JPH08173052A - Production of soybean protein - Google Patents

Abstract

PURPOSE: To produce soybean protein containing slight phytic acid and its salt capable of sufficiently removing phytic acid and its salt even extracting soybean protein from a raw material containing soybean protein, and readily performing desalting treatment in a short time, and economically advantageous by using an inorganic salt solution of relatively low concentration. CONSTITUTION: An inorganic salt solution having 1.0wt.% <= a concentration < 7.5wt.% is added to a raw material containing soybean protein to extract soybean protein. The extract is subjected to desalting treatment by an electrodialysis or an ultrafiltration, and precipitating at an isoelectric point to remove phytic acid and its salt. As the inorganic salt solution, a solution of alkali metal salt such as table salt, potassium chloride or sodium sulfate is preferably used.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is to extract soybean protein from a soybean protein-containing raw material using a relatively low concentration inorganic salt solution, and efficiently remove phytic acid and its salt from this extract. , A method for producing soybean protein having a low content of phytic acid and salts thereof.

[0002]

2. Description of the Related Art At present, the nutritional intake of Japanese people is good,
It is said that there is almost no nutritional deficiency. However, according to the national nutrition survey conducted every year, the required intake of calcium alone is not satisfied. In order to make up for this shortage of calcium intake, intake of calcium supplement foods such as dairy products, small fish, and seaweed is encouraged.On the other hand, various calcium agents and calcium-enriched foods are being actively developed. There is.

However, since many minerals such as calcium are generally poorly absorbable, a sufficient mineral supplement effect cannot be obtained by simply strengthening the minerals in food. Also, foods that are enriched with only one type of mineral will competitively inhibit the absorption of other minerals,
On the contrary, it has been pointed out that it may cause a deficiency of trace minerals (Dairy Council Digest, Vol.60.
(3)).

Therefore, in recent years, various absorption promoters have been developed which promote absorption of minerals, especially calcium, which are apt to be insufficiently taken. For example, casein phosphopeptide (CPP), which is a peptide having about 20 amino acids containing phosphoserine, is known to suppress insolubilization of calcium in the digestive tract and promote absorption of calcium.

However, since CPP is contained in casein in an amount of about 1/50, there is a problem that it is very expensive. CPP has 20 amino acids.
Since it is a peptide of a certain degree, when it is digested with a proteolytic enzyme contained in gastric juice or intestinal juice, the molecular structure necessary for solubilization of calcium may be destroyed and the desired effect may not be obtained.

On the other hand, soybean protein is mainly used for 11s and 7s.
s, 2.8 s and other globulin proteins, β
-Unlike casein, it contains almost no phosphoserine with a phosphate group. Further, soybean protein contains a considerable amount of phytic acid and its salts, and it is known that such phytic acid and its salts inhibit the body's absorption of minerals, especially calcium (Hayakawa Toshio, No. 1). (A separate volume of the Niigata Food Biotechnology Roundtable Meeting). For these reasons, soybean protein has not been known to have a mineral absorption promoting effect until now (Journal of Japan Society for Nutrition and Food Science, 45 (4)).
333 (1992)).

Further, from soy protein-containing raw materials, for example, 8.
It was reported that phytic acid and its salts could be removed up to 0.14% by extracting soybean protein with 5% saline and treating this extract with an ultrafiltration membrane (Rham. and Jost, J. Food Sci. 44 (2) 596 (197
9)).

In response to the above findings, the present inventors have combined the precipitation method with calcium salt and / or magnesium salt and the electrodialysis method in the process of studying phytic acid and its salt contained in soybean protein. It was found that phytic acid and its salts can be efficiently removed from a soy protein-containing raw material, and that the soy protein with a low content of phytic acid and its salts thus obtained has an excellent mineral absorption promoting effect. We have already applied for Japanese Patent Application No. 6-40558 and Japanese Patent Application No. 6-40559.

