Separation and extraction method of low-phytic-acid high-emulsibility soybean protein

Abstract

The invention relates to a separation and extraction method of low-phytic-acid high-emulsibility soybean protein, which belongs to the technical field of food processing, and is characterized in that low-temperature defatted soybean meal is crushed, sieved and dried, then water is added to prepare slurry, the slurry is modified by microwaves, the pH value of the slurry is adjusted to be alkaline, and after heating, stirring, extraction and residue filtration, the low-phytic-acid high-emulsibility soybean protein is obtained. Centrifugally separating the filtrate to obtain supernate; adding phytase, stirring for reaction, and carrying out esterification reaction on the phosphoric acid subjected to enzymolysis and protein; the pH value of the solution after enzymolysis is adjusted to be acidic, phosphorylated protein is flocculated, and the phosphorylated soybean protein is prepared through centrifugal separation, curd precipitate collection, washing and neutralization. The soybean protein extracted by the technology has the characteristics of low phytic acid content, high emulsibility, low extraction cost, environmental friendliness and the like, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing and relates to a method for separating and extracting low-phytic acid and high-emulsifying soybean protein. Background Art

[0002] Soy protein, as the most important nutrient in soybeans, is a high-quality plant protein from edible plant sources, accounting for more than 40% of the dry content of soybeans. Because it contains 8 essential amino acids needed by the human body and the amino acid ratio is balanced, it is an ideal edible protein resource.

[0003] Soy protein isolate (SPI) is widely used in the food field. However, its relatively poor solubility and emulsification limit its application in weakly acidic (pH 3-6) food systems. At present, in order to improve the solubility and emulsification of soy protein isolate, industry usually chooses to phosphorylate SPI by adding phosphoryl chloride (POCl3), phosphorus pentoxide (P2O5) and sodium tripolyphosphate (STP) and other phosphorylation reagents. The patent (publication number CN115005318A, publication date September 6, 2022) discloses a method for improving the functional properties of soy protein isolate by combining heat treatment with phosphorylation. After the soy protein isolate is preheated with water, sodium tripolyphosphate (STP) is added and reacted under controlled pH and temperature conditions to obtain phosphorylated soy protein isolate. Its modification technology consumes a lot of energy for the pretreatment of raw materials, and the additional addition of phosphorylation reagents affects food safety.

[0004] Phytate (a cyclic compound containing 6 phosphate groups) content in soybean is as high as 17.9mg / g (dry weight). When soy protein isolate is applied to dairy production, the phytic acid content is too high, which will not only directly affect the solubility characteristics of protein, reduce the content of calcium in dairy products, but also affect the absorption of mineral elements such as Ca, Mg, Zn, Cu and Fe in dairy products by human body to a large extent. Prior art generally adopts the method of phytase treatment to remove phytic acid, which is costly and ineffective, and the phosphate group in phytic acid is also wasted in large quantities. Therefore, it is necessary to establish a method for improving the emulsification of soy protein using the phytic acid of soybean itself. Summary of the invention

[0005] In view of the above technical problems, the present invention provides a method for separating and extracting low-phytic acid and high-emulsifying soybean protein with low production cost and environmental friendliness.

[0006] The present invention provides a method for separating and extracting low-phytic acid and high-emulsifying soybean protein, comprising the following steps:

[0007] S1: soybean meal slurry preparation, used to prepare low-temperature defatted soybean meal slurry;

[0008] S2: microwave modification, for subjecting the prepared low-temperature defatted soybean meal slurry to microwave treatment to obtain modified soybean meal slurry;

[0009] S3: alkali extraction, for treating the obtained modified soybean meal slurry with alkali and filtering it to obtain a supernatant;

[0010] S4: phytase hydrolysis, for hydrolyzing phytate in the supernatant by adding phytase to obtain a phytase hydrolyzate;

[0011] S5: phosphorylation modification, which is used to adjust the pH value to make the phosphoric acid in the phytase hydrolyzate and the soy protein isolate undergo an esterification reaction to obtain a phosphorylation modified solution;

[0012] S6: Acid precipitation is used to add hydrochloric acid to the phosphorylated modified solution to adjust the pH value, so that the phosphorylated soybean protein can be flocculated and precipitated to obtain low-phytic acid and highly emulsifiable phosphorylated soybean protein.

