Method for improving characteristics of rapeseed protein-quercetin compound through cooperation of polysaccharide and gelation

Abstract

The invention discloses a method for improving the characteristics of a rapeseed protein-quercetin compound through cooperation of polysaccharide and gelation, and belongs to the field of food additive technology development and food safety control. According to the method, a modified rapeseed protein-quercetin compound is used as a raw material, sodium carboxymethyl cellulose and chitosan are used for regulating and controlling the binding process of protein and quercetin, then nano-gelatinization is used for inducing recombination of compound molecules, and the charge polysaccharide nano-nano-gelatinized rapeseed protein-quercetin compound is obtained. The new technology disclosed by the invention not only can effectively reduce the co-dissolution pH value of the protein and the quercetin, but also can improve the functional characteristics of the quercetin solubilizing effect, the oxidation resistance, the emulsifying characteristic and the like of the compound. The method has the characteristics of simplicity in operation and easiness in amplification, and a new resource can be provided for application of the rapeseed protein-polyphenol compound in the field of emulsion food.

Description

Technical Field

[0001] This invention belongs to the field of food additive technology development and food safety control, and specifically relates to a method for improving the functional properties of rapeseed protein-quercetin complex through charge polysaccharide synergistic nanogelation. Background Technology

[0002] The pH-driven method is a common strategy for preparing protein-quercetin complexes. Both quercetin and protein have high solubility in alkaline solutions. Therefore, in the preparation of the complex, the pH of the solution is usually adjusted to alkaline first, and then gradually adjusted to neutral using an acid reagent to induce protein-polyphenol co-assembly. pH 12 is the most commonly used alkaline condition, where the protein and quercetin are completely cosoluble, and the protein peptide chains can fully unfold, providing more quercetin binding sites, which is beneficial for the interaction between the protein and quercetin. However, quercetin is prone to oxidation under strongly alkaline conditions, which not only reduces its antioxidant activity but may also have some potential toxicity. Therefore, it is necessary to lower the cosoluble pH of quercetin and protein.

[0003] Quercetin exhibits high solubility in alkaline solutions (pH 10-12), but protein folding primarily occurs as the pH decreases from 12 to 10, preventing sufficient quercetin binding sites from being exposed on polypeptide chains at pH 10. Slowing down the folding process as the solution pH decreases from 12 to 10 is crucial for successfully lowering the co-solubility pH. pH-driven methods primarily achieve protein folding by gradually weakening electrostatic repulsion through the reduction of negative charges. Therefore, introducing negatively charged substances can enhance intermolecular electrostatic repulsion, making it feasible to slow down protein folding. However, adequate folding of the protein peptide chain is also essential, as it forms a dense barrier to protect quercetin. Therefore, adding positively charged substances to neutralize excess negative charges is necessary during the process of lowering the solution pH to neutral. Sodium carboxymethyl cellulose and chitosan are common charged polysaccharides, carrying negative and positive charges respectively, and are currently widely used in the food industry. Based on this, the present invention fully utilizes the electrostatic effect of sodium carboxymethyl cellulose and chitosan charged polysaccharides to establish a method for regulating protein folding by charged polysaccharides, and combines it with the reassembly of nanogelation thermally induced complex molecules to improve the functional properties of rapeseed protein-quercetin complex, thus proposing this patent. A search revealed no reports on the method and application of charged polysaccharides synergistically nanogelation to improve the functional properties of protein-polyphenol complexes. Summary of the Invention

[0004] The purpose of this invention is to address the safety concerns caused by excessively high co-solubility pH by providing a method for improving the functional properties of rapeseed protein-quercetin complexes through synergistic nanogelation using charged polysaccharides. This method regulates the folding process of protein polypeptide chains using sodium carboxymethyl cellulose and chitosan, and induces molecular reassembly of the complex using nanogelation technology. Ultimately, this reduces the co-solubility pH of modified rapeseed protein and quercetin, thereby improving the complex's functional properties. This technology can serve as a safe method for obtaining highly active rapeseed protein-based emulsifiers, with the aim of further expanding the application of rapeseed protein-quercetin complexes in the food emulsion field.