[0009]

However, when a soybean protein having a low content of phytic acid and its salt is to be obtained from a soybean protein-containing raw material, for example, the above-mentioned Rham is used.
As stated in the report by Jost and Jost, phytic acid and its salts are removed when the salt concentration is 8.5%, but not enough when it is 7%. It was said that it was difficult to remove phytic acid and its salts when the value was low. However, when extraction is performed with a high-concentration salt solution, there are problems that the desalting process takes time, the productivity is poor, and the manufacturing cost is high.

The present invention has been made in view of the above problems, and an object thereof is to extract phytic acid and soybean protein even if soybean protein is extracted from a soybean protein-containing raw material using a relatively low concentration inorganic salt solution. (EN) Provided is a method for producing soybean protein having a low content of phytic acid and its salt, which is capable of sufficiently removing salt, and therefore can be easily and quickly desalted, and which is economically advantageous. Especially.

[0011]

[Means for Solving the Problems] In the process of studying phytic acid and its salts contained in soybean protein, the present inventors combined desalting treatment by electrodialysis or ultrafiltration with isoelectric focusing. Thereby, even if soybean protein is extracted from the soybean protein-containing raw material with a low-concentration inorganic salt solution,
It was found that phytic acid and its salts can be efficiently removed, and the present invention has been completed.

That is, the method for producing soybean protein of the present invention comprises a step of adding soybean protein-containing raw material with an inorganic salt solution having a concentration of 1.0% by weight or more and less than 7.5% by weight to extract soybean protein, and a step of extracting the soybean protein. Is subjected to desalting treatment by electrodialysis or ultrafiltration, and then phytic acid and its salt are removed by isoelectric precipitation.

The present invention will be described in detail below with reference to preferred embodiments.

First, the step of extracting soybean protein will be described. The kind of raw material containing soybean protein is not particularly limited, and defatted soybean powder, concentrated soybean protein, separated soybean protein,
Various things such as soy milk can be used. These ingredients are
Various commercially available products may be used or may be prepared from raw soybeans. From the viewpoint of increasing the protein extraction rate, the above-mentioned raw materials are preferably those with little denaturation, and specifically, those with a denaturation rate (NSI) of 80% or more are preferable.

The inorganic salt solution added to the above raw material has a concentration of 1.
Use 0% or more and less than 7.5% by weight. If the concentration of the inorganic salt solution is less than 1.0% by weight, even if the desalting treatment by electrodialysis or ultrafiltration is combined with the isoelectric precipitation,
Phytic acid and its salts cannot be efficiently removed. If the amount is 7.5% by weight or more, desalting treatment takes time, which is economically disadvantageous.

As the inorganic salt solution, it is preferable to use an aqueous solution of an alkali metal salt selected from sodium chloride, potassium chloride, sodium sulfate and the like.

The amount of the inorganic salt solution used for extraction is not particularly limited, but considering the yield and the production cost, it is preferably 5 to 20 times the volume of the soybean protein-containing raw material. The extraction temperature and the extraction time are also not particularly limited, but at room temperature,
It is preferable to extract for about 0.5 to 1 hour. PH during extraction
Is preferably in the range of 6-9. When the pH is lower than 6, the soybean protein is difficult to dissolve, and when the pH is higher than 9, there is a problem that the protein is partially decomposed into amino acids, which is not preferable. In addition, the solid-liquid separation method of the extraction liquid after extraction is not particularly limited, such as decantation, centrifugation and filtration.

Next, the extract is desalted by electrodialysis or ultrafiltration. The electrodialysis is preferably performed using an electrodialysis device that uses a separation membrane such as an ion exchange membrane or a molecular sieve membrane.

FIG. 1 shows an example of such an electrodialysis device. That is, between the anode 1 and the cathode 3,
A large number of anion-exchange membranes 5 and cation-exchange membranes 6 are alternately arranged, and when the anion-exchange membrane 5 and the cation-exchange membrane 6 are arranged in this order from the anode 1 side, the liquid to be treated is Flowing desalination chamber 7, cation exchange membrane 6, anion exchange membrane 5
The space between the films arranged in this order is an ion recovery chamber 8 in which cations and anions in the liquid to be treated are collected.