[0013] Preferably, in step S1, the preparation of the soybean meal slurry comprises the following steps: low-temperature defatted soybean meal is crushed, sieved and dried to obtain soybean powder; water is added to the soybean powder at a solid-liquid ratio of 1:9 to 12 (w / v), and the mixture is stirred sufficiently to prepare low-temperature defatted soybean meal slurry.

[0014] Further preferably, in step S1, the preparation of the soybean meal slurry comprises the following steps: low-temperature defatted soybean meal is crushed, sieved and dried to obtain soybean powder; water is added to the soybean powder at a solid-liquid ratio of 1:11 (w / v), and the mixture is stirred sufficiently to prepare low-temperature defatted soybean meal slurry.

[0015] Preferably, in step S2, the microwave modification comprises the following steps: treating the low-temperature defatted soybean meal slurry prepared in S1 with 800-1200 W microwaves for 40-60 s to change the protein structure and obtain modified soybean meal slurry.

[0016] Further preferably, in step S2, the microwave modification comprises the following steps: treating the low-temperature defatted soybean meal slurry prepared in S1 with 1100 W microwaves for 50 s to change the protein structure and obtain modified soybean meal slurry.

[0017] Preferably, in step S3, the alkali extraction comprises the following steps: adjusting the pH value of the modified soybean meal slurry to 8 with NaOH, heating and stirring in a 40-55° C. water bath for 30-45 min, coarse filtering with a 160-mesh filter cloth, and centrifuging the filtrate to obtain a supernatant.

[0018] Further preferably, in step S3, the alkali extraction comprises the following steps: adjusting the pH value of the modified soybean meal slurry to 8 with NaOH, heating and stirring in a 50° C. water bath for 40 min, coarse filtering with a 160-mesh filter cloth, and centrifuging the filtrate to obtain a supernatant.

[0019] Preferably, in step S4, the phytate enzymatic hydrolysis comprises the following steps: adjusting the pH value of the supernatant obtained in S3 to 4.8-6.0 with 10-12% hydrochloric acid, adding phytase to perform enzymatic hydrolysis in a 30-40° C. water bath for 60-90 min, and adding phytase in an amount of 3000-4000 U / kg soybean powder.

[0020] Further preferably, in step S4, the phytate enzymatic hydrolysis comprises the following steps: adjusting the pH value of the supernatant obtained in S3 to 5.5 with 10% hydrochloric acid, adding phytase and performing enzymatic hydrolysis in a 37° C. water bath for 80 min, wherein the amount of phytase added is 3750 U / kg soybean powder.

[0021] Preferably, in step S4, the phytase is 2 to 3 of phytate-3-phosphohydrolase, phytate-6-phosphohydrolase and Aspergillus niger phytase.

[0022] Further preferably, in step S4, during the enzymatic hydrolysis of phytate, the phytase used is composed of phytate-3-phosphohydrolase and phytate-6-phosphohydrolase, and the activity unit ratio of the two enzymes is 5:1 (U:U).

[0023] Or, further preferably, in step S4, during the enzymatic hydrolysis of phytate, the phytase used consists of phytate-3-phosphohydrolase, phytate-6-phosphohydrolase and Aspergillus niger phytase, and the ratio of the three enzyme activity units is 4:2:1 (U:U:U).

[0024] Preferably, in step S4, the phytase is a plant-derived phytase, and the preparation method thereof is as follows: after washing the soybeans, disinfecting them with a 1% sodium hypochlorite solution for 15 minutes, rinsing them with water until they are neutral, and then soaking them at a material / water ratio of 1:3.6 (v / v); preheating the water to 30°C before soaking; placing the soaked soybeans in a germination machine at a temperature of 25-30°C and germinating in the dark for 4-6 days; freeze-drying the germinated soybeans, crushing them, and then passing them through a 60-mesh sieve; adding water at a solid-liquid ratio of 1:6 (w / v), mixing them, and fully stirring them; centrifuging the resulting slurry at 5000r / min for 10 minutes, removing the residue, and obtaining the plant-derived phytase.

