WO2004104036A1

WO2004104036A1 - Process for producing soyeban whey protein and digested soybean whey protein

Info

Publication number: WO2004104036A1
Application number: PCT/JP2004/006531
Authority: WO
Inventors: Masahiko Samoto; Wataru Kugimiya
Original assignee: Fuji Oil Company, Limited
Priority date: 2003-05-21
Filing date: 2004-05-14
Publication date: 2004-12-02
Also published as: JPWO2004104036A1

Abstract

It is intended to provide a process for efficiently collecting and producing protein contained in soybean whey at a high purity. In the course of collecting separated soybean protein from soybean milk or defatted soybean milk by isoelectric precipitation, protein contained as the by-product in soybean whey can be hardly collected at a high efficiency by the existing methods. Even though such protein can be collected, the obtained product suffers from some problems such as having a low protein purity. This problem can be solved by providing a process which comprises heating soybean whey in the coexistence of Ca ion, collecting the thus formed precipitate, then washing the precipitate under acidic conditions and neutralizing to thereby efficiently obtain highly pure soybean protein.

Description

Specification

Production method of soy whey protein and soy whey protein hydrolyzate

Technical field

The present invention relates to a method for producing a soybean whey protein and a soybean whey protein hydrolyzate that can be efficiently and highly recovered from soybean whey.

Background art

[0002] 7S globulin (also referred to as -conglycinin) and 11S globulin (also referred to as dalycinin), which are the main storage proteins of soybeans, are separated from soymilk or defatted soymilk by isoelectric precipitation or heating. The soybean whey produced as a by-product at that time contains lectin (also called hemagglutinin), which is a trace protein of soybean, and a nick-type trypsin inhibitor. It has been reported that these soy whey proteins have various physiological activities and are expected as a new healthy nutritional material.

[0003] However, since these are trace components, it is essential to efficiently recover them with high purity in order to use them as protein materials. Conventionally, there have been several reports of the removal of aggregates (including soy whey protein) formed when soybean whey is heated in the presence of calcium ions and the recovery of soybean oligosaccharides in the supernatant. Le, ru (Patent Documents 1 and 2).

[0004] These reports aim at the recovery of soybean oligosaccharides and do not extend to the idea of how to purify soybean whey protein, a by-product thereof, and use it effectively. . Therefore, even if the heat aggregates of soy whey are recovered by the methods shown in Patent Documents 1 and 2, there is a problem that the protein purity is extremely low. In addition, the use of calcium ions increases the ash content, and the salty taste is strongly felt.

Patent Document 1: JP-A-3-22971

Patent Document 2: JP-A-59-179064

Disclosure of the invention

Problems the invention is trying to solve

[0006] Therefore, the present invention provides a soybean whey protein (Lecty) which is a trace protein of soybean from soybean whey. It is an object of the present invention to provide a method for producing soybean soy protein which can efficiently and highly recover tryptic inhibitors (such as lipstick type trypsin inhibitor).

Means for solving the problem

[0007] The inventors of the present invention have conducted intensive studies and found that the purity of soybean whey protein tends to increase by exposing the heated aggregate obtained from soybean whey to acidity and removing soluble matter. Obtained. As a result of further research, the inventors found that by adjusting the pH during washing to a specific pH range, the protein purity of soybean hoprotein was dramatically increased, and completed the present invention. .

[0008] That is, the present invention is a method for producing soybean hoprotein, which comprises exposing heated aggregates produced by heating soybean soybean to an acidity of pH 4 or less to remove soluble matter. In the above-mentioned production method, the temperature at which the soybean honey is heated is preferably 80 to 120 ° C. Heating is preferably performed in the presence of alkaline earth metal ions. The pH when heating soybean ho is preferably 2-9. It is preferable that the obtained soybean hoprotein contains at least 96 mg of protein per lg of solid content (60% by weight or more as a protein when the nitrogen conversion coefficient is 6.25) as nitrogen content by the Kedar method. Further, the present invention is a method for producing solubilized soybean hoprotein, which further comprises neutralizing the soybean soybean protein obtained by the above production method and then heating (100 to 150 ° C). Further, the present invention is a method for producing a soybean protein decomposed product, wherein a protease is allowed to act on the soybean protein obtained by the above production method.

