JPH0892123A - Low phosphorus content soybean protein enzymatic degradation product for renal disease - Google Patents

Abstract

(57) [Summary] [Purpose] The objective was to provide a soybean protein enzymatic hydrolyzate useful for renal diseases, which has an extremely low total phosphorus content and an extremely low phytin-state phosphorus content. [Composition] A soybean protein enzymatic hydrolyzate for renal diseases having a total phosphorus content of 0.1% or less and a phytic acid phosphorus content of 0.004% or less. [Effect] A soybean protein enzymatic degradation product useful for renal diseases was obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a low phosphorus content soybean protein enzymatic degradation product for renal diseases.

[0002]

BACKGROUND OF THE INVENTION Soybean protein is a nutritionally excellent product with a good balance of amino acids, but like other proteins derived from seeds, the phytic acid-, phospholipid-, and inorganic salt-containing phosphorus contents exist. , Which reduces the nutritional value.

Phytic acid reacts with mainly divalent metal ions such as calcium ions, magnesium ions, iron ions and zinc ions to form a precipitate, which adversely affects the absorption of minerals required by the human body in the digestive tract. It is also known that phosphorus itself stimulates parathyroid hormone due to excessive intake, adversely affects bone formation, and causes a decrease in renal function.

Usually, the soybean protein isolate or its decomposition product has a total phosphorus content of about 1% and a phytic acid phosphorus content of about 0.6%. On the other hand, in patients with renal failure, it is necessary to control the phosphorus intake to 600 mg / day or less.
In fact, since phosphorus is ingested through various foods, it is desirable to keep the phosphorus content in each food material as low as possible. In the case of low phosphorus milk, which is a food for specified health uses, the phosphorus content is reduced to 1/5 of milk (0.08% / milk).

On the other hand, methods for removing phytic acid from soybean protein have been extensively studied so far, for example, (a) pH 1
Method of precipitating and removing only phytic acid in one or more highly alkaline regions, (b) Method of separating and removing using UF membrane or ion exchange resin, (c) Salt concentration of 8.5% under neutral or weak alkaline There are a method of removing the precipitate by the above, and a method of decomposing and removing with (5) phytase.

However, the known method for separating phytic acid from a protein is such that the protein becomes insoluble during the treatment,
It was not practical because the flavor was deteriorated and the treatment was expensive.

Further, in JP-A-63-267251, soybeans are immersed in an aqueous solution having a pH of 3.0 to 6.5 from which divalent and polyvalent cations have been removed to reduce phosphorus and potassium in soybeans. Although a method is described, the phosphorus content after treatment is several hundred mg / 100 g, which is not satisfactory.

Further, Japanese Patent Application Laid-Open No. 4-51872 discloses a method in which a substance which dissociates into a divalent metal ion after enzymatically decomposing soybean protein is added and subjected to heat treatment to precipitate and remove phytic acid. It cannot be removed to the low phosphorus levels obtained with the present invention.

[0009]

As described above, it is an object of the present invention to obtain a soybean protein enzymatic degradation product for renal diseases, which has a very low phytic acid content and a very low total phosphorus content.

[0010]

Means for Solving the Problems The present invention has been studied in view of the above problems, and as a result, soybean protein was decomposed with an enzyme to improve fluidity, and then treated with a specific anion exchange resin. As a result, the present inventors have completed the present invention by obtaining the finding that an enzymatic degradation product of soybean protein having a low phytic acid content and an extremely low phosphorus content that is effective for renal diseases can be obtained.

That is, the present invention has a total phosphorus content of 0.1% or less (preferably 0.05% or less, more preferably 0.0% or less).
25% or less), and the phytic acid phosphorus content is 0.00
It is 4% or less (preferably 0.002% or less, more preferably 0.001% or less) soybean protein enzymatic degradation product for renal diseases.

The constituent essential amino acid per 1 g of protein in the enzymatic decomposition product of soybean protein is L-threonine: 30 to 46 m.
g, L-tyrosine: 28-42 mg, L-phenylalanine: 42-62 mg, L-cystine: 10-16 m
g, L-methionine: 10-14 mg, L-valine: 3
7-55 mg, L-isoleucine: 37-55 mg, L
-Leucine: 62-94 mg, L-lysine: 50-
74 mg, L-tryptophan: 11-17 mg, L-
Histidine: It can be in the range of 19 to 29 mg.

The total phosphorus content of the enzymatically decomposed soybean protein for renal diseases of the present invention is suitably 0.1% or less (preferably 0.05% or less, more preferably 0.025%). Excessive intake of phosphorus causes imbalance in calcium balance and enhanced parathyroid function, which is harmful to health. Particularly in patients with kidney disease, the phosphorus content in blood is chronically high, and the harmful effects of excessive phosphorus are serious. In patients with renal failure, phosphorus intake needs to be kept below 600 mg / day. In fact, since phosphorus is ingested through various foods, it is desirable to keep the phosphorus content in each food material as low as possible. In the case of low phosphorus milk for kidney disease, which is a food for specified health use, the phosphorus content of 1/5 of milk (0.08
% / Milk).