[0025] Preferably, the phosphorylation modification in step S5 comprises the following steps: adjusting the pH value of the phytase hydrolyzate in S4 to 7.5-8.5 with NaOH, stirring for 1-2 hours at a temperature of 30-45° C. and a stirring speed of 150-200 rpm, so that the phosphoric acid released by the enzymatic decomposition in the solution undergoes an esterification reaction with the soy protein isolate.

[0026] Further preferably, the phosphorylation modification in step S5 comprises the following steps: adjusting the pH value of the phytase hydrolyzate in S4 to 8.0 with NaOH, stirring for 1.5 hours at a temperature of 40° C. and a stirring speed of 180 rpm, so that the phosphoric acid released by the enzymatic decomposition in the solution undergoes an esterification reaction with the soy protein isolate.

[0027] Preferably, in step S6, the acid precipitation is a solution after phosphorylation modification, and the pH value is adjusted using hydrochloric acid; the hydrochloric acid concentration is 12-15%, and the pH value is adjusted to 4-4.5; after stirring in a water bath at 35-55°C, it is allowed to stand for 40-55 minutes, and the phosphorylated protein becomes flocculated, and the curd precipitate is collected by centrifugation; the collected curd precipitate is washed with water and neutralized to obtain low-phytic acid high-emulsifying soy protein.

[0028] Further preferably, in step S6, the acid precipitation is a solution after phosphorylation modification, and the pH value is adjusted using hydrochloric acid; the hydrochloric acid concentration is 15%, and the pH value is adjusted to 4.5; after stirring in a 40°C water bath, it is allowed to stand for 45 minutes, and the phosphorylated protein becomes flocculated, and the curd precipitate is collected by centrifugation; the collected curd precipitate is washed with water and neutralized to obtain low-phytic acid and high-emulsifying soy protein.

[0029] Compared with the prior art, the separation and extraction method of the low-phytic acid high-emulsifying soybean protein of the present invention has the following beneficial effects:

[0030] 1. The present invention realizes the extraction of low-phytic acid and high-emulsifying soybean protein, and solves the problems of high production cost and complicated steps in the previous technology of extracting soybean protein first and then phosphorylating and modifying it.

[0031] 2. The present invention utilizes phytic acid contained in soybeans themselves, and through the hydrolysis of phytase, the removed phosphoric acid is combined with certain amino acid sites of the protein in the process of soybean protein separation to form phosphorylated soybean protein isolate, thereby improving the emulsification of soybean protein and significantly reducing the phytic acid content. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Technical flow chart of the present invention. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the present invention is described in detail below in conjunction with specific embodiments.

[0034] First, the term "one embodiment" or "embodiment" as used herein refers to a specific feature or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0035] Secondly, the present invention is described in detail using a process flow diagram, etc. When describing the embodiments of the present invention in detail, for the sake of convenience, a process flow diagram representing a method for separating and extracting low-phytic acid high-emulsifying soybean protein will not be described according to actual use, and the technical process diagram is only an example, which should not limit the scope of protection of the present invention. In addition, in actual production, reaction equipment, reaction reagent dosage, production operation, etc. should be included.

[0036] Example 1

[0037] like Figure 1 As shown, the present invention provides a method for separating and extracting low-phytic acid and high-emulsifying soybean protein, and the separation and extraction method comprises the following steps:

[0038] S1: soybean meal slurry preparation, used to prepare low-temperature defatted soybean meal slurry;

[0039] S2: microwave modification, for subjecting the prepared low-temperature defatted soybean meal slurry to microwave treatment to obtain modified soybean meal slurry;

[0040] S3: alkali extraction, for treating the obtained modified soybean meal slurry with alkali and filtering it to obtain a supernatant;

[0041] S4: phytase hydrolysis, for hydrolyzing phytate in the supernatant by adding phytase to obtain a phytase hydrolyzate;

[0042] S5: phosphorylation modification, which is used to adjust the pH value to allow the hydrolyzate to fully undergo esterification reaction to obtain a phosphorylation modified solution;

[0043] S6: Acid precipitation is used to add hydrochloric acid to the phosphorylated modified solution to adjust the pH value, so that the phosphorylated soybean protein can be flocculated and precipitated to obtain low-phytic acid and highly emulsifiable phosphorylated soybean protein.