In the anode chamber 2 and the cathode chamber 4, the electrode liquid flow path 1 is provided.
The electrode liquid is circulated by the pump 11 through 0, and the liquid to be treated, that is, the extraction liquid is circulated in the desalination chamber 7 by the pump 13 through the liquid passage 12 for the liquid to be treated. Further, a recovery liquid is circulated in the ion recovery chamber 8 by a pump 15 through a recovery liquid flow path 14.

When a voltage is applied between the anode 1 and the cathode 3, the cations in the extract are collected in the recovery chamber 8 through the cation exchange membrane 6, and the anions in the extract are the anions. It is collected in the collection chamber 8 through the exchange membrane 5. The soybean protein itself is also ionized, but because of its large molecular weight, it cannot pass through the ion exchange membrane and remains in the desalting chamber 7. In this way, the inorganic salt in the extract, phytic acid and its salt, etc. are removed, and the desalted extract can be obtained from the desalting chamber 7 side.

In the above, the ion exchange membranes 5 and 6 have a molecular weight cut-off of preferably 5,000 or less, more preferably 5,000 or less, more preferably, to prevent the permeation of soybean protein itself and selectively permeate phytic acid and salts thereof. 300-1000 ion exchange membranes or molecular sieve membranes are used. As such an ion exchange membrane or molecular sieve membrane, for example, "AC-230-800" (cartridge name, manufactured by Asahi Kasei Corporation) can be used. Membranes having a molecular weight cut off of less than 300 are not preferable because phytic acid and its salts cannot permeate.

As the ion recovery liquid, various inorganic salt solutions and the like can be used. Among them, a salt solution is preferably used, and the concentration thereof is preferably about 0.1 to 1.0% by weight.

On the other hand, ultrafiltration is carried out using an ultrafiltration membrane having a molecular weight cut off of preferably 1000 to 20000, more preferably 1000 to 5000.

The time for the desalting treatment by electrodialysis or ultrafiltration is appropriately determined according to the kind of raw material, the amount and concentration of the extract, and the concentration of the inorganic salt in the extract is about 0.25.
It is preferable to carry out until about 1.5% by weight. If the inorganic salt concentration is higher than 1.5% by weight, purification may be insufficient, and if the inorganic salt concentration is less than 0.25% by weight, soybean protein may aggregate due to desalting, which is not preferable.

Next, the extract desalted as described above is subjected to isoelectric point precipitation to precipitate soybean protein, and solid-liquid separation is performed to remove phytic acid and its salt. Isoelectric point precipitation can be performed by adding a hydrochloric acid solution or the like to the desalted extract to adjust the pH to about 4.5 to 5.5.

The soybean protein separated in this way can be dissolved in water or the like so as to have an appropriate concentration and directly made into a product. However, after being dissolved in water or the like, it is further dried and powdered to be made into a product. It is preferable in terms of product stability. As a drying method, various methods such as a spray drying method and a freeze drying method can be adopted. In any of the above methods, it is preferable that the trypsin inhibitor, which is a problem in digestion of soybean protein, be inactivated by heat treatment at 102 to 120 ° C. for about 5 to 15 minutes.

The soybean protein thus obtained is a high protein and has a mineral absorption promoting effect. As described above, Japanese Patent Application No. 6-40558 and Japanese Patent Application No. 6-40559, which have been filed by the inventors of the present invention, show the effect of soybean protein from which phytic acid and its salts have been removed, to promote mineral absorption. Stated.

Therefore, the soybean protein obtained by the production method of the present invention may be ingested as it is, and
As a material having a mineral absorption promoting effect, dairy products such as milk powder, soy milk, can also be used in place of various vegetable proteins, for example, vegetable protein milk drink, lactic acid beverage, instant soup, various drinks such as soy milk and the like. ,chocolate,
It can be used by adding it to various confectioneries such as cakes and caramels, processed foods such as bread, tofu, ham, sausages and hamburgers, and various foods such as fish paste products such as chikuwa and kamaboko. There is no limitation on the method of addition to the food, and any method such as an aqueous solution addition method or a powder addition method may be used.

