JP2789840B2 - Method for producing foamable soy protein - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a foamable soybean protein used as a foaming agent in the field of food production. The present invention relates to a method for producing a foamable soybean protein having stability and foam retaining properties, and having excellent color tone and flavor.

[0002]

2. Description of the Related Art It has been known that a soybean protein partially hydrolyzed by a protease has a foaming property. The foamable soybean protein obtained by partial hydrolysis in this way has been used as a foaming agent in various food production fields.

[0003] In producing the above-mentioned foamable soybean protein, US Pat. Nos. 2,489,173, 2,502,029, 3,814,816, and Japanese Patent Application Laid-Open No.
The method disclosed in JP-A-9-109551 or the like has been generally known. Here, the methods shown therein generally use defatted soybeans as a raw material, hydrolyze the defatted soybeans with a protease, remove the insoluble fraction, and extract only the soluble fraction. Was.

[0004] However, the foamable soybean protein produced in this manner has poor color tone and flavor, and has insufficient foaming properties. When used as a foaming agent in various foods, sufficient foaming properties are not obtained. There were problems such as a lack of foaming power, a blue odor peculiar to the soybean, and a change of the food to brown.

[0005] The foamable soybean protein produced as described above is insufficient in foaming power, foaming stability and foam retention, especially in an oil-containing system. However, there is a problem that it is not suitable for producing foods to be foamed under an oil-containing system such as whipping cream, nougat, marshmallow, frappe and the like.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in a foamable soybean protein obtained by partially hydrolyzing a soybean protein.

That is, the present invention has excellent foaming power, foaming stability and foam retention under water-based and oil-containing systems, and also has a good color tone and flavor. It is an object of the present invention to provide a foamable soybean protein which can be suitably used in confectionery which is foamed under an oil-containing system such as castella, fresh confectionery for cakes and the like.

[0008]

In the present invention, in order to solve the above-mentioned problems, a solution in which soybean protein is dissolved in an aqueous salt solution is extracted in an acidic region, and the soluble fraction is subjected to protease. It was made to hydrolyze.

Here, as the soybean protein, defatted soybean, concentrated soybean protein and the like can be used, but in order to enhance the flavor and color tone of the foamable soybean protein obtained, defatted soybean is extracted with hot water. Then, it is preferable to use an isolated soybean protein from which the whey component has been removed by isoelectric focusing at around pH 4.5.

As the aqueous salt solution for dissolving the soybean protein, an aqueous solution of a sodium salt, a potassium salt or the like can be used. Then, after dissolving the soybean protein in such an aqueous salt solution, when extracting the soluble fraction in the acidic region, if the ionic strength of the aqueous salt solution is too weak, the fraction that adversely affects the foaming property may be reduced. On the other hand, if the concentration of the aqueous salt solution is too high, the extraction of the soluble fraction becomes difficult and the yield becomes poor, so that the ion concentration of the aqueous salt solution is reduced to 0.05 to 1.0 mol. It is preferable that the adjustment be made.

When the soluble fraction is extracted in the acidic region from the aqueous salt solution in which the soybean protein is dissolved as described above, if the pH is too high or too low, the foaming property is adversely affected. Since the fraction is extracted as a soluble fraction, it is preferably adjusted so that its pH is in the range of 2.0 to 5.0, more preferably its pH is in the range of 3.0 to 3.5. I do.

When the soluble fraction is extracted as described above, if the temperature of the aqueous salt solution is too low, the extraction of the soluble fraction becomes difficult and the yield becomes poor. If it is too much, a fraction that adversely affects the foaming property will be extracted as a soluble fraction, so that the temperature of the salt aqueous solution is preferably 5 to 50 ° C, more preferably 20 to 30 ° C. adjust.

When the soluble fraction thus obtained is hydrolyzed with a protease, known proteases can be used. In order to reduce the bitterness of the protein, it is preferable to use an endo-type protease as the proteolytic enzyme, and it is particularly preferable to use pepsin.

