Soybean protein powder with low sensitization and high oxidation resistance and preparation method thereof

Abstract

The invention belongs to the field of food bioengineering, and particularly relates to soybean protein powder with low sensitization and high oxidation resistance and a preparation method of the soybean protein powder. The preparation method comprises the following steps: firstly, uniformly mixing soybean protein with pure water, and then performing ultrasonic treatment to obtain an ultrasonic modified soybean protein solution; and adding the polyphenol solution into the ultrasonic modified soybean protein solution, adjusting the pH value to be alkaline, and fully stirring and reacting at room temperature for 24 hours to obtain the ultrasonic-polyphenol compound modified soybean protein. And dialyzing and freeze-drying to obtain the soybean protein powder with low sensitization and high oxidability. The space structure of the soybean protein is changed by combining ultrasound with the food-borne polyphenol, the prepared soybean protein powder is relatively low in antigenicity, the oxidation resistance and the solubility are improved, and the process is simple, safe and pollution-free.

Description

Technical Field

[0001] The present invention belongs to the field of food bioengineering, and particularly relates to a soybean protein powder with low allergenicity and high antioxidant activity and a preparation method thereof. Background Art

[0002] Soybeans, as a high-quality source of plant protein, are widely used in food processing. However, soybeans are also one of the most important food allergens, being associated with approximately 25% of food allergy reactions (Ding J, Li Y, Zhong L, etal. Unveiling the regulatory mechanism of pulsed electric field modified instant soy milk powder: Exploring allergenicity, conformation, and epitopes[J]. Food Chemistry, 2025, 465: 142071), and having a low allergy threshold. The allergic reactions caused by soybean antigen proteins can harm the body's respiratory, digestive, and skin systems, interfere with human metabolism, and affect growth and health, which severely limits the application of soybeans in food. Therefore, it has certain practical significance to develop soy products with low allergenicity and good functionality by adopting certain processing technical means.

[0003] At present, the methods for reducing food allergenicity mainly include physical methods, chemical methods, and biological methods. These methods can reduce the allergenicity of soy protein to a certain extent. Among them, physical processing technology is considered a technology with less impact on the nutritional quality of food. As one of the most common physical processing technologies, ultrasonic technology mainly causes different degrees of polymerization and depolymerization of the structure of globular proteins through the cavitation effect, thermal effect, and mechanical action generated during the ultrasonic process, achieving the effect of reducing the antigenicity of allergenic proteins. However, a number of studies have shown that the desensitization effect of single ultrasonic treatment is not significant and the efficiency is low. Therefore, it is necessary to strengthen the combination of ultrasonic technology with other technologies to improve the desensitization effect. Polyphenols, as a natural plant active substance with a wide range of sources, are green and safe, and have many beneficial effects such as anti-aging, antioxidant, and antibacterial effects. At the same time, polyphenols have a strong binding affinity for proteins. At present, ultrasonic treatment and polyphenol modification have not been jointly used in the preparation of hypoallergenic soy protein. A large number of studies have shown that the addition of polyphenols can change the structure of soy protein, can reduce the allergenicity of the protein to a certain extent, and improve its functional properties (Pi X, Liu J, Sun Y, et al. Protein modification, IgEbinding capacity, and functional properties of soybean protein upon conjugation with polyphenols [J]. Food Chemistry, 2023, 405: 134820; Lin X, YeL, He K, et al. A new method to reduce allergenicity by improving the functional properties of soybean 7S protein through covalent modification with polyphenols [J]. Food Chemistry, 2022, 373: 131589; Yun Z, Li J, Zhu W, et al. Effects of chlorogenic acid on lowering IgE-binding capacity of soybean 7S: comparison between covalent and noncovalent interaction [J]. Journal of Agricultural and Food Chemistry, 2024, 72(21): 12270-12280).In summary, the ultrasonic treatment has mild conditions, but the desensitization effect is average. The addition of polyphenols does not add too many extra steps, and this treatment method is efficient, mild, safe, and easy to operate, capable of achieving the dual effects of desensitization and improving antioxidant properties. The ultrasonic combined with polyphenol modification technology can effectively reduce the allergenicity of soy protein while improving the functional properties of the protein, expanding the application of soy protein in the food industry. Summary of the Invention