[0030]

According to the present invention, when soybean protein is extracted from a soybean protein-containing raw material, by using an inorganic salt solution having a concentration of 1.0% by weight or more and less than 7.5% by weight, phytic acid and its A part of the salt can be insolubilized and precipitated, and the extract is subjected to solid-liquid separation by an ordinary means, whereby phytic acid and a part of the salt can be easily removed.

After the above step, the extract is desalted by electrodialysis or ultrafiltration to more efficiently remove the inorganic salts and the components such as phytic acid and its salts remaining in the extract. Can be removed. In addition,
In the present invention, the concentration of the inorganic salt solution used for extraction is
Since the concentration is 1.0% or more and less than 7.5% by weight, the desalting treatment can be performed in a short time, which is economically advantageous.

When the desalted extract is subjected to isoelectric point precipitation, soybean protein is selectively precipitated. By solid-liquid separating the soybean protein, the remaining phytic acid and its salt are further thoroughly exhausted. It is possible to obtain soybean protein which has a very low content of phytic acid and its salts.

The soybean protein thus obtained, which has a low content of phytic acid and its salts, has a more excellent mineral absorption promoting effect than casein.

According to the method of the present invention, phytic acid and its salts are removed without affecting the amino acid composition of soybean protein itself and the contents of various useful components such as isoflavones originally contained in soybean. can do.

It has been reported that isoflavones contained in soybean, especially daidzein, genistein, daidiin, and genistin, have the same physiologically active effect as estrogen, which is a female hormone (Cheng et al., Science 11
8 164 (1953); Brigger et al., Biochem. J. 58 278.
(1954)), for example, is said to have an effect of suppressing elution of bone mineral.

Therefore, the product obtained by the production method of the present invention can be expected to have not only a mineral absorption promoting effect, but also various physiologically active effects such as the estrogenic effect inherent in soybean.

[0037]

【Example】

Example 1 8 kg of commercially available defatted soybean flakes (trade name "Fuji Takamame", manufactured by Fuji Oil Co., Ltd., modification rate NSI 80 or more) was added to a 4 wt% salt solution (76.8 kg of ion-exchanged water and 3.2 kg of purified salt). 2N-sodium hydroxide solution was added dropwise with gentle stirring to adjust the pH to 8.0, and stirring was continued for 30 minutes and 1 hour, and then pH was adjusted to 8. 0
And soybean protein was extracted. The extract is applied to a basket-type continuous centrifuge (made by Domestic Centrifuge Co., Ltd.) to remove large insoluble residues such as okara, and then a batch type centrifuge (trade name "J6-HC", manufactured by BECKMAN). )Using,
The remaining insoluble matter was completely removed by centrifugation at 4000 rpm for 30 minutes.

The soybean protein extract thus obtained was applied to a commercially available electrodialyzer (trade name: "Micro Acylyzer G").
4DX ", manufactured by Asahi Kasei Co., Ltd.) for 2-3 hours, that is, immediately before the soybean protein is desalted and aggregated at a salt concentration of about 0.2 to 0.3% by weight, phytic acid and its salt. Was removed. As the membrane cartridge of the electrodialysis device, "AC-230-800" (cartridge name, manufactured by Asahi Kasei Co., Ltd.), which is an ion-exchange membrane with a molecular weight cut off of 1000, was used. Saline was used.

Water was added to the desalted extract to dilute it to 3 times its volume, and 1N-hydrochloric acid was added little by little while stirring slowly so as not to cause foaming, to adjust the pH to 5.5.
After allowing to stand for 30 minutes to precipitate the soybean protein at an isoelectric point, decant it to remove the supernatant, and then centrifuge at 4000 rpm for 10 minutes with the above batch type centrifuge to obtain the resulting precipitate. 10 times amount of water was added to the product to well suspend it, and the mixture was vigorously stirred with a homomixer to form a uniform dispersion liquid. 2N-sodium hydroxide or potassium hydroxide was added to this to adjust the pH to 6.8, A soybean protein-containing solution from which phytic acid and its salt were substantially removed was obtained.

When this soybean protein-containing solution was analyzed and measured, phytic acid and its salt were not detected.

