JP3289770B2 - Proteolysate and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a specific component protein low-content proteolysate obtained by selectively decomposing a specific component protein among proteins containing a plurality of component proteins, and more particularly to a soy protein protein. The present invention relates to a glycinin-low content soybean protein hydrolyzate obtained by selectively decomposing glycinin, which is a main component of the above, and a method for producing the same.

[0002]

2. Description of the Related Art Soybeans contain many high-quality proteins and have been used as an excellent protein material since ancient times. In particular, isolated soy protein is useful as an excellent food material because it has a high protein content and various functional properties such as emulsifying properties, gelling properties, and water retention properties.

[0003] Soybean protein is composed of various proteins having a complicated high-order structure of a polymer. For example, in the method of fractionation based on the difference in sedimentation coefficient of ultracentrifugation, so-called 2S, 7
The proteins are classified into proteins such as S, 11S, and 15S, and these proteins also have different characteristics in physical properties.

[0004] For example, isolated soybean proteins obtained by acid precipitation of soymilk extracted with water from defatted soybeans are mainly composed of 7S globulin (mainly β-conglycinin) and 11S globulin (mainly glycinin). It has the following functional characteristics. However, in actual use, since the mixture is a mixture of these components, the inherent functional characteristics of each component are not sufficiently utilized.

[0005] Therefore, many attempts have been made to fractionate each component in order to utilize the inherent function of each component. For example, examples of research and reports on laboratory fractionation methods of Wolf et al. And Tan et al., JP-A-48-56843, and JP-A-49-3
1843, JP-A-51-86149, JP-A-55-124457, JP-A-55-15356
No. 2, JP-A-56-64755, JP-A-57-64755
JP-A-132844 and JP-A-58-36345 have been proposed. However, all of these methods are inevitable in a laboratory method and are unsuitable as industrial fractionation methods.

Japanese Patent Application Laid-Open No. 61-187755 proposes a method in which a soybean protein component can be fractionated by an industrial separation method by controlling pH and temperature in the presence of a sulfite compound or the like. Also requires complicated control of pH and temperature.

[0007] On the other hand, many studies have been made on functional improvement utilizing enzymatic degradation by a protease. For example, JP-B-48-24262, JP-B-55-1028, JP-A-62-232341, and JP-B-4-14.
No. 941 and the like, all of which are related to modification of functions such as solubility and non-gelling property by heating denaturation of soy protein in advance for enzymatic degradation to promote the degradation, and specific components of soy protein. No attempt has been made to modify the function to decompose only the chitin.

[0008] Proteins are generally insoluble in hydrolyzing enzymes, such as proteases, in their native state, as are soy proteins. (SS Nielsen et. A
l., J. Agric. Food Chem., 36, 869 (1988))
It is common knowledge to carry out heating and protein denaturation treatment such as alcohol upon decomposition.

As described above, the isolated soybean proteins mainly contain 7S globulin (mainly β-conglycinin) and 11S globulin.
It is a mixture composed of S globulin (mainly glycinin), and it is known that the degree of denaturation of each component due to external influence differs between the two. For example, it is known that 11S globulin is more easily denatured than 7S globulin at acidic pH. (I. Koshiyama, J. Sci. Fd Ag
ric., 23 , 853 (1972)) It is also known that the denaturation temperature of 7S globulin is lower than that of 11S globulin, and denaturation occurs at a lower heating temperature. (S. Damodaran, J.
Agric. FoodChem., 36 , 262 (1988)) However, the conventional method of enzymatic digestion may be to decompose the protein by excessive heating or alcohol denaturation, which is difficult to control. Only could not be decomposed selectively.

Therefore, if only specific components of soybean protein can be decomposed, soybean protein having unique functional characteristics can be obtained from a mixture in which each component is mixed.

[0011]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention relates to a method for producing a low-content proteolysate of a specific constituent protein, and more particularly, to a low-glycinin content in which glycinin, which is a main component of soybean protein, is selectively degraded. An object of the present invention is to provide a soybean protein degradation product and a method for producing the same.