[0005] To achieve the above-mentioned objective, the method for improving the properties of rapeseed protein-quercetin complex through polysaccharide synergistic gelation of the present invention is carried out according to the following steps:

[0006] (1) Preparation of modified rapeseed protein solution: whey protein, zein and rapeseed protein were mixed in a mass ratio of 1:1:0.2 and prepared into a protein mixed solution with a pH value of 12 using 1 mol / L alkaline solution. The total mass concentration of protein was 2%, and the modified rapeseed protein solution was obtained.

[0007] (2) Anionic polysaccharide regulation: The modified rapeseed protein solution in step (1) was mixed with an aqueous solution of 1.2-2.0 g / L sodium carboxymethyl cellulose at a volume ratio of 1:1, so that sodium carboxymethyl cellulose accounted for 6%-10% of the protein content. The mixture was thoroughly mixed and stirred for 3 hours (pH value stabilized at 12). The pH value of the mixed solution was gradually adjusted to 10 using a 0.1 mol / L citric acid solution. Quercetin was added at a final concentration of 5 g / L and stirred thoroughly for 3 hours (pH value stabilized at 10).

[0008] (3) Cationic polysaccharide regulation: The pH of the solution in step (2) was adjusted from 10 to 7 using a 0.1 mol / L acetic acid solution containing 0.4-1.2 g / L chitosan, so that chitosan accounted for 2%-6% of the protein content, and a rapeseed protein-quercetin complex solution regulated by cationic polysaccharides was obtained.

[0009] (4) Nanogelation: The complex solution in (3) was heat-treated in a water bath at 95°C for 30 min, then cooled rapidly with ice water and stored at 4°C for more than 12 h to complete the nanogelation of the complex. After centrifugation, desalting and freeze-drying, the lyophilized powder of the charge polysaccharide-nanogelated rapeseed protein-quercetin complex was obtained.

[0010] The alkaline solution mentioned in step (1) is a mixture of sodium hydroxide and potassium hydroxide in a 1:1 molar ratio.

[0011] Compared with the prior art, the beneficial effects of the present invention are:

[0012] (1) This invention utilizes charged polysaccharides to regulate the folding process of proteins and quercetin by combining nanogelation, thereby reducing the optimal co-solubility pH value of the two from 12 to 10, which can effectively prevent quercetin from being oxidized and destroyed under strong alkaline conditions.

[0013] (2) The present invention proposes two technologies, charge polysaccharide regulation and nano-gelation, to effectively improve the functional properties of rapeseed protein complex, such as quercetin solubilization, antioxidant properties and emulsification properties, which can broaden the application scope of rapeseed protein and its quercetin complex in the field of emulsion food. Detailed Implementation

[0014] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below.

[0015] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0016] The soluble quercetin content in the complex was calculated according to the method of Chen et al. (Chen, C., Chen, Zhong, Z., Q. Caseinate nanoparticles co-loaded with quercetin and avenanthramide 2 cusing a novel two-step pH-driven method: Formation, characterization, and bioavailability. Food hydrocolloids, 2022, 129: 107669.). The complex solution was centrifuged at 5000g for 30 min, and then the soluble quercetin content was determined using a UV-Vis spectrophotometer at 370 nm.

[0017] The emulsifying properties of the complex were determined according to the method of Liu et al. (Liu, Y., Liu, J., Li, X. et al., Hofmeister anion effects synergize with microbial transglutaminase to enhance the techno-functional properties of pea protein[J]. Food Research International, 2023, 169: 112824.). A 1% complex solution was prepared; 15 mL of the complex solution was mixed with 5 mL of soybean oil, homogenized at 10000 r / min for 2 min, and immediately 20 μL of the emulsion was taken from the bottom of the beaker and mixed with 5 mL of SDS solution. The absorbance was measured at 500 nm and recorded as A0; after the emulsion stood for 30 min, the absorbance was measured again and recorded as A. 30 The Emulsifying Activity Index (EAI) and the Emulsifying Stability Index (ESI) are calculated according to the following formulas:

[0018]

[0019] In the formula, DF is the dilution factor; C is the protein solution concentration (mg / mL); θ is the oil phase volume fraction, 0.25; ΔT = 10 min; ΔA = A0 - A30.