In the case where the soluble fraction extracted as described above is hydrolyzed by a protease, if the decomposition rate is too high, the amount of low-molecular-weight ones becomes too large, and so When the foaming stability is deteriorated and the decomposition rate is low, the foaming power of the foamable soybean protein is low when the decomposition rate is low, and the foaming power of the foaming soybean protein is deteriorated. (The ratio of the protein dissolved in the acetic acid aqueous solution) to 40 to 80%, more preferably 60 to 70%.

After the soluble fraction is hydrolyzed with a protease as described above, the protease is inactivated and then dried by spray drying or the like to produce foamable soybean protein. I do. Here, when inactivating the protease, the pH of the hydrolyzed solution is usually adjusted to 2.0.
To 7.0, preferably 2.0 to 5.5, more preferably 2.0 to 3.5. By doing so, the foaming heat stability of the produced foamable soybean protein is improved. In the case of drying by spray drying or the like, it is desirable to adjust the pH in the range of 5.0 to 6.0.

[0016]

When the foamable soybean protein is produced as in the present invention, components such as whey which impair the flavor and color tone are removed and the foaming power, foaming stability and foam retention are improved. Fractions that have an adverse effect are also removed, and have excellent foaming power, foaming stability and foam retention under aqueous and oil-containing systems, as well as foaming soy protein with good color and flavor. Can be obtained.

In particular, in the case of producing foamable soybean protein as described above, the pH of the soluble fraction is adjusted to 3.0 to 6.0 before drying by spray drying or the like. By removing the precipitate generated at that time, the foaming heat stability in the foamable soybean protein is improved, for example, without foaming even if a starch syrup at about 130 ° C. is added to the foamed soybean protein. The foaming state is stabilized.

[0018]

EXAMPLES Examples of the method for producing a foamable soybean protein according to the present invention will be specifically described below, and comparative examples will be given. The foamable soybean protein produced according to the example of the present invention is excellent. Make it clear.

Example 1 In this example, 20 liters of hot water at 40 ° C. was added to 2 kg of defatted soybean flakes manufactured by Fuji Oil Co., Ltd., and a 5N sodium hydroxide solution was added thereto to adjust the pH. The mixture was adjusted to 7.0, gently stirred for about 1 hour to perform extraction, and the extract was centrifuged to remove the insoluble fraction, and the soluble fraction was collected.

Then, hydrochloric acid was added to the soluble fraction thus collected to adjust its pH to 4.5, and the resulting protein precipitate was collected by a centrifuge, and the soybean thus collected was collected. After water was added to the protein precipitate to suspend it well, the soy protein precipitate was collected again using a centrifuge to obtain a separated soy protein curd. In this isolated soybean protein curd, the solid content was 30% by weight, and the crude protein purity in the solid content was 96% by weight.

Next, using the isolated soybean protein curd thus obtained, a solution containing 10% by weight of the isolated soybean protein was prepared, and 58.4 g of sodium chloride was added to 2 liters of this solution. The pH was adjusted to 3.5 using hydrochloric acid, and the mixture was stirred at 20 ° C. for about 1 hour to perform extraction. The extract was centrifuged and separated into a soluble fraction and an insoluble fraction. Fractions were collected.

The soluble fraction collected in this manner is
The pH was adjusted to 4.5 by addition of defined sodium hydroxide, and the resulting soybean protein precipitate was collected by a centrifuge.

Next, water and hydrochloric acid were added to the soybean protein precipitate thus collected to obtain a solution 400 having a pH of 2.0.
ml was prepared, and 10,000 units of 141 mg of pepsin (manufactured by Wako Pure Chemical Industries) was added thereto, and partial hydrolysis was carried out at 50 ° C. for about 3 hours.

Then, the partial hydrolyzate thus obtained is heated at 80 ° C. for 1 hour in an acidic region of pH 2.0 to inactivate the enzyme, and then 5N sodium hydroxide is added. The pH was adjusted to 5.0 and then spray dried to give 32 g of foamable soy protein.