[0004] In order to effectively reduce the allergenicity of soy protein and improve its functionality, the present invention provides a method for preparing a soy protein powder with low allergenicity and high antioxidant properties by ultrasonic combined with polyphenol modification, as well as its preparation method, so as to expand the application of soy protein in food and health products.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: In the first aspect, the present invention provides a method for preparing a soy protein powder with low allergenicity and high antioxidant properties, comprising the following steps: (1) Mix the soy protein powder evenly with pure water, and then perform ultrasonic treatment to obtain an ultrasonically modified soy protein solution.

[0006] In this step, the soy protein powder is at least one of soy protein isolate, defatted soybean meal, 7S protein, and 11S protein. Among them, 7S and 11S are the main components of soy protein isolate.

[0007] In this step, when the soy protein concentration is between 4% and 10% (w / v), it can better disperse to form a stable liquid, avoiding a decrease in subsequent processing efficiency due to too low a concentration. An excessively high protein concentration (exceeding 10%) will cause the solution viscosity to be too high, affecting the propagation effect of ultrasonic waves, thereby reducing the efficiency of ultrasonic modification.

[0008] In this step, before ultrasonic treatment, the mixed solution can be stirred. Stirring can disperse the soy protein particles in advance, improve the dispersion uniformity, avoid aggregation, make the ultrasonic action more uniform and efficient, and thus improve the final modification effect.

[0009] In this step, the ultrasonic treatment is: under ice-water bath conditions, treat with an ultrasonic power of 200 - 600 W for 10 - 30 min. Ultrasonic treatment will generate heat, and the solution temperature will rise significantly. Soy protein is a heat-sensitive protein. The ice-water bath can control the temperature rise, avoid protein thermal denaturation, make the modification process more controllable, enhance the ultrasonic modification effect, avoid protein oxidation and adverse side reactions, and improve the efficiency of subsequent polyphenol modification.

[0010] (2) Add the polyphenol solution to the ultrasonically modified soy protein solution obtained in (1), adjust the pH of the solution to alkaline, and stir and react at room temperature to obtain an ultrasonically - polyphenol composite - modified soy protein solution.

[0011] In this step, the polyphenols are at least one of chlorogenic acid (CHA), epigallocatechin gallate (EGCG), trans-cinnamic acid (TCA), and trans-ferulic acid (TFA).

[0012] In this step, adjusting the solution pH to alkaline is to accelerate the oxidation of polyphenols to quinones, improve the covalent binding efficiency with proteins, promote the unfolding of protein conformation, enhance the exposure of binding sites, improve the modification effect, and avoid non-specific aggregation, ultimately obtaining a more stable and highly functional ultrasonic-polyphenol composite modified soy protein.

[0013] In this step, the volume of the added polyphenols is the same as the volume of the ultrasonic modified soy protein solution, and the concentration of the added polyphenols is not higher than 24 mmol / L.

[0014] (3) Dialyze the soy protein solution obtained in (2) to remove the unbound polyphenols, and then freeze-dry to obtain the ultrasonic-polyphenol modified soy protein powder. The specific operation of dialysis is as follows: Pour the soy protein solution obtained in (2) into a dialysis bag and dialyze at 4°C for 1 - 2 days.

[0015] In the second aspect, the present invention provides a soy protein powder prepared by the above method. The obtained soy protein powder has significantly reduced allergenicity, and at the same time, its antioxidant capacity and solubility are improved.