Example 2 The 4 wt% saline solution used for extraction in Example 1 was replaced with
Change to a 4.4 wt% potassium chloride solution (43 kg of ion-exchanged water with 2.0 kg of potassium chloride) and adjust the pH of the extract.
The 2N-sodium hydroxide solution used to adjust the pH to 8.0 was changed to a 2N-potassium hydroxide solution, and the same procedure as in Example 1 was followed except that phytic acid and its salts were substantially removed. Got

When this soybean protein-containing solution was analyzed and measured, phytic acid and its salt were not detected.

Example 3 In Example 2, the 4.4 wt% potassium chloride solution used for extraction (2.0 kg of potassium chloride dissolved in 43 kg of ion-exchanged water) was added to a 4.4 wt% sodium sulfate solution (43 kg of ion-exchanged water). Sodium sulfate-containing solution was replaced with 2.0 kg of sodium sulfate) to obtain a soybean protein-containing solution in which phytic acid and its salt were substantially removed in the same manner as in Example 2.

When the soybean protein-containing solution was analyzed and measured, phytic acid and its salt were not detected.

Example 4 2 kg of each soybean protein-containing solution obtained in Examples 1 to 3
And a standing pouch of 3 kg capacity (membrane composition:
12μPET / 25μNY / 9μAl / 100μCPP), high pressure cooking sterilizer (trade name “PCS-40”, manufactured by HISAKA CORPORATION)
After heating at 102 ° C. for 15 minutes to inactivate the trypsin inhibitor, the jelly-shaped soybean protein was spread on a tray and freeze-dried to obtain powdery soybean protein.

Example 5 Water was added to each of the soybean protein-containing solutions obtained in Examples 1 to 3 to dilute it by a double amount, and then powdery soybean proteins were obtained by a spray drying method.

Test Example 1 The soybean protein-containing solution obtained in Example 1 was powdered by the method of Example 4 (hereinafter referred to as "invention product") and commercially available separation as a comparison. The chemical composition with soybean protein (trade name "New Fuji Pro-R", manufactured by Fuji Oil Co., Ltd., hereinafter referred to as "commercial product") and the phytic acid content were measured.

The results are shown in Table 1. The chemical composition was measured by a conventional method, and the phytic acid content was determined by the method of MOHAMED et al. (A.MOHAMED et al., Cereal Chemistry 63, 475, 198).
6) was measured.

[0049]

[Table 1]

As is clear from Table 1, the content of phytic acid and its salt in soybean protein was determined by the method of the present invention.
It was possible to reduce the content to a content that was not substantially contained.

Test Example 2 The amino acid composition in the protein was analyzed and compared for the product of the present invention and the commercial product similar to those used in Test Example 1. The results are shown in Table 2. The analysis of amino acid composition was performed by the method described in “Revised Japanese Food Amino Acid Composition Table” (Edited by Science and Technology Agency, Resource Research Committee).

[0052]

[Table 2]

As shown in Table 2, the soybean protein obtained by the method of the present invention has almost the same amino acid composition as that of the commercially available soybean protein as a raw material. It was revealed that it had almost no effect on the amino acid composition in the protein.

Test Example 3 Commercially available defatted soybean flakes (trade name "Fuji Takamame", manufactured by Fuji Oil Co., Ltd., modification rate NSI 80 or more), 150 g, 0, 1,
Suspended in 1350 ml of an alkali metal salt (sodium chloride, potassium chloride, sodium sulfate) solution having various concentrations of 2, 3, 4, 7, and 10% by weight, and dropwise adding 1N-sodium hydroxide solution while slowly stirring. The pH was adjusted to 8.0 and the stirring was continued, and after 30 minutes and 1 hour, the pH was adjusted to 8.0 again with a 1N sodium hydroxide solution to extract soybean protein. The extract is filtered through a nylon mesh for tofu production to remove large insoluble residues such as okara, and the filtrate is
The precipitate was removed by centrifugation at 5,000 g for 30 minutes to obtain 1100 ml of a soybean protein extract as a supernatant.

10 of the soybean protein extract thus obtained
00 ml was desalted using a commercially available electrodialyzer (trade name "Micro Acylyzer G3", manufactured by Asahi Kasei Corporation, AC-230-800) until the salt concentration became 0.2 to 0.3% by weight.
900 to 950 ml of desalted soybean protein extract was obtained.