[0044] Among them, in step S1, the preparation of soybean meal slurry includes the following steps: low-temperature defatted soybean meal is crushed, sieved and dried to obtain soybean powder, water is added to the soybean powder at a solid-liquid ratio of 1:11 (w / v), and the mixture is fully stirred to prepare low-temperature defatted soybean meal slurry.

[0045] In step S2, microwave modification includes the following steps: treating the low-temperature defatted soybean meal slurry prepared in S1 with 1100 W microwaves for 50 seconds to change the protein structure and obtain modified soybean meal slurry.

[0046] In step S3, the alkaline extraction includes the following steps: adjusting the pH value of the modified soybean meal slurry to 8 with NaOH, heating and stirring in a 50°C water bath for 40 minutes, coarse filtering with a 160-mesh filter cloth to remove surface impurities, and centrifuging the filtrate in a 4000r / min centrifuge for 20 minutes to obtain a supernatant after separation; and transferring the supernatant to a clean container for storage.

[0047] In step S4, phytase hydrolysis comprises the following steps: adjusting the pH value of the supernatant obtained in S3 to 5.5 with 10% hydrochloric acid, adding phytase to perform enzymolysis in a 37° C. water bath for 80 min, wherein the amount of phytase added is 3000-4000 U / kg of soybean powder; preferably, the amount of phytase used is 3750 U per kilogram of soybean powder;

[0048] Wherein, in step S4, the phytase is composed of phytate-3-phosphohydrolase and phytate-6-phosphohydrolase, and the activity unit ratio of the two enzymes is 5:1 (U:U).

[0049] In step S5, the phosphorylation modification in step S5 includes the following steps: adjusting the pH value of the phytase hydrolyzate in S4 to 8.0 with NaOH, stirring for 1.5 hours at a temperature of 40° C. and a stirring speed of 180 rpm, so that the phosphoric acid released by the enzymatic decomposition in the solution reacts with the soy protein isolate for esterification.

[0050] In step S6, the acid precipitation is a solution after phosphorylation modification, and the pH value is adjusted using hydrochloric acid; the hydrochloric acid concentration is 15%, and the pH value is adjusted to 4.5; after stirring in a 40°C water bath, it is allowed to stand for 45 minutes, and the phosphorylated protein becomes flocculated, and the curd precipitate is collected by centrifugation; the collected curd precipitate is washed with water and neutralized to obtain low-phytic acid high-emulsifying soy protein.

[0051] Embodiment 2

[0052] The phytase in this example uses low-temperature grinding liquid of germinated soybeans as the phytase enzyme source (containing inositol hexaphosphate-3-phosphohydrolase and inositol hexaphosphate-6-phosphohydrolase), and the remaining steps are the same as those in Example 1.

[0053] Wherein, the steps of preparing plant-derived phytase are as follows:

[0054] After washing the soybeans, the soybeans are disinfected with a 1% sodium hypochlorite solution for 15 minutes, rinsed with water until neutral, and then soaked at a material / water ratio of 1:3.6 (v / v); the water is preheated to 30°C before soaking; the soaked soybeans are placed in a germination machine at a temperature of 25-30°C to germinate for 4-6 days in the dark; the germinated soybeans are freeze-dried, crushed, and passed through a 60-mesh sieve; water is added at a solid-liquid ratio of 1:6 (w / v), mixed, and fully stirred, and the obtained slurry is centrifuged at 5000r / min for 10 minutes, and the residue is removed to obtain plant-based phytase.

[0055] Embodiment 3

[0056] The phytase in this example uses Aspergillus niger phytase, and the other steps are the same as those in Example 1, thereby preparing low-phytic acid and high-emulsifying soybean protein.

[0057] Comparative Example 1

[0058] A method for separating and extracting low-phytic acid and high-emulsifying soybean protein, the preparation method of which is as follows:

[0059] Compared with Example 1, the only difference is that the S5 phosphorylation modification step is omitted, and the remaining operations are the same as those in Example 1.

[0060] Comparative Example 2

[0061] A method for separating and extracting low-phytic acid and high-emulsifying soybean protein, the preparation method of which is as follows:

[0062] Compared with Example 1, the only difference is that the S4 phytate enzymatic hydrolysis step is omitted, and the remaining operations are the same as those in Example 1.