The enzymatic degradation product of soybean protein for renal diseases of the present invention has a total phosphorus content of 0.1% or less (preferably 0.05%).
It is extremely low (below, more preferably 0.025% or less), and can be effectively and safely used as a protein nutrition source for renal diseases.

The phytic acid phosphorus content of the enzymatic soybean protein hydrolyzate for renal diseases of the present invention is 0.004% or less (preferably 0.002% or less, more preferably 0.001% or less).
% Or less) is suitable. Phytic acid is said to bind to minerals such as calcium and magnesium and inhibit absorption in the body, but as in the present invention, the phytic acid phosphorus content is 0.004% or less (preferably 0.002% or less, If it is a protein degradation product that is extremely low (more preferably 0.001% or less), it is effectively absorbed without inhibiting mineral absorption, and is comprehensively effective for renal diseases.

The low phosphorus-containing soybean protein enzymatic degradation product for renal diseases of the present invention can be obtained, for example, by the following method.

It can be obtained by decomposing a protein with an enzyme in a water system and treating it with an acrylic weakly basic anion exchange resin.

The protein used in the present invention is preferably a vegetable protein, particularly soybean protein, for example, isoelectric precipitation,
A protein recovered by alcohol precipitation, UF membrane separation, etc. can be used.

The enzyme used in the present invention may be any enzyme as long as it can be used for food or pharmaceutical production. Enzymatic degradation is possible at the temperature and pH at which the enzyme acts. The concentration of the protein to be decomposed may be any concentration as long as the enzyme acts, but usually 5% to 1
A range of 5% is preferable.

The insoluble matter generated by the enzymatic decomposition may or may not be removed.

When the insoluble matter is removed, either the batch method or the column method can be applied to the resin treatment described later. However, when the insoluble matter is contained, the batch method or the column method in which the liquid is passed through is preferable. .

What is important in the present invention is (a) removal of phosphorus-containing compounds with a specific anion exchange resin,
(b) To decompose the soybean protein with an enzyme prior to the treatment with a specific anion exchange resin to reduce the viscosity of the soybean protein in the solution state and improve the fluidity without impairing the nutritional value of the soybean protein. To reduce the phosphorus content.

When soybean protein is treated with an ion-exchange resin in an aqueous solution, it is well known that the soybean protein is insoluble due to a polymer and causes clogging, and the viscosity is high, so that it must be made into a very dilute solution. , Causing industrial difficulties.

Acrylic weakly basic anion exchange resin is suitable as the adsorption resin used for removing the phosphorus-containing compound after enzymatic decomposition. Other anion exchange resins cannot reduce the phosphorus content as much as the present invention.

The main phosphorus-containing compounds present in soybean protein are phytic acid, phospholipids and phosphates, all of which can be adsorbed and removed by an acrylic anion exchange resin.

When the acrylic anion exchange resin is used, it is essential that the functional groups of the resin are positively charged. Therefore, it is appropriate that the pH is 9 or less, preferably 7 or less. In this case, either the batch method or the column method can be used.

The above-obtained enzyme-decomposed liquid treated with the acrylic anion exchange resin has a total phosphorus content of 0.1% or less (preferably 0.05% or less, more preferably 0.025) in terms of solid content. %) And the phytic acid-phosphorus content is 0.004% or less (preferably 0.002% or less, more preferably 0.001% or less), which adversely affects the absorption of minerals required by the human body. It is extremely useful as a protein source for patients with renal disease without affecting. Usually, it can be used as a raw material for foods, pharmaceuticals, etc. for renal diseases in the solution state after sterilization, and it is concentrated in the form of a concentrated solution according to a conventional method or spray-dried to obtain a powder form. It can be used as a raw material for foods, pharmaceuticals, etc. for renal diseases.

[0028]

EXAMPLES The following examples are given to further clarify the features of the present invention. Example 1 Isolated soy protein (“New Fuji Pro-” manufactured by the applicant company)
R ") 100 parts by weight is dissolved in 900 parts of water, 2 parts of proteolytic enzyme (" Protin "manufactured by Daiwa Kasei Co., Ltd.) is added thereto, and the mixture is incubated at 50 ° C for 5 hours and then centrifuged (5000 rpm x 30 minutes). The insoluble matter was removed by heating at 80 ° C. for 30 minutes to inactivate and sterilize the enzyme, and freeze-dried to obtain an enzymatic decomposition product (SH).

Acrylic weakly basic anion exchange resin ("KA890" manufactured by Sumitomo Chemical Co., Ltd.) having a diameter of 1.4c
m column up to a height of 15 cm (resin volume 23 cm
2) Then, 50 ml of 5% caustic soda solution and 500 ml of ion-exchanged water were passed through to wash.

On the other hand, the above-mentioned enzymatic decomposition product (SH) was dissolved in ion-exchanged water, the pH was adjusted to 4.5 with 10% hydrochloric acid, and the final protein concentration was adjusted to 10% with ion-exchanged water. It was adjusted.