[0012]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, have noticed that proteins containing a plurality of constituent proteins have different denaturation degrees under specific denaturing conditions. However, it has been found that a protease having a low content of a specific constituent protein can be obtained by acting a protease under the denaturing conditions. The term "protein containing a plurality of constituent proteins" as used herein refers to a protein comprising proteins having different physicochemical properties and being separable by a known separation and purification method, and is generally milk protein, meat protein, grain protein. For example, cereal proteins are further classified into soy protein, wheat protein, rice protein, etc., and among them, glycinin and β-conglycinin are known as main components as described above. I have. These in glycinin and β- conglycinin soy protein, for example, different modified about particular the acidic pH glycinin and β- conglycinin, glycinin low glycinin by acting a proteolytic enzyme was decomposed selectively in the pH Including
A quantity of protein degradation products is obtained.

[0013] That is, the present invention provides a method for producing a specific component protein low-content protein degradation product obtained by selectively degrading a specific component protein by acting a proteinase on a protein containing a plurality of component proteins. A method comprising reacting a protein containing a plurality of constituent proteins consisting of a denatured specific constituent protein and other constituent proteins under conditions in which the specific constituent protein is selectively denatured, wherein the denaturing condition is pH adjustment. And / or by adjusting the temperature. Low specific constituent protein
For protein degradation products, the degradation rate of specific constituent proteins
The degradation rate of main constituent proteins other than the specific constituent proteins is 60% or more, preferably 80% or more, and the degradation rate of the main constituent proteins is 40% or less, preferably 20% or less.

Further, the present invention is a method for producing a protein degraded with a low content of a specific constituent protein, which is obtained by allowing a proteinase to act on a soy protein to selectively degrade the specific constituent protein in the soy protein. As the specific constituent protein, the protease is adjusted to pH 1.0 to 2.8 with glycinin, preferably pH 1.0 to 2.8.
It is performed under 1.5-2.5.

Hereinafter, the present invention will be described in detail. As the protein containing a plurality of constituent proteins applied to the present invention, it is necessary to include a plurality of constituent proteins whose degree of denaturation is different among the constituent proteins under specific denaturing conditions, such as milk protein, meat protein, and cereal. And soybean protein, wheat protein, rice protein and the like. Proteins containing a plurality of these constituent proteins are not preferably those that have undergone excessive protein denaturation prior to specific denaturation conditions, and it is preferable to use a protein processed product that does not accompany or is slightly protein denatured. It is sufficient that the degree of denaturation is different between constituent proteins under specific denaturation conditions, in other words, when a protease is allowed to act.

The proteolytic enzyme treatment of a protein containing a plurality of constituent proteins is performed under conditions in which specific constituent proteins are selectively denatured. The conditions under which the specific constituent protein is selectively denatured vary depending on the constituent protein and cannot be specifically defined, but physicochemical conditions such as pH, temperature, ionic strength, pressure, and a chemical denaturant can be exemplified. Conditions using a plurality of combinations are also possible. Glycinin low content soy protein hydrolyzate will be described in detail. A processed soybean protein product which is not denatured or is slightly modified with a protein is preferably used, and is not limited to varieties, production areas, and the like. In general, defatted soybeans which have been subjected to a low-temperature extraction treatment using n-hexane as an extraction solvent are suitable as starting materials. preferable. Skim soybean milk, concentrated soybean protein, and isolated soybean protein that are extracted from such low-denatured defatted soybeans with water are preferably used in the present invention.

The protease used in the present invention has a pH of
It is necessary that the enzyme preparation has a proteolytic activity in the range of 1.0 to 2.8. These are not particularly limited in source such as commercially available enzyme preparations derived from plant or animal organs or microorganisms, but pepsin is most preferably used.