[0016] The beneficial effects of the present invention are as follows: (1) The present invention adopts a method of ultrasonic combined with polyphenol modification to reduce the allergenicity of soy protein and improve its antioxidant performance. Ultrasonic treatment, as a physical modification method, has mild and controllable conditions, can dissociate protein subunits and expose more reaction sites, thereby improving the binding efficiency of polyphenols. Polyphenols, as natural active substances, are safe and environmentally friendly, not only having antioxidant and antibacterial effects, but also can bind to proteins through hydrogen bonds, hydrophobic interactions, covalent crosslinking, etc., enhancing the functional properties of proteins. Using short-time ultrasonic (10 - 30 min) combined with polyphenol modification can achieve effective modification without affecting the functionality of the protein and significantly improve the biological properties of soy protein.

[0017] (2) The allergenicity of the soy protein powder obtained in the present invention is significantly reduced, while its antioxidant capacity and solubility are improved. The experimental results show that the combined treatment of ultrasound and polyphenols can reduce the antigenicity of 7S and 11S proteins by 78.14% and 76.29% respectively, indicating a significant reduction in allergenicity. At the same time, this treatment increases the DPPH and ABTS radical scavenging rates, which can be increased by 198.08% and 329.34% respectively, indicating enhanced antioxidant capacity. In addition, the solubility measured at room temperature can be increased by 181.54%, which is helpful for its dissolution stability and processing adaptability in food systems.

[0018] (3) The soy protein powder prepared in the present invention has broader application potential. Due to its reduced allergenicity, it can be used as a low-allergenic protein ingredient in infant foods, special medical foods, and foods for sensitive populations, broadening the scope of use of soy protein. At the same time, its high antioxidant activity and solubility make it suitable for functional protein beverages, plant-based meat products, sports nutrition foods, etc., improving the processing adaptability and market value of soy protein. Brief Description of the Drawings

[0019] Figure 1 Effect of combined treatment of different concentrations of CHA and ultrasound on the antigenicity of soy protein isolate.

[0020] Figure 2 Effect of combined treatment of different concentrations of CHA and ultrasound on the solubility of soy protein isolate.

[0021] Figure 3 Effect of combined treatment of different concentrations of CHA and ultrasound on the antioxidant property of soy protein isolate.

[0022] In the figure, 1: untreated soy protein isolate; 2: single ultrasound modification treatment (400 W); 3: single CHA modification treatment (24 mmol / L); 4: combined treatment of 2 mmol / L CHA and ultrasound; 5: combined treatment of 5 mmol / L CHA and ultrasound; 6: combined treatment of 12 mmol / L CHA and ultrasound; 7: combined treatment of 24 mmol / L CHA and ultrasound. Detailed Embodiments

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] In the examples, the ice-water bath refers to: placing the mixed solution of soy protein isolate and water in an ice-water bath in which ice and distilled water are mixed in equal proportions, and ensuring that the temperature of the mixed solution of soy protein isolate and water is maintained between 4°C and 10°C.

[0025] Example 1 Select 10 g of commercially available soy protein isolate, add it to 100 mL of distilled water, stir evenly for 2 h, then under ice-water bath conditions, ultrasonically treat (ultrasonic power is set to 400 W) for 15 min to obtain an ultrasonically modified soy protein solution; then add an equal volume of CHA solution, mix well and adjust the pH of the solution to 9.0 with 2 mmol / L NaOH, stir and react at room temperature for 24 h. After the reaction, transfer the solution to a dialysis bag with a molecular weight cut-off of 3500 Da and dialyze in a 4°C incubator for 48 h. Change the water every 4 h during the dialysis process to remove the unbound CHA. Finally, freeze-dry the solution to obtain ultrasonically-polyphenol modified soy protein powder.