To the extract after desalting, 2 volumes of water was added to dilute it to 3 volumes, and 1N-hydrochloric acid was added dropwise little by little while stirring slowly so as not to cause foaming to bring the pH to 5.5. The soybean protein is adjusted and allowed to stand for 30 minutes to precipitate the soybean protein by isoelectric focusing, followed by decantation to remove the supernatant, and then 50
Centrifuge at 00g for 10 minutes, add 9 volumes of water to the resulting precipitate to make a 10-fold dilution, stir strongly with a homogenizer to obtain a uniform dispersion, and adjust to pH 6.6-6.8. A soy protein solution was obtained.

Flow charts of the above operations are shown in FIGS. The * at the bottom of Figure 2 follows the * at the top of Figure 3.

The above operations were carried out using various concentrations of salt solutions as the alkali metal salt solution, soybean protein extract (□ 1), desalted soybean protein extract (◇ 2), pH 6 in FIGS. For protein solutions (△ 3) of .6 to 6.8, measure the amount of protein (mg) and the amount of phytic acid (mg) in 1 ml of each solution, and obtain the ratio (%) of the amount of phytic acid to the amount of protein. It was The amount of phytic acid is MOHAMED
The amount of protein was measured by the Kjeldahl method (Keltech, Inc., automatic nitrogen analyzer).

The results are shown in FIG. In FIG. 4, □ − □ is soybean protein extract (□ 1), and ◇ − ◇ is
Desalted soybean protein extract (◇ 2), △-△ is pH 6.
The ratio (%) of the amount of phytic acid to the amount of protein in each 1 ml of the protein solution (Δ3) of 6 to 6.8 was represented, and +-+ represents the protein content in the soybean protein extract (□ 1).

From the results shown in FIG. 4, the higher the salt concentration, the smaller the proportion of phytic acid relative to the protein amount in the soybean protein extract (□ 1). It can be seen that the amount of phytic acid can be made almost undetectable by performing electrodialysis and isoelectric point precipitation even if extraction is performed with.

As the alkali metal salt solution, potassium chloride solution or sodium sulfate solution having various concentrations is used.
Soybean protein was extracted in the same manner as above, and the amount of protein (mg) in 1 ml of the soybean protein extract (□ 1) and the amount of phytic acid (mg) were measured, and the ratio of the amount of phytic acid to the amount of protein ( %).

As a result, the one using the potassium chloride solution is shown in FIG. 5, and the one using the sodium sulfate solution is shown in FIG. In FIGS. 5 and 6, □ − □ represents the ratio (%) of the amount of phytic acid to the amount of protein, and ++ represents the protein content ratio in the soybean protein extract (□ 1).

From the results of FIGS. 5 and 6, potassium chloride solution,
With any of the sodium sulfate solutions, the higher the salt concentration, the smaller the proportion of phytic acid relative to the protein amount in the soybean protein extract (□ 1).
It can be seen that the amount of phytic acid can be considerably reduced even if extraction is performed with a low-concentration salt solution of not more than wt%.

Example 6 In Example 1, desalting by electrodialysis was changed to ultrafiltration, and “ACP-3053” (trade name, manufactured by Asahi Kasei Co., Ltd.) was used as an ultrafiltration membrane to concentrate and add water. Repeatedly desalting until the same salt concentration as in Example 1 was obtained, and then Example 1
In the same manner as described above, a soybean protein-containing solution from which phytic acid and its salt were substantially removed was obtained.

[0065]

As described above, according to the present invention,
Phytic acid and its salts can be efficiently removed even when soybean protein is extracted from a soybean protein-containing raw material using a low-concentration inorganic salt solution of less than 7.5% by weight. Moreover, since the extraction is performed using a low-concentration inorganic salt solution, desalting treatment can be performed in a short time, which is economically advantageous. Furthermore,
Since phytic acid and its salts can be removed without affecting the amino acid composition and isoflavone content in soy protein, it does not impair the nutritive value and various physiologically active effects of soy protein, and Soy protein with low content can be produced. Since soybean protein from which phytic acid and its salt are removed has a high mineral absorption promoting effect, it is expected to be used as a mineral absorption promoting agent or a food material having a mineral absorption promoting effect.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an example of an electrodialysis device used in the present invention.