[0063] Comparative test example

[0064] The low-phytic acid high-emulsifying phosphorylated soybean protein obtained in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2 were subjected to comparative tests, and the test contents and results are as follows:

[0065] 1. Determination of emulsification activity and emulsification stability:

[0066] 100 mL of protein suspension with a mass concentration of 0.1 g / mL was prepared with a phosphate buffer solution with a pH value of 7.0 and a mass concentration of 0.1 mol / L. 30 mL of protein solution was taken in a high-speed homogenizer, and 10 mL of soybean oil was added. The solution was homogenized at 10000 r / min for 1 min to form an emulsion. After homogenization, 100 μL of the solution was drawn from the bottom at 0 min and 10 min, respectively, and dispersed in 10 mL of SDS solution with a mass concentration of 0.1 g / mL. The absorbance was measured at a wavelength of 500 nm (the average value was taken after 3 measurements). The calculation formulas for emulsification activity and emulsification stability are as follows:

[0067] E A =100A0

[0068] Where E A - emulsifying activity;

[0069] E S —Emulsion stability, min;

[0070] A0—absorbance at 0 min;

[0071] △T-the time interval between two emulsification tests, 10 min;

[0072] A 10 —Absorbance at 10 min

[0073] 2. Determination of phosphorylation degree

[0074] The phosphorylation degree of the sample is expressed as the bound phosphorus content in the sample, and the phosphorus content is determined by the following method:

[0075] (1) The total phosphorus content in the sample was determined according to GB / T 5009.87-2003.

[0076] (2) Determination of inorganic phosphorus content in samples: Accurately weigh 1g sample (dry basis), place in a 100mL volumetric flask, add 10mL hydrochloric acid and a few drops of nitric acid (1:1), add 30mL of water, add 2 drops of phenolphthalein, add NaOH until it turns light red, then add 0.3mL of nitric acid, dilute with water to the scale, shake well, filter, and discard the initial 30mL filtrate to obtain the sample decomposition solution. Take a certain volume of the decomposition solution and determine the inorganic phosphorus content by the platinum blue colorimetric method. The phosphorylation degree is calculated by the formula:

[0077] P E =P t -P i

[0078] Where P E —Phosphorylation degree, mg / g;

[0079] P t —Total phosphorus content, mg / g;

[0080] P i —Inorganic phosphorus content, mg / g

[0081] The measurement results are shown in Table 1.

[0082] Table 1

[0083]

[0084] As shown in Table 1, the emulsifying activity and emulsifying stability of Example 1, Example 2 and Example 3 are higher than those of Comparative Example 1 and Comparative Example 2. This is because in the embodiment, the soy protein isolate slurry obtained from low-temperature defatted soybean meal is treated with phytase (phytate-3-phosphohydrolase, phytate-6-phosphohydrolase and / or Aspergillus niger phytase) after microwave treatment, and more phosphate is enzymatically released from the phytic acid molecule, thereby increasing the phosphorylation modification effect, while there is no phosphorylation modification step in Comparative Example 1, and there is no phytate enzymatic hydrolysis step in Comparative Example 2, so the emulsifying activity and emulsifying stability are not as good as those of the embodiment. The test results show that microwave-assisted, phytase enzymatic hydrolysis combined with phosphorylation modification can significantly improve the emulsifying activity of soy protein isolate.

[0085] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for separating and extracting low-phytic acid and high-emulsifying soybean protein, characterized in that: The steps include: S1: soybean meal slurry preparation, used to prepare low-temperature defatted soybean meal slurry; S2: microwave modification, for subjecting the prepared low-temperature defatted soybean meal slurry to microwave treatment to obtain modified soybean meal slurry; S3: alkali extraction, for treating the obtained modified soybean meal slurry with alkali and filtering it to obtain a supernatant; S4: phytase hydrolysis, for hydrolyzing phytate in the supernatant by adding phytase to obtain a phytase hydrolyzate; S5: phosphorylation modification, which is used to adjust the pH value to make the phosphoric acid in the phytase hydrolyzate and the soy protein isolate undergo an esterification reaction to obtain a phosphorylation modified solution; S6: Acid precipitation is used to add hydrochloric acid to the phosphorylated modified solution to adjust the pH value, so that the phosphorylated soybean protein can be flocculated and precipitated to obtain low-phytic acid and highly emulsifiable phosphorylated soybean protein.