The invention's effect

According to the present invention, soybean hoproteins such as soybean lectin and trypsin inhibitor with high purity can be provided by an industrially feasible production method. The production method capable of efficiently preparing high-purity soybean soybean protein as in the present invention is very promising as a technique for supplying soybean soybean protein as a soybean protein material.

Unlike the main stored soybean protein, the protein contained in soybean ho was contained only in trace amounts and was not easy to recover. By adopting this production method, it is possible to recover this soybean soy protein with high efficiency and high purity, and to impart solubility if desired. Processing and expanding the use of soybean protein that has been used so far This is made possible by adopting this manufacturing method.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] The present invention is a method for producing soy whey protein, which comprises exposing heated aggregates generated by heating soy whey to an acidity of pH 4 or less to remove soluble substances.

[0011] The soybean whey used in the present invention is obtained by removing 7S globulin or 11S globulin, which is a main storage protein of soybean, during or after water extraction from defatted soybean or soybean, and as a protein, lectin or trypsin inhibitor. And trace components such as Preferably, defatted soybeans are extracted with an aqueous solvent to remove soybean milk, soymilk is obtained, and 7S globulin or an isolated soybean protein containing 11S globulin as a main component is recovered by isoelectric precipitation (pH 4.4-4.6).

The soy whey obtained as a by-product is used. Of course, soy whey obtained as a by-product when defatted soy is washed with an acidic aqueous solution or alcohol to obtain concentrated soy protein, or soy whey obtained as a by-product during the manufacturing process of tofu, soy milk, soy sauce, natto, etc. It can be used and is not particularly limited.

[0012] The soybean whey contains about 15 to 30% by weight of crude protein per total solid content, depending on the preparation method. Its composition is different from the main storage protein of soybeans, and it is composed mainly of 10-20% of lectin, 30 and 50% of nick-type trypsin inhibitor in total protein, and other components such as 3/3 amylase and lipoxygenase. . And the composition of j3_conglycinin and glycinin, the main storage proteins of soybean, is less than 10% of the total protein.

[0013] In the present invention, first, a step of heating soybean whey and recovering a substance that aggregates (heated aggregate) is performed. By heating, proteins in the soybean whey undergo thermal denaturation and aggregate. The caloric heat temperature is a temperature sufficient for denaturing the soy whey protein, preferably at 80-120 ° C, more preferably at 85-100 ° C. If the heating temperature is lower than 80 ° C, the growth into agglomerates is insufficient, and if the heating temperature is higher than 120 ° C, coloring such as browning is likely to occur. The heating time depends on the temperature as long as it is sufficient for the formation of agglomeration, but it is sufficient if the heating time is in the range of 5-60 minutes.

When soy whey is heated, coexistence of an alkaline earth metal ion in advance promotes aggregation of the soy whey protein, which is preferable for efficiently collecting the heated aggregate. . The alkaline earth metal ion may be added in an amount of 0.02 to 1% by weight based on the amount of soybean whey. The kind of the alkaline earth metal is not particularly limited as long as it is a salt or hydroxide containing Ca or Mg.

[0015] It is preferable that the pH of soybean whey at the time of heating is 29. If the pH is less than 2, an unfavorable flavor may be caused by an acid, and if the pH exceeds 9, the flavor may be deteriorated by an alkali. More preferably, the pH is suitably set at 47, and even more preferably at 5-6. If the pH is less than 4, a large amount of acid is required for pH adjustment, so that the ash content of the heat-aggregate increases, making it difficult to purify the protein afterwards. On the other hand, if the pH exceeds 7, the heat aggregates tend to be tight and separation is difficult.