The above-prepared solution was passed through the top of the column that had been packed and washed with KA890 at a rate of 51 ml / h, and the treated solution eluted from the bottom of the column was collected and the method of Mohammed et al. (Cereal Chem. 63. 475.1986), the phytic acid content was sequentially measured. The result is shown in FIG.

As shown in FIG. 1, the enzyme decomposition solution is passed through,
If the amount exceeds 1219 ml (121.9 g of protein, 5.3 g per 1 ml of resin), the phytic acid in the enzyme-decomposed solution is not completely adsorbed on the resin and leaks.

The eluate from which phytic acid had been completely adsorbed and removed by the resin was collected and freeze-dried to obtain an enzymatic degradation product (SHR) having a low phosphorus content. Table 1 shows the analysis results of SH and SHR.

[0034]

[Table 1]

---------------------------------------------------- ---------------- SH SHR -------------------------------- ------------------------------- Total phosphorus content (mg / 100g protein) 840 24 Phytic acid phosphorus content (same as above) 710 0 Phospholipid Phosphorus content (same as above) 0 0 -------------------------------------- ------------------------- (Amino acid composition (mg / g protein) L-threonine 37 37 L-tyrosine 34 34 L-phenylalanine 49 49 L -Cystine 13 13 L-methionine 12 12 L-valine 44 44 L-isoleucine 44 44 L-leucine 71 71 L-lysine 63 63 L-tryptophan 12 12 L-histidine 23 23 L-aspartic acid 119 119 L-serine 52 52 L-glutamic acid 207 207 L-proline 53 53 gly Syn 40 40 L-alanine 38 38 L-arginine 77 77 ------------------------------------- -------------------------- As shown in Table 1, by treating the enzymatic decomposition product of soybean protein with anion exchange resin, the phosphorus content was increased. Comparative Example 1 The enzymatic degradation product (SH) prepared in Example 1 was used in a protein amount of 10
0 part was dissolved in ion-exchanged water, the pH was adjusted to 7.0 with 10% sodium hydroxide solution, and the final protein concentration was adjusted to 10% with ion-exchanged water.

To the above prepared solution, 3 parts or 6 parts of calcium chloride is added and dissolved. Next, in a hot water bath, add this liquid to 70 ° C.
After heating for 30 minutes, cool under running water. The resulting precipitate was removed by centrifugation (5000 rpm × 30 minutes), and the supernatant was freeze-dried (SHC). Table 2 shows the analysis results in comparison with SHR.

[0037]

[Table 2] ---------------------------------------------- --------------------- SHR SHC CaCl2 3 parts CaCl2 6 parts --------------------- ---------------------------------------------- Total phosphorus content ( mg / 100g protein) 24 210 170 Phytic acid phosphorus content (same as above) 0 0 0 Phospholipid phosphorus content (same as above) 0 0 0 -------------------- ----------------------------------------------- In Table 2 As shown, in the method of adding a divalent metal ion and insolubilizing it by binding with phytic acid to remove a precipitate,
Although phytic acid phosphorus can be excluded, the total phosphorus content cannot reach the low levels obtained with the present invention. Comparative Example 2 The enzymatic degradation product (SH) prepared in Example 1 was dissolved in ion-exchanged water, the pH was adjusted to 4.5 with 10% hydrochloric acid, and ion-exchanged so that the final protein concentration was 10%. It was adjusted with water.

A column was filled with a polysulfone-based weakly basic anion exchange resin (“WA20” manufactured by Mitsubishi Kasei Co., Ltd.) and washed in the same manner as in Example 1.

The enzyme-decomposed solution prepared above was passed through the same column under the same conditions as in Example 1, the eluate was fractionated, and the phytic acid content was measured.

When WA20 was used, phytic acid leaked from the initial liquid eluted from the column without being adsorbed and removed, and was unsuitable for this purpose.

[0041]

[Effect] According to the present invention, a soybean protein enzymatic degradation product useful for renal diseases is obtained because the total phosphorus content is extremely low and the phytin-state phosphorus content is also extremely low.

[Brief description of drawings]

 "

1] is a drawing showing the treatment amount of the enzymatic decomposition product in the treatment of anion exchange resin obtained in Example 1 and the degree of adsorption on the exchange resin.

Claims (2)

[Claims] 1. A soybean protein enzymatic hydrolyzate for renal diseases having a total phosphorus content of 0.1% or less and a phytic acid phosphorus content of 0.004% or less. 2. A constituent essential amino acid per 1 g of protein in the enzymatic degradation product of soybean protein is L-threonine: 30 to 46.
mg, L-tyrosine: 28-42 mg, L-phenylalanine: 42-62 mg, L-cystine: 10-16
mg, L-methionine: 10-14 mg, L-valine:
37-55 mg, L-isoleucine: 37-55 mg,
L-leucine: 62-94 mg, L-lysine: 50
~ 74 mg, L-tryptophan: 11-17 mg, L
-Histidine: The soybean protein enzymatic degradation product for renal disease according to claim 1, which is in the range of 19 to 29 mg.