2. The separation and extraction method according to claim 1, characterized in that: In step S1, the soybean meal slurry preparation comprises the following steps: The low-temperature defatted soybean meal is crushed, sieved and dried to obtain soybean powder; water is added to the soybean powder at a solid-liquid ratio of 1:9-12 (w / v), and the mixture is fully stirred to prepare a low-temperature defatted soybean meal slurry.

3. The separation and extraction method according to claim 1, characterized in that: In step S2, the microwave modification includes the following steps: treating the low-temperature defatted soybean meal slurry prepared in S1 with 800-1200W microwaves for 40-60s to change the protein structure and obtain modified soybean meal slurry.

4. The separation and extraction method according to claim 1, characterized in that: In step S3, the alkali extraction includes the following steps: adjusting the pH value of the modified soybean meal slurry to 8 with NaOH, heating and stirring in a 40-55° C. water bath for 30-45 minutes, coarse filtering with a 160-mesh filter cloth, and centrifuging the filtrate to obtain a supernatant.

5. The separation and extraction method according to claim 1, characterized in that: In step S4, the phytate enzymatic hydrolysis comprises the following steps: adjusting the pH value of the supernatant obtained in S3 to 4.8-6.0 with 10-12% hydrochloric acid, adding phytase to perform enzymatic hydrolysis in a 30-40° C. water bath for 60-90 minutes, and adding phytase in an amount of 3000-4000 U / kg soybean powder.

6. The separation and extraction method according to claim 1, characterized in that: In step S4, the phytase is 2 to 3 of phytate-3-phosphohydrolase, phytate-6-phosphohydrolase and Aspergillus niger phytase.

7. The separation and extraction method according to claim 6, characterized in that: In step S4, during the enzymatic hydrolysis of phytate, the phytase consists of phytate-3-phosphohydrolase and phytate-6-phosphohydrolase, and the activity unit ratio of the two enzymes is 5:1 (U:U); or, the phytase consists of phytate-3-phosphohydrolase, phytate-6-phosphohydrolase and Aspergillus niger phytase, and the activity units of the three enzymes are in a ratio of 4:2:1 (U:U:U).

8. The separation and extraction method according to claim 1, characterized in that: In step S4, the phytase is a plant-based phytase, and the preparation method thereof is as follows: after washing the soybeans, disinfecting them with a 1% sodium hypochlorite solution for 15 minutes, rinsing them with water until they are neutral, and then soaking them at a material / water ratio of 1:3.6 (v / v); preheating the water to 30°C before soaking; placing the soaked soybeans in a germination machine at a temperature of 25-30°C to germinate for 4-6 days in the dark; freeze-drying the germinated soybeans, crushing them, and then passing them through a 60-mesh sieve; adding water at a solid-liquid ratio of 1:6 (w / v), mixing them, and fully stirring them; centrifuging the resulting slurry at 5000r / min for 10 minutes, removing the residue, and obtaining the plant-based phytase.

9. The separation and extraction method according to claim 1, characterized in that: In step S5, the phosphorylation modification includes the following steps: adjusting the pH value of the phytase hydrolyzate in S4 to 7.5-8.5 with NaOH, stirring for 1-2 hours at a temperature of 30-45° C. and a stirring speed of 150-200 rpm, so that the phosphoric acid released by the enzymatic decomposition in the solution undergoes an esterification reaction with the soy protein isolate.

10. The separation and extraction method according to claim 1, characterized in that: In step S6, the acid precipitate is a phosphorylated solution, and the pH value is adjusted using hydrochloric acid; the hydrochloric acid concentration is 12-15%, and the pH value is adjusted to 4-4.5; after stirring in a 35-55° C. water bath, the solution is allowed to stand for 40-55 minutes, and the phosphorylated protein becomes flocculated. After centrifugation, the curd precipitate is collected; the collected curd precipitate is washed with water and neutralized to obtain low-phytic acid high-emulsifying soy protein.

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