[0026] At the same time, to compare the effects of ultrasonic treatment alone or CHA treatment on soy protein isolate, the following control experiments were set up: Ultrasonic treatment alone: Only ultrasonically treat the mixed solution of soy protein isolate and water. The specific operation is: add 10 g of soy protein isolate to 100 mL of distilled water, stir evenly for 2 h, then under ice-water bath conditions, ultrasonically treat (ultrasonic power is set to 400 W) for 15 min to obtain an ultrasonically modified soy protein solution, and then freeze-dry the solution to obtain ultrasonically modified soy protein powder. CHA treatment alone: Add 10 g of soy protein isolate to 100 mL of distilled water, stir evenly for 2 h, directly add an equal volume of CHA, and adjust the pH of the solution to 9.0, stir and react at room temperature for 24 h, then perform dialysis treatment, and then freeze-dry the dialyzed solution to obtain polyphenol-modified soy protein powder. The concentrations of the CHA solution are set to 2 mmol / L, 5 mmol / L, 12 mmol / L, and 24 mmol / L.

[0027] Regarding the antigenicity of soy protein isolate, measured by the indirect competitive ELISA method, compared with untreated soy protein isolate, ultrasonic single modification treatment, and polyphenol single modification treatment, after soy protein isolate was treated with different concentrations of CHA combined with ultrasonic treatment, the antigenicity of the main soy allergenic proteins 7S and 11S was significantly reduced, and the antigenicity of the soy protein isolate treated with 24 mmol / L CHA combined with ultrasonic treatment was the lowest.

[0028] Compared with untreated soy protein isolate, the antigenicity of the main allergenic protein 7S in soybeans decreased by 6.17% and that of 11S decreased by 10.33% after single ultrasonic modification; after single treatment with 24 mmol / L CHA, the antigenicity of the main allergenic protein 7S in soybeans decreased by 31.85% and that of 11S decreased by 31.76%; after combined treatment with ultrasound-polyphenol (24 mmol / L CHA), the antigenicity of the main allergenic protein 7S in soybeans decreased by 74.84% and that of 11S decreased by 76.29%, as Figure 1 shown.

[0029] Regarding the solubility of soy protein isolate, compared with untreated soy protein isolate and single ultrasonic modification treatment, after treating soy protein isolate with different concentrations of CHA combined with ultrasound, the solubility of soy protein isolate at room temperature increased significantly. Among them, the solubility of soy protein isolate treated with 24 mmol / L CHA combined with ultrasound was the highest, and its solubility increased by 181.54% compared with untreated soy protein isolate, as Figure 2 shown.

[0030] Regarding the antioxidant property of soy protein isolate, compared with untreated soy protein isolate and single ultrasonic modification treatment, after treating soy protein isolate with different concentrations of CHA combined with ultrasound, the antioxidant property of soy protein isolate (DPPH free radical scavenging rate, ABTS free radical scavenging rate) increased significantly. Among them, the soy protein isolate treated with 24 mmol / L CHA combined with ultrasound had the strongest antioxidant property. Compared with untreated soy protein isolate, its DPPH free radical scavenging rate increased by 167.85% and its ABTS free radical scavenging rate increased by 329.34%, as Figure 3 shown.

[0031] Example 2 Select 10 g of commercially available soy protein isolate, add it to 100 mL of distilled water, stir evenly for 2 h, and then treat it with ultrasound (ultrasonic power set to 400 W) for 15 min under ice-water bath conditions to obtain an ultrasonically modified soy protein solution; then add an equal volume of EGCG solution, mix well and adjust the pH of the solution to 9.0 with 2 mmol / L NaOH, and stir and react at room temperature for 24 h. After the reaction, transfer the solution to a dialysis bag with a molecular weight cut-off of 3500 Da and dialyze it in a constant temperature incubator at 4°C for 48 h. Change the water every 4 h during the dialysis process to remove the unbound EGCG. Finally, freeze-dry the solution to obtain ultrasonically modified soy protein powder with polyphenol.