Next, the heated aggregate is collected by a separation means such as centrifugation or membrane separation. At this stage, soybean oligosaccharides such as stachyose and raffinose contained in soybean whey are removed, and about 50% of the nitrogen content in soybean whey sediments. Lectins and trypsin inhibitors are recognized as major protein components in this heat aggregate, and other trace protein components such as lipoxygenase ゃ low molecular weight components having a molecular weight of 20,000 or less are also included. However, the purity of the protein in the heat-aggregated product was estimated to be about 80 mg / g (solid content) per lg of solid content (50% by weight of protein when the nitrogen conversion factor was 6.25), according to the measurement of the Kenoledar method. Purity is too low to be treated as a soybean protein material, which is undesirable. In addition, as it is, it contains about 30% ash per solid content and has a strong salty taste.

[0017] The reason why the purity of the protein is so low is that, as described above, the ash such as Ca contains about 30% of the solid content. This ash forms a complex with phytic acid and the like, and this is considered to be coagulated together with soy whey protein by heating. This heated aggregate has low protein purity even after washing with pure water.

[0018] The present invention is characterized in that water is further added to a heated aggregate of soybean whey and exposed to strong acidity to wash out solubilized impurities. Here, exposure under strong acidity means exposure to pH 4 or less, preferably pH 3 or less, and more preferably pH 1.5-2.5. If the pH exceeds 4, impurities other than proteins cannot be sufficiently solubilized. For example, no matter how much water is precipitated by heating at about pH 5.3 and washed with water around pH 5.3 4.5, protein purity does not increase. In other words, even when exposed to slightly acidic and strong alkaline conditions, the protein While there is almost no change in the composition, exposure of the precipitate under strongly acidic conditions makes it possible to solubilize impurities other than proteins as much as possible. The kind of acid used for adjusting the acidity is not particularly limited, and hydrochloric acid or phosphoric acid may be used.

[0019] Since the protein maintains insolubility at this time, by utilizing the dissolution behavior of both, washing and removal of the acid-soluble matter (ash content, which is considered to be mainly phytic acid), removes the protein by heat aggregation. It is possible to dramatically increase the protein purity in a product. When washing, the pH may be higher than that of the above-mentioned exposing step, and the pH may be adjusted to 5 or less, more preferably adjusted to pH 1.54. When the pH exceeds 5, impurities which have been solubilized with an acid are insolubilized again and precipitate, so it is better to avoid them.

[0020] The obtained soybean whey protein has a nitrogen content of 96 mg or more per lg of solid content, preferably

It has a purity of 112 mg or more (when the nitrogen conversion coefficient is 6.25, the protein is 60% by weight or more, preferably 70% by weight or more, more preferably 75% by weight or more). The protein per during soy whey protein, lectin 15- 30 weight ^_0/0, Kuni'tsu type trypsin inhibitor is contained 80 wt% 40-. Separation of the soluble matter from the acid and the insoluble soy whey protein may be performed by using a separation means such as centrifugation or membrane separation.

[0021] The resulting high-purity soybean whey protein was the by the force desired to have become insoluble, this pH 6. 5-9, preferably after Chu禾Ro in pH7- 8, 100- 150 ^o C, preferably Is solubilized by strong heating at 110-120 ^° C, so that it is possible to provide soluble and high-purity soy whey protein. As the heating means, either indirect heating or direct heating can be used, but it is preferable to perform steam-blown direct heating in terms of flavor and coloring.