Comparative Example 1 In this comparative example, foamable soybean protein was produced according to the method described in US Pat. No. 3,814,816.

In this comparative example, 20 liters of hot water at 30 ° C. was added to 2 kg of defatted soybean flakes manufactured by Fuji Oil Co., Ltd., and a 5N sodium hydroxide solution was added to adjust the pH to 7.0. Then, the mixture was gently stirred for about 1 hour to perform extraction. The extract was centrifuged to remove insoluble fraction, and a soluble fraction was collected.

Then, the soluble fraction collected in this way was
The mixture was heated to 0 ° C., 20 g of 35% hydrogen peroxide solution was added thereto with rapid stirring, and the mixture was allowed to stand for 10 minutes. After that, the pH was adjusted to 8.5 with 5N sodium hydroxide, and then the mixture was added to 80%. Stirred gently at 30 ° C for 30 minutes.

Next, 10% sulfuric acid was added thereto to adjust the pH to 4.4, and the resulting soybean protein precipitate was collected by a centrifuge, and 20 liters of water was added to the soybean protein precipitate. The soybean protein precipitate was collected by centrifugation again to obtain a soybean protein curd. The soy protein curd thus obtained has a solid content of 28%.
96% by weight crude protein purity in solids
Met.

Then, the soy protein curd 2.43 kg
Water and hydrochloric acid were added to the mixture to adjust the pH to 1.3
A solution of 2.38 g of pepsin (manufactured by Wako Pure Chemical Industries, Ltd.) in 20 ml of water was added to this solution, and the mixture was stirred at 30 ° C. for 20 hours.
The stirring was performed for 4 hours after the addition of the above-mentioned pepsin, and thereafter, the stirring was performed for 1 hour every 3 hours. During the stirring, the pH was always kept between 1.3 and 1.8.

After partially hydrolyzing the soybean protein with the above-mentioned pepsin in this manner, the soybean protein is heated at 70 ° C. for 1 hour to inactivate the above-mentioned enzyme. Was adjusted to 5.0 to precipitate an insoluble fraction.

Then, the insoluble fraction thus precipitated was removed by a centrifugal separator, and the hydrolyzate was spray-dried to obtain a foamable soybean protein.

Comparative Example 2 In this comparative example, foamable soybean protein was produced according to the method disclosed in Japanese Patent Application Laid-Open No. 49-109551.

In this comparative example, hydrochloric acid was added to 5 liters of a solution containing 6% by weight of isolated soybean protein to adjust the pH to 1.5, and then 10,000 units of pepsin (total) were added thereto. 130 g)
Partial hydrolysis was performed at 40 ° C. for 24 hours.

Then, 5N sodium hydroxide was added to the hydrolyzate to adjust its pH to 4.5.
After heating the mixture for 30 minutes to deactivate the enzyme, the insoluble fraction was removed using a centrifuge, and the soluble fraction was collected.

Next, the pH of the soluble fraction was adjusted to 8.5 by adding 5N sodium hydroxide, and the resulting precipitate was removed by a centrifugal separator. In addition, the pH was adjusted to 6.5 and then spray-dried to obtain a foamable soybean protein.

Next, the foaming properties of the foamable soybean proteins of Example 1 and Comparative Examples 1 and 2 produced as described above in an aqueous system and an oil-impregnated system were measured. The foam stability was measured, and the hardness, color tone and flavor of the foam were examined. The results are shown in Table 1 below.

When measuring the foaming properties in an aqueous system, the foaming soybean proteins of Example 1 and Comparative Examples 1 and 2 were added to water, and each of the foamable soybean proteins was 5% by weight. 100 ml of the resulting aqueous solution was prepared, and the homogenizer (manufactured by Nippon Seiki Co., Ltd.) was used at 10,000 rpm.
, And transferred to a measuring cylinder to measure the volume (ml) of the generated foam. on the other hand,
For the foaming property under an oil-containing system, an aqueous solution containing 15% by weight of oil was used in place of the water, and the foam volume (m
1) was measured.