[0032] Meanwhile, to compare the effects of individual ultrasound or EGCG treatment on soy protein isolate, the following control experiments were set up: Individual ultrasound treatment: Only the mixed solution of soy protein isolate and water was treated with ultrasound. The specific operation was as follows: 10 g of soy protein isolate was added to 100 mL of distilled water, stirred evenly for 2 h, and then treated with ultrasound (ultrasound power was set at 400 W) for 15 min under ice-water bath conditions to obtain an ultrasonically modified soy protein solution. Then the solution was freeze-dried to obtain ultrasonically modified soy protein powder. Individual EGCG treatment: 10 g of soy protein isolate was added to 100 mL of distilled water, stirred evenly for 2 h, and then an equal volume of EGCG was directly added, and the pH of the solution was adjusted to 9.0. The solution was stirred and reacted at room temperature for 24 h, then dialyzed, and then the dialyzed solution was freeze-dried to obtain polyphenol-modified soy protein powder. The concentration of the EGCG solution was set at 2 mmol / L, 5 mmol / L, 12 mmol / L, and 24 mmol / L.

[0033] Regarding the antigenicity of soy protein isolate, as measured by indirect competitive ELISA, compared with untreated soy protein isolate, single ultrasonic modification treatment, and single polyphenol modification treatment, after soy protein isolate was treated with different concentrations of EGCG combined with ultrasound, the antigenicity of the main soy allergenic proteins 7S and 11S decreased significantly, and among them, the antigenicity of soy protein isolate treated with 5 mmol / L EGCG combined with ultrasound was the lowest. Compared with untreated soy protein isolate, after single treatment with 5 mmol / L EGCG, the antigenicity of the main soy allergenic protein 7S decreased by 16.06%, and the antigenicity of 11S decreased by 24.11%; after combined treatment with ultrasound-polyphenol (5 mmol / L EGCG), the antigenicity of the main soy allergenic protein 7S decreased by 66.29%, and the antigenicity of 11S decreased by 56.77%.

[0034] Regarding the solubility and antioxidant properties of soy protein isolate, compared with untreated soy protein isolate, single ultrasonic modification, and single polyphenol modification, after soy protein isolate was treated with different concentrations of EGCG combined with ultrasound, the solubility of soy protein isolate at room temperature increased significantly, and among them, the solubility of soy protein isolate treated with 5 mmol / L EGCG combined with ultrasound was the highest. Specifically, compared with untreated soy protein isolate, its solubility increased by 54.49% at room temperature; compared with untreated soy protein isolate, the DPPH free radical scavenging rate of soy protein isolate treated with 5 mmol / L EGCG combined with ultrasound increased by 198.08%, and the ABTS free radical scavenging rate increased by 56.06%, and the antioxidant performance was significantly improved.

[0035] Example 3 Select 10 g of commercially available soy protein isolate and add it to 100 mL of distilled water. After stirring evenly for 2 h, ultrasonically treat it (ultrasonic power is set to 400 W) for 15 min under ice-water bath conditions to obtain an ultrasonically modified soy protein solution; then add an equal volume of TCA solution, mix well and adjust the pH of the solution to 9.0 with 2 mmol / L NaOH, and stir and react at room temperature for 24 h. After the reaction, transfer the solution to a dialysis bag with a molecular weight cut-off of 3500 Da and dialyze it in an incubator at 4°C for 48 h. Change the water every 4 h during the dialysis process to remove the unbound TCA. Finally, freeze-dry the solution to obtain ultrasonically-polyphenol modified soy protein powder.

