protein is treated with an aqueous solution having a pH of 4 or less to which an acid selected from sulfuric acid, acetic acid, or citric acid and an alkaline earth metal salt or hydroxide are added so as to have a concentration of 0 to 200 mM. And removing the resulting sedimentable fraction, and collecting the supernatant fraction. 2. An embodiment in which the soybean protein is treated with an aqueous solution having a pH of 4 or less, wherein a sedimentable fraction is formed from an aqueous extract of the soybean protein, or a soluble fraction is extracted from the acid-precipitated soybean protein. 2. The method according to claim 1, wherein the method is any of the above. 3. The process according to claim 1, wherein the pH to be treated is 2 to 4, the alkaline earth metal salt concentration during the treatment is 0 to 20 mM, and the fractionated soybean protein obtained is 7S soybean protein. 4. The treatment is carried out at a pH of 2 to 4, and the concentration of an alkaline earth metal salt or hydroxide at the time of treatment is from 20 to 1.
2. The method according to claim 1, wherein the concentration is 00 mM. 5. In a step before collecting a supernatant fraction,
The method according to any one of claims 1 to 4, wherein the soy protein is treated under a reducing agent or electric reduction. 6. The production method according to claim 1, wherein the collected supernatant fraction is neutralized, desalted, dewheyed, sterilized by heating or dried. 7. A food using soy protein, wherein the soy protein component is derived from the fractionated soy protein obtained by the production method according to any one of claims 1 to 6. 8. The food containing soy protein according to claim 7, which is a food with reduced allergen for soy allergy patients.