Further, if desired, the soybean whey protein hydrolyzate can be provided by subjecting the soybean whey protein obtained as described above to a hydrolysis using a protease and removing an insoluble fraction if necessary. The protease to be used is not particularly limited, but it is preferable to use an endo-type protease derived from a microorganism, a plant or an animal in order to obtain a higher physiological activity such as angiotensin converting enzyme inhibitory activity. Specifically, metalloproteases (such as thermolysin), serine proteases (such as trypsin, chymotrypsin, thrombin, plasmin, elastase, and subtilisin), thiol proteases (such as papain, fusin, bromelain, and cathepsin B), and aspartic protease (such as pepsin) Syn, chymosin, cathepsin D, etc.). It is considered that the obtained soybean whey protein hydrolyzate contains various physiologically active peptides such as angiotensin converting enzyme inhibitory peptide and antioxidantly active peptide. Therefore, it is possible to apply this degraded product as it is, or to fractionate a fraction containing a specific bioactive peptide, and apply it as a bioactive peptide-containing composition to health foods such as pharmaceuticals and specified health foods. it can.

[0023] Lectins and trypsin inhibitors contained in soy whey have conventionally been shunned as non-nutritional proteins. However, the soy whey protein or the soy whey protein hydrolyzate obtained by the production method of the present invention sufficiently denatures these proteins and converts them into a hydrolyzate, so that the trypsin inhibitory activity and the like have disappeared. . Furthermore, since the amount of sulfur-containing amino acids such as cysteine and methionine is higher than that of isolated soybean proteins and the like, the amino acid score, which is an index of the amino acid composition balance, is also excellent, which is more nutritionally desirable. Therefore, it can be newly used as a soybean protein material or a peptide-containing composition having excellent nutritional sources and physiological functions. This soybean whey protein and its degraded product also contain abundant branched-chain amino acids such as leucine, isoleucine, and phosphorus, and are more abundant than peptides derived from isolated soybean protein, and thus have an advantage as a supplement for athletes.

Example

Hereinafter, the effects of the present invention will be made clearer by exemplifying examples and comparative examples, but the present invention is not limited to these exemplifications.

[Comparative Example 1]

One part of defatted soybeans was kneaded with 10 times water and stirred well, and hydrochloric acid was added to adjust the pH to 4.5. Insolubles such as 7S globulin and 11S globulin which aggregated by isoelectric precipitation were removed by centrifugation to obtain soy whey. Slaked lime was added to the soybean whey, the pH was adjusted to 5.3, and the mixture was allowed to stand at 90 to 95 ° C for about 15 minutes to collect a coagulated fraction by centrifugation. This was used as a calcium heat-aggregated soybean whey protein. This fraction was freeze-dried and its nitrogen content was determined. Table 1 shows the results.

[Example 1]

For 1 part of the solid content weight of the calcium heat-aggregation type soy whey protein of Comparative Example 1, Adjust the pH to 2.0 by adding 10 volumes of water, adding hydrochloric acid, stirring at 5000 ホモ m for 10 minutes with a homomixer, centrifuging (1000G x 10 minutes), and removing the precipitate. Collected. The recovered precipitate was lyophilized to determine the solids weight recovery and nitrogen content. Table 1 shows the results. The amino acid composition of the recovered product was also examined and compared with that of the isolated soy protein. Table 2 shows the results.

[Comparative Example 2]

For 1 part of the solid content of the calcium-heat-aggregated soybean whey protein of Comparative Example 1, 10 times the amount of water was added, and the homomixer was stirred at 5,000 m for 10 minutes and centrifuged (1000G x 10 minutes). The precipitate was collected. At this time, the pH after water addition was 5.5. The recovered precipitate was lyophilized to determine the solids weight recovery and nitrogen content. Table 1 shows the results.

[Comparative Example 3]

To 1 part of the solid content weight of the calcium-heat-aggregated soy whey protein of Comparative Example 1, water was added 10 times, sodium hydroxide was added, and the pH was adjusted to 10.0. The mixture was stirred and centrifuged (1000 G × 10 minutes), and the precipitate was collected. The recovered precipitate was lyophilized to determine the solids weight recovery and nitrogen content. Table 1 shows the results.