[0036] Meanwhile, to compare the effects of ultrasonic treatment or TCA treatment alone on soy protein isolate, the following control experiments were set up: Ultrasonic treatment alone: Only ultrasonically treat the mixed solution of soy protein isolate and water. The specific operation is as follows: Add 10 g of soy protein isolate to 100 mL of distilled water, stir evenly for 2 h, and then ultrasonically treat it (ultrasonic power is set to 400 W) for 15 min under ice-water bath conditions to obtain an ultrasonically modified soy protein solution, and then freeze-dry the solution to obtain ultrasonically modified soy protein powder. TCA treatment alone: Add 10 g of soy protein isolate to 100 mL of distilled water, stir evenly for 2 h, directly add an equal volume of TCA, and adjust the pH of the solution to 9.0, stir and react at room temperature for 24 h, then perform dialysis treatment, and finally freeze-dry the dialyzed solution to obtain polyphenol-modified soy protein powder. The concentrations of the TCA solution are set to 2 mmol / L, 5 mmol / L, 12 mmol / L, and 24 mmol / L.

[0037] For the antigenicity of soy protein isolate, it was measured by indirect competitive ELISA. Compared with untreated soy protein isolate, single ultrasonic modification treatment, and single polyphenol modification treatment, after treating soy protein isolate with different concentrations of TCA combined with ultrasonic treatment, the antigenicity of the main soy allergenic proteins 7S and 11S decreased significantly, and the antigenicity of soy protein isolate treated with 24 mmol / L TCA combined with ultrasonic treatment was the lowest. Compared with untreated soy protein isolate, after single treatment with 24 mmol / L TCA, the antigenicity of the main soy allergenic protein 7S decreased by 20.07% and that of 11S decreased by 31.15%; after ultrasonic-polyphenol (24 mmol / L TCA) combined treatment, the antigenicity of the main soy allergenic protein 7S decreased by 58.66% and that of 11S decreased by 67.53%.

[0038] Regarding the solubility and antioxidant properties of soy protein isolate, compared with untreated soy protein isolate, single ultrasound treatment, and single polyphenol modification treatment, after treating soy protein isolate with different concentrations of TCA combined with ultrasound, the solubility of soy protein isolate at room temperature was significantly increased. Among them, the solubility of soy protein isolate treated with 24 mmol / L TCA combined with ultrasound was the highest. Specifically, compared with untreated soy protein isolate, its solubility increased by 141.54% at room temperature. Compared with untreated soy protein isolate, the DPPH radical scavenging rate of soy protein isolate treated with 24 mmol / L TCA combined with ultrasound increased by 137.46%, and the ABTS radical scavenging rate increased by 193.61%, indicating a significant improvement in antioxidant performance.

[0039] Example 4 Select 10 g of commercially available soy protein isolate and add it to 100 mL of distilled water. After stirring evenly for 2 h, ultrasonically treat it (ultrasonic power is set to 400 W) for 15 min under ice-water bath conditions to obtain an ultrasonically modified soy protein solution. Then add an equal volume of TFA solution, mix well, and adjust the pH of the solution to 9.0 with 2 mmol / L NaOH, and stir and react at room temperature for 24 h. After the reaction is completed, transfer the solution to a dialysis bag with a molecular weight cut-off of 3500 Da and dialyze it in a constant temperature incubator at 4°C for 48 h. Change the water every 4 h during the dialysis process to remove the unbound TFA. Finally, freeze-dry the solution to obtain ultrasonically-polyphenol modified soy protein powder.

[0040] At the same time, to compare the effects of single ultrasound or TFA treatment on soy protein isolate, the following control experiments were set up: Single ultrasound treatment: Only ultrasonically treat the mixed solution of soy protein isolate and water. The specific operation is as follows: Add 10 g of soy protein isolate to 100 mL of distilled water, stir evenly for 2 h, and then ultrasonically treat it (ultrasonic power is set to 400 W) for 15 min under ice-water bath conditions to obtain an ultrasonically modified soy protein solution, and then freeze-dry the solution to obtain ultrasonically modified soy protein powder. Single TFA treatment: Add 10 g of soy protein isolate to 100 mL of distilled water, stir evenly for 2 h, directly add an equal volume of TFA, and adjust the pH of the solution to 9.0, stir and react at room temperature for 24 h, then perform dialysis treatment, and finally freeze-dry the dialyzed solution to obtain polyphenol-modified soy protein powder. The concentrations of the TFA solution are set to 2 mmol / L, 5 mmol / L, 12 mmol / L, and 24 mmol / L.