As to the foaming stability under the oil-containing system, the foaming capacity (ml) after 1 hour and 2 hours was measured for each of the foams under the oil-containing system as described above. I did it.

[0039]

[Table 1]

As is clear from the results, the foamable soybean protein of Example 1 is more foamable and foamable under an oil-containing system than the foamable soybean proteins of Comparative Examples 1 and 2. The foaming properties were particularly excellent, and the foam was also excellent in terms of hardness color tone and flavor as compared with the foamable soybean proteins of Comparative Examples 1 and 2.

(Examples 2 to 5 and Comparative Example 3) In these examples, the influence of the ionic strength of the aqueous salt solution for dissolving the soybean protein was examined.

Here, in Examples 2 to 5 and Comparative Example 3, a solution containing 10% by weight of isolated soybean protein was used. When adding sodium chloride to this solution, the ionic strength is 0.05 mol in Example 2, 0.1 mol in Example 3, 0.5 mol in Example 4, and 0.5 mol in Example 6. 1.
While adjusting to 6 mol, in Comparative Example 2, sodium chloride was not added.

Then, the thus prepared products were adjusted to pH 3.5 by adding hydrochloric acid, respectively.
This was stirred at 20 ° C. for 1 hour, and then fractionated into a soluble fraction and an insoluble fraction using a centrifuge, and a soluble fraction was collected.

Next, sodium hydroxide was added to each of the soluble fractions thus collected, the pH thereof was adjusted to 4.5, and the solution was subjected to isoelectric point precipitation. The precipitate was recovered, and water was added thereto. Was added to prepare a solution having a concentration of 10% by weight.

After adjusting the pH to 2.0 by adding hydrochloric acid to each solution thus prepared, 10,000 units of pepsin were added to the crude protein in the solution at a concentration of 0.1 unit.
The mixture was added at a rate of 35%, heated to 50 ° C., and partially hydrolyzed for 3 hours.

Next, each hydrolyzate thus obtained was heated at 80 ° C. for 30 minutes to inactivate the pepsin, and then sodium hydroxide was added thereto to adjust the pH to 5.
5, and then spray-dried to produce each foamable soybean protein.

The extraction yield of each of the foamable soybean proteins of Examples 2 to 5 and Comparative Example 3 thus produced was determined. And the foaming stability under an oil-containing system and the foam hardness were measured, and the results are shown in Table 2 below.

[0048]

[Table 2]

As is apparent from the results, the foaming soybean proteins of Examples 2 to 5 in which salts were added to soybean protein to perform extraction were the foaming properties of Comparative Example 3 in which no salt was added. Compared with soybean protein, foaming property and foaming stability under an oil-containing system were particularly excellent, and foam hardness was also high.

(Examples 6 to 11) In these examples, the effect of pH on extracting a solution in which a soybean protein was dissolved in an aqueous salt solution in an acidic region was examined.

In these examples, sodium chloride was added to a solution containing 10% by weight of isolated soybean protein to adjust its ionic strength to 0.5 mol, and then hydrochloric acid was added to adjust the pH. I did it. Here, in Example 6, the pH was 2.0, and in Example 7, the pH was p.
H was 3.0, Example 8 had a pH of 3.5, Example 9 had a pH of 3.75, and Example 10 had a p of
H was adjusted to 4.5, and in Example 11, the pH was adjusted to 5.5.

Thereafter, these were used to produce each foamable soybean protein in exactly the same manner as in Examples 2 to 5 above.

The extraction yield of each of the foaming soybean proteins of Examples 6 to 11 thus produced was determined, and the foaming properties under water and oil-containing systems were determined in the same manner as described above. The foaming stability and foam hardness under an oil-containing system were measured, and the results are shown in Table 3 below.