In practicing the present invention, the protease is
During the soy protein production process, added to soy protein, pH 1.0
Perform selective decomposition of glycinin at ~ 2.8. For example, when producing an isolated soybean protein, low-denatured defatted soybeans are extracted with water, separated into a water-insoluble fraction (okara) and a water-soluble fraction (soymilk), and the water-soluble fraction is subjected to isoelectric focusing. And separated into a water-insoluble fraction (curd) and a water-soluble fraction (whey) to obtain an acid-precipitated curd.
Adjust to 1.0-2.8 to perform decomposition reaction. Then, the reaction product is neutralized, sterilized, and dried for production. Alternatively, the reaction product is acid precipitated at around pH 4.8, which is the isoelectric point of β-conglycinin, and separated into a supernatant (mainly decomposed glycinin) and a precipitate (mainly undecomposed β-conglycinin) by centrifugation. Then, each of them can be manufactured by neutralizing, sterilizing, and drying.

Usually, the proteolytic enzyme adjusts the pH of an aqueous suspension containing undenatured soybean protein to 1.0 to 2.8, and preferably 0.001 to 0.5%, preferably 0.001 to 0.5%, based on the solid content of the aqueous suspension. Is
Enzyme reaction may be carried out by adding in the range of 0.01 to 0.1%. The reaction temperature is generally in the range of 20 to 50 ° C,
Preferably, the range is 30 to 40 ° C. Also, usually 5
The reaction may be carried out for a period of about 1 minute to 2 hours, preferably about 10 minutes to 30 minutes. By passing the solution through a column filled with the immobilized enzyme, continuous treatment can be performed.

The change of each component in the soybean protein due to the enzymatic degradation can be easily examined by separating each component by SDS-electrophoresis and checking the density of the band stained with Coomassie blue. According to the present invention, the degradation rate of glycinin is 60
% Or more, preferably 80% or more, and the β-conglycinin degradation rate is 40% or less, preferably 20% or less, in other words, the glycinin content is 40% or less, preferably 20%, of that of the raw soybean. And β-
A glycinin-low content soybean protein hydrolyzate having a conglycinin content of at least 60%, preferably at least 80% of that of the raw soybean can be easily obtained. The glycinin-low content soybean protein hydrolyzate thus obtained is effectively used as a food material utilizing the function of β-conglycinin.

[0021]

The present invention will be described below in more detail with reference to examples. However, the technical scope of the present invention is not limited to these examples.

Example 1 Low-denatured defatted soybean obtained using n-hexane as an extraction solvent (nitrogen solubility index; NS)
I> 80) 10 times the amount of water was added to 100 g,
After extraction at pH 7.0 for 1 hour, the mixture was centrifuged to obtain 950 g of defatted soymilk. Hydrochloric acid is added to 950 g of the defatted soy milk,
The pH was adjusted to 4.5, and centrifugation was performed to remove the whey fraction to obtain 100 g of an acid precipitated card. Hydrochloric acid was added to the aqueous suspension prepared by adding 100 g of the acid-precipitated curd to adjust the pH to 2.5, and 0.05% pepsin (manufactured by Sigma) based on the amount of dry matter was added.
An enzyme reaction was performed at 7 ° C. for 30 minutes. After neutralizing the enzyme reaction product with caustic soda, the solution heated at 140 ° C. for 15 seconds was spray-dried to obtain 37 g of soybean protein (test section). As a control, an aqueous suspension of the acid precipitation curd was neutralized with caustic soda.
A solution heated at 15 ° C. for 15 seconds and spray-dried was prepared (control).

[0023] Ten micrograms of each sample in the test group and the control group were separated by SDS-electrophoresis, and after coomassie blue staining, the density of the band was examined with a densitometer. The glycinin and β-conglycinin contents of the control were 100
%, The percentage reduction of each component in the test plot was determined.
It is as shown in Table 1. From this result, it can be seen that almost only glycinin in the soybean protein was selectively degraded.