[0041] For the antigenicity of soy protein isolate, it was measured by indirect competitive ELISA. Compared with untreated soy protein isolate, single ultrasonic modification treatment, and single polyphenol modification treatment, after soy protein isolate was treated with different concentrations of TFA combined with ultrasonic treatment, the antigenicity of the main soy allergenic proteins 7S and 11S decreased significantly. Among them, the antigenicity of soy protein isolate treated with 12 mmol / L TFA combined with ultrasonic treatment was the lowest. Compared with untreated soy protein isolate, the antigenicity of the main soy allergenic protein 7S decreased by 31.41% after treatment with 12 mmol / L TFA alone, and the antigenicity of 11S decreased by 39.14%. After treatment with ultrasonic-polyphenol (12 mmol / L TFA) combination, the antigenicity of the main soy allergenic protein 7S decreased by 78.14%, and the antigenicity of 11S decreased by 68.98%.

[0042] For the solubility and antioxidant properties of soy protein isolate, compared with untreated soy protein isolate, single ultrasonic modification, and single polyphenol modification, after soy protein isolate was treated with different concentrations of TFA combined with ultrasonic treatment, the solubility of soy protein isolate at room temperature increased significantly. Among them, the solubility of soy protein isolate treated with 12 mmol / L TFA combined with ultrasonic treatment was the highest. Specifically, compared with untreated soy protein isolate, its solubility increased by 141.09% at room temperature. Compared with untreated soy protein isolate, the DPPH free radical scavenging rate of soy protein isolate treated with 12 mmol / L TFA combined with ultrasonic treatment increased by 181.02%, and the ABTS free radical scavenging rate increased by 242.54%, and the antioxidant performance was significantly improved.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of a soy protein powder with low allergenicity and high antioxidant property, characterized in that, It includes the following steps: (1) Mix the soy protein powder evenly with pure water, and then perform ultrasonic treatment to obtain an ultrasonically modified soy protein solution; (2) Add the polyphenol solution to the ultrasonically modified soy protein solution obtained in (1), adjust the pH of the solution to alkaline, and stir and react at room temperature to obtain a soy protein solution modified by ultrasound-polyphenol complex; (3) Remove the unbound polyphenols in the soy protein solution obtained in (2), and then perform freeze-drying to obtain an ultrasonically-polyphenol modified soy protein powder.

2. The preparation method according to claim 1, characterized in that, In step (1), the soy protein powder is at least one of soy protein isolate, defatted soybean meal, 7S protein, and 11S protein.

3. The preparation method according to claim 1, wherein In step (1), the soy protein concentration is 4% - 10% w / v.

4. The preparation method according to claim 1, characterized in that, In step (1), the mixed solution is stirred before ultrasonic treatment.

5. The preparation method according to claim 1, wherein In step (1), the ultrasonic treatment is: under the condition of an ice-water bath, treat with an ultrasonic power of 200 - 600 W for 10 - 30 min.

6. The preparation method according to claim 1, wherein, In step (2), the polyphenol is at least one of chlorogenic acid, epigallocatechin gallate, trans-cinnamic acid, and trans-ferulic acid.

7. The preparation method according to claim 1, characterized in that In step (2), the volume of the added polyphenol is the same as the volume of the ultrasonically modified soy protein solution, and the concentration of the added polyphenol is not higher than 24 mmol / L.

8. The preparation method according to claim 1, wherein In step (3), dialysis is used to remove the unbound polyphenols in the soy protein solution obtained in (2). The specific operation of dialysis is: pour the soy protein solution obtained in (2) into a dialysis bag and dialyze at 4°C for 1 - 2 days.

9. A soy protein powder prepared by the method according to any one of claims 1 - 8.

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