FIG. 2 is a flowchart showing the first half of one example of the method for producing soybean protein of the present invention.

FIG. 3 is a flowchart showing the latter half of the embodiment.

FIG. 4 is a chart showing the protein content of the extract and the ratio of the amount of phytic acid to the amount of protein in each step when a salt solution is used in the method for producing soybean protein of the present invention.

FIG. 5 is a chart showing the ratio of the amount of phytic acid to the amount of protein and the amount of protein in the extract when a potassium chloride solution is used in the method for producing soybean protein of the present invention.

FIG. 6 is a chart showing the ratio of the amount of phytic acid to the amount of protein and the amount of protein in the extract when a sodium sulfate solution is used in the method for producing soybean protein of the present invention.

[Explanation of symbols]

 1 Positive Electrode 2 Positive Electrode Chamber 3 Negative Electrode 4 Negative Electrode Chamber 5 Anion Exchange Membrane 6 Cation Exchange Membrane 7 Desalination Chamber 8 Ion Collection Chamber 10 Electrode Liquid Flow Path 12 Processed Liquid Flow Path 14 Recovered Liquid Flow Path 11, 13, 15 pump

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[Procedure amendment]

[Submission date] January 10, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

First, the step of extracting soybean protein will be described. The kind of raw material containing soybean protein is not particularly limited, and defatted soybean powder, concentrated soybean protein, separated soybean protein,
Various things such as soy milk can be used. These ingredients are
Various commercially available products may be used or may be prepared from raw soybeans. Incidentally, from the viewpoint of increasing the extraction rate of the protein it is preferably a the raw material is less denatured, specifically, NSI
(Soluble nitrogenation rate) It is preferably 80% or more.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

[0037]

Example 1 Commercially available defatted soybean flakes (trade name: "Fuji Takamame", Fuji Oil Co., Ltd., NSI (soluble nitrogenation rate) 80 % or more)
8 kg of 4 wt% salt solution (ion exchanged water 76.8 k
(3 g of purified salt dissolved in g) was added thereto, 2N-sodium hydroxide solution was added dropwise with slow stirring to adjust the pH to 8.0, and the stirring was continued for 30
After 1 minute and 1 hour, the pH was adjusted to 8.0 again to extract soybean protein. The extract is applied to a basket-type continuous centrifuge (made by Domestic Centrifuge Co., Ltd.) to remove large insoluble residues such as okara, and then a batch type centrifuge (trade name “J6-HC”, manufactured by BECKMAN). )Using,
The remaining insoluble matter was completely removed by centrifugation at 4000 rpm for 30 minutes.

Claims (6)

[Claims] 1. A step of extracting a soybean protein by adding an inorganic salt solution having a concentration of 1.0% by weight or more and less than 7.5% by weight to a soybean protein-containing raw material, and desalting the extract by electrodialysis or ultrafiltration. After the treatment, a step of removing phytic acid and its salt by isoelectric precipitation is included, and the method for producing soybean protein is characterized. 2. The method for producing soybean protein according to claim 1, wherein the soybean protein-containing raw material is at least one selected from defatted soybean powder, concentrated soybean protein, isolated soybean protein and soybean milk. 3. The method for producing soybean protein according to claim 1, wherein the inorganic salt solution is an aqueous solution of an alkali metal salt selected from common salt, potassium chloride and sodium sulfate. 4. The method for producing soybean protein according to claim 1, wherein the extraction is performed under conditions of pH 6-9. 5. The electrodialysis is performed using an ion exchange membrane or a molecular sieve membrane having a molecular weight cut off of 5000 or less.
The method for producing soybean protein according to any one of 1. 6. The ultrafiltration, wherein the molecular weight cutoff is from 1000 to 20.
The method for producing soybean protein according to any one of claims 1 to 4, which is carried out using 000 ultrafiltration membranes.