Example 2 Hydrochloric acid was added to an aqueous suspension prepared by hydrolyzing an acid precipitation curd prepared in the same manner as in Example 1 to adjust the pH to 2.0.
, Pepsin (manufactured by Sigma) at 0.05% per dry matter was added, and the enzyme reaction was carried out at 37 ° C for 30 minutes. After neutralizing the enzyme reaction product with caustic soda, the solution heated at 140 ° C. for 15 seconds was spray-dried to prepare soy protein.

Example 3 Hydrochloric acid was added to an aqueous suspension prepared by hydrolyzing an acid precipitation curd prepared in the same manner as in Example 1 to obtain a pH 2.8.
And pepsin (manufactured by Sigma) at 0.05% per dry matter was added, and the enzyme reaction was carried out at 37 ° C. for 30 minutes. After neutralizing the enzyme reaction product with caustic soda, the solution heated at 140 ° C. for 15 seconds was spray-dried to prepare soy protein.

[Comparative Example 1] Hydrochloric acid was added to an aqueous suspension prepared by hydrolyzing an acid precipitation curd prepared in the same manner as in Example 1 to adjust the pH to 3.5.
, Pepsin (manufactured by Sigma) at 0.05% per dry matter was added, and the enzyme reaction was carried out at 37 ° C for 30 minutes. After neutralizing the enzyme reaction product with caustic soda, the solution heated at 140 ° C. for 15 seconds was spray-dried to prepare soy protein.

Comparative Example 2 An acid-precipitated curd was prepared from defatted soymilk prepared in the same manner as in Example 1 and heated at 90 ° C. for 30 minutes. Hydrochloric acid was added to the aqueous suspension, and the pH was adjusted to 2.5.
And pepsin (manufactured by Sigma) at 0.05% per dry matter was added, and the enzyme reaction was carried out at 37 ° C. for 30 minutes. After neutralizing the enzyme reaction product with caustic soda, the solution heated at 140 ° C. for 15 seconds was spray-dried to prepare soy protein.

Ten micrograms of each of the samples of Examples 2 and 3 and Comparative Examples 1 and 2 were separated by SDS-electrophoresis, and after coomassie blue staining, the density of the band was examined with a densitometer. Glycinin and β- in the control plot of Example 1
Assuming that the conglycinin content was 100%, the reduction rate of each component of each sample was determined. From this result, as in Comparative Examples 1 and 2, p
When H is 2.8 or more, both glycinin and β-conglycinin are hardly decomposed, and those which have been subjected to excessive heat denaturation prior to decomposition will no longer degrade not only glycinin but also β-conglycinin, and selective decomposition products will be obtained. It turns out there is no.

[0029]

[Table 1]

[0030]

According to the present invention, a glycinin-low content soybean protein in which only glycinin is selectively decomposed can be easily obtained, and the use of soybean protein in various food fields such as meat processing, marine processing, and beverages can be expanded. It can greatly contribute to the development of industry.

──────────────────────────────────────────────────続 き Continued on the front page (72) Kumiko Hoshino, Inventor 4-3 Kinudai, Yawahara-mura, Tsukuba-gun, Ibaraki Pref. Tsukuba Research & Development Center, Fuji Oil Co., Ltd. (56) References JP-A-6-261169 (JP, A) JP-A-5-103595 (JP, A) JP-A-2-265441 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A23J 3/16-3/34 JICST file (JOIS )

Claims (4)

(57) [Claims] 1. A method for producing a glycinin-low-content soybean protein-decomposed product obtained by selectively decomposing glycinin in soybean protein by allowing a protease to act on soybean protein at a pH of 1.0 to 2.8 . 2. The method according to claim 1, wherein the protease is allowed to act under conditions in which glycinin is selectively denatured. 3. The method according to claim 2, wherein the selective modification of glycinin is performed by adjusting pH and / or temperature. 4. The process according to claim 1, wherein the degradation rate of glycinin is 60% or more, preferably 80% or more, and the degradation rate of main constituent proteins other than glycinin is 40% or less, preferably 20% or less.