[0054]

[Table 3]

As is apparent from the results, when extracting a solution obtained by dissolving soybean protein in an aqueous salt solution in the acidic region, the pH was adjusted to a range of 3.0 to 4.5. A hard foaming soybean protein having excellent foaming properties and foaming stability and foam hardness was obtained.

(Examples 12 to 17) In these examples, the influence of temperature upon extracting a solution obtained by dissolving soybean protein in an aqueous salt solution in an acidic region was examined.

In these examples, sodium chloride was added to a solution containing 10% by weight of isolated soybean protein to adjust the ionic strength to 0.5 mol, and hydrochloric acid was added to this solution to adjust the pH. Adjusted to 3.5.

Each of the solutions thus prepared was subjected to 5 ° C. in Example 12 and 10 ° C. in Example 13.
° C, 20 ° C in Example 14, 30 ° C in Example 15, 40 ° C in Example 16, and 50 ° C in Example 17.

Thereafter, each foamable soybean protein was produced in exactly the same manner as in Examples 2 to 5.

Then, the extraction yield of each of the foamable soybean proteins of Examples 12 to 17 thus produced was determined, and in the same manner as described above, the foaming properties under aqueous and oil-containing systems were determined. The foaming stability and the foam hardness under an oil-containing system were measured, and the results are shown in Table 4 below.

[0061]

[Table 4]

As is evident from the results, when extracting a solution obtained by dissolving soybean protein in an aqueous salt solution in an acidic region, increasing the temperature at the time of extraction improves the extraction yield while improving the foaming property. However, since the foaming stability and foam hardness are reduced, and if the temperature is too low, the extraction efficiency is significantly reduced, it is preferred that the above-mentioned extraction be performed at a temperature of 20 to 30 ° C. Was.

[0063]

As described above in detail, in the method for producing foamable soybean protein according to the present invention, the soybean protein is dissolved in an aqueous salt solution, and the aqueous salt solution in which the soybean protein is dissolved is subjected to an acidic treatment. In order to extract the soluble fraction and hydrolyze the extracted soluble fraction with proteolytic enzymes, components such as whey that impair the flavor and color tone are removed, and the foamable soybean protein is removed. Fractions that adversely affect the foaming power, foaming stability, foam retention, etc. are also removed. Excellent foaming power, foam stability, foam retention under water and oil-containing conditions. A foamable soybean protein having good properties and color tone and flavor can be obtained.

As a result, the foamable soybean protein obtained according to the present invention can be effectively used for various foods, and is particularly foamed under oil-containing conditions such as castella, cake confectionery, whipped cream, nougat and marshmallow. In the production of confectionery and the like, they can be suitably used as these foaming agents.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-176549 (JP, A) JP-A-59-166040 (JP, A) JP-A-53-58981 (JP, A) 12588 (JP, B1) (58) Field surveyed (Int. Cl. ⁶ , DB name) A23J 1/00-7/00

Claims (4)

(57) [Claims] 1. A method for producing foamable soybean protein, comprising extracting a solution obtained by dissolving soybean protein in an aqueous salt solution in an acidic region, and hydrolyzing a soluble fraction thereof with a protease. 2. The ionic strength of the aqueous salt solution is 0.05.
The method for producing a foamable soybean protein according to claim 1, wherein the amount is from 1.0 to 1.0 mol. 3. Extraction of a solution obtained by dissolving soybean protein in an aqueous salt solution, the pH of the solution is adjusted to 2.0 to 5.0 and the temperature is adjusted to 5 to 50 ° C. The method for producing a foamable soybean protein according to claim 1 or 2, wherein the method is adjusted. 4. The degradation rate of said protease is determined by TCA
The foaming soybean according to any one of claims 1 to 3, wherein the solubility (the proportion of the protein dissolved in a 5% aqueous solution of trichloroacetic acid) is adjusted to a range of 40 to 80%. Method for producing protein.