[0029] (Table 1)

* Protein content% when nitrogen conversion coefficient is 6.25

** Recovery% of each solid content when the solid content of the substance recovered in Comparative Example 1 is set to 100

[0030] (Table 2) (Mg of protein lOOmg) Amino acid Soy whey protein Isolate soy protein Arginine 6.0 7.7 Lysine 6.4 6.1 Histidine 2.3 2.7 Phenylalanine 6.0 5.3 Tyrosine 3.7 3.7 Leucine 8.8 7.8 Isoleucine 6.0 4.8 Methionin 1.3 1.2 Valine 5.5 4.8 Garanin 4.4 4.0 Glycine 4.4 4.0 Proline 5.4 5.4 Glutamic acid Glutamine 11.9 19.2 Serine 5.9 5.0 Threonine 4.7 3.5 Aspartic acid Asparagine 13.6 11.5 Tributofan 2.1 1.3 Cysteine 1.7 1.3

[0031] As a result, as shown in Example 1, it can be seen that by removing the fraction solubilized under strong acidity, the protein purity is dramatically improved and the ash content can be reduced as much as possible. Next, the protein of Example 1 in which the protein purity was improved was solubilized.

[Example 2]

Prepare a 5% mixed solution of the one prepared in Example 1, adjust the pH to 7.8 by adding sodium hydroxide, heat at 120 ° C for 15 minutes, centrifuge (1000GX10 minutes), The protein remaining in the supernatant, that is, the nitrogen content of the supernatant relative to the total nitrogen content was determined. The results are shown in Table 3.

[Comparative Example 4]

A 5% mixed solution of the one prepared in Example 1 was prepared, the pH was adjusted to 6.5 by adding sodium hydroxide, heated at 95 ° C for 15 minutes, centrifuged (1000 GX for 10 minutes), The protein remaining in the supernatant, that is, the nitrogen content of the supernatant relative to the total nitrogen content was determined. as a result Are shown in Table 3.

(Table 3) Nitrogen content of sample supernatant Sample 2 75% Comparative 4 12%

[0035] From these results, it was possible to re-solubilize the insoluble soybean whey protein by neutralizing and then heating strongly.

Example 3

A 5% mixed solution of soy whey protein prepared in Example 1 was prepared, pH was adjusted to 7.8 by adding sodium hydroxide, and heating was performed at 120 ° C for 15 minutes. Then, this was adjusted to pH 8 with sodium hydroxide, and 1% of “proteases 3” (manufactured by Daiwa Chemicals, Bacillus subtilis-derived endoprotease) per soybean whey protein was added and reacted at 60 ° C for 4 hours. The mixture was adjusted to pH 4.5 with phosphoric acid, heated at 100 ° C for 20 minutes to stop the reaction, centrifuged (1000G x 5 minutes), the supernatant was collected, and the soy whey protein hydrolyzate was removed. Obtained. When the molecular weight of this degradation product was measured by gel filtration, 70% or more of the peptides had a molecular weight of 1,000 or less.

Claims

The scope of the claims

A method for producing soy whey protein, comprising exposing heated aggregates produced by heating soy whey to an acidity of pH 4 or less to remove soluble substances.

The method according to claim 1, wherein the temperature at which the soy whey is heated is 80 to 120 ° C.

2. The method according to claim 1, wherein the heating is performed in the presence of an alkaline earth metal ion.

2. The method according to claim 1, wherein the pH when heating the soy whey is 2-9.

2. The process according to claim 1, wherein the soybean whey protein contains at least 96 mg of protein per lg of solid content (60% by weight or more assuming a nitrogen conversion factor of 6.25) based on the Kenoledar method.

A method for producing a solubilized soy whey protein, which comprises heating the neutralized soy whey protein obtained by the method according to claim 1, followed by heating (100 to 150 ° C).

A method for producing a soy whey protein hydrolyzate, wherein a protease is allowed to act on soy whey protein obtained by the method according to claim 1.