[0020] The antioxidant capacity was determined according to the method of Shao et al. (Shao F, Zhang Y, Wan X. et al., Improving the properties of whey protein isolate-zein nanogels with novelacidifiers: Re-dispersity, stability and quercetin bioavailability. International Journal of Biological Macromolecules, 2024, 266:137567). First, DPPH (0.1 mmol / L, 100 μL) solution and equal volumes of sample solutions of different concentrations were reacted at room temperature in the dark for 30 min. The absorbance was then measured at 517 nm using a microplate reader. The DPPH scavenging capacity was calculated according to the following formula.

[0021] DPPH Scavenging Capacity (%) = (1 - (A2 - A0) / A1) × 100%

[0022] In the formula, A0 is the absorbance of the blank group (without DPPH); A1 is the absorbance of the control group (without sample); and A2 is the absorbance of the test sample group.

[0023] The bioavailability of quercetin in the complex was determined according to the method of Shao et al. (Shao F, Zhang Y, Wan X. et al., Improving the properties of whey protein isolate-zein nanogels with novel acidifiers: Re-dispersity, stability and quercetin bioavailability. International Journal of Biological Macromolecules, 2024, 266:137567).

[0024] Example 1

[0025] Whey protein, zein, and rapeseed protein were mixed in a mass ratio of 1:1:0.2. A protein mixture solution with a pH of 12 was prepared using a 1 mol / L alkaline solution (sodium hydroxide and potassium hydroxide mixed in a 1:1 molar ratio), resulting in a total protein concentration of 2%. This mixture was then mixed with a 1.2 g / L sodium carboxymethyl cellulose aqueous solution at a volume ratio of 1:1, ensuring that sodium carboxymethyl cellulose comprised 6% of the protein mass. The mixture was thoroughly mixed and stirred for 3 hours (until the pH stabilized at 12). Finally, the pH of the mixture was gradually adjusted using a 0.1 mol / L citric acid solution. To a final concentration of 5 g / L, quercetin was added and stirred thoroughly for 3 hours (until the pH stabilized at 10). The pH was then adjusted from 10 to 7 using a 0.1 mol / L acetic acid solution containing 0.8 g / L chitosan, ensuring that chitosan comprised 4% of the protein mass, thus obtaining a rapeseed protein-quercetin complex solution regulated by charge polysaccharides. This solution was then heat-treated in a 95°C water bath for 30 minutes and stored at 4°C for 12 hours to complete the nanogelation of the complex. After centrifugation, desalting, and freeze-drying, a freeze-dried powder of the charge polysaccharide-nanogelated rapeseed protein-quercetin complex was obtained. The effect of 6% sodium carboxymethyl cellulose and 4% chitosan synergistic nanogelation on the functional properties of the complex was evaluated.

[0026] Example 2

[0027] The procedure was the same as in Example 1, except that a protein mixture at pH 12 was mixed with a 1.6 g / L sodium carboxymethyl cellulose aqueous solution at a volume ratio of 1:1, so that sodium carboxymethyl cellulose accounted for 8% of the protein mass. The pH was adjusted from 10 to 7 using a 0.1 mol / L acetic acid solution containing 0.4 g / L chitosan, so that chitosan accounted for 2% of the protein mass. The effect of synergistic nanogelation of 8% sodium carboxymethyl cellulose and 2% chitosan on the functional properties of the complex was evaluated.

[0028] Example 3

[0029] The procedure was the same as in Example 1, except that a protein mixture at pH 12 was mixed with a 1.6 g / L sodium carboxymethyl cellulose aqueous solution at a volume ratio of 1:1, so that sodium carboxymethyl cellulose accounted for 8% of the protein mass. Then, the pH was adjusted from 10 to 7 using a 0.1 mol / L acetic acid solution containing 0.8 g / L chitosan, so that chitosan accounted for 4% of the protein mass. The effect of synergistic nanogelation of 8% sodium carboxymethyl cellulose and 4% chitosan on the functional properties of the complex was evaluated.

[0030] Example 4

[0031] The procedure was the same as in Example 1, except that a protein mixture at pH 12 was mixed with an aqueous solution of sodium carboxymethyl cellulose (1.6 g / L) at a volume ratio of 1:1, so that sodium carboxymethyl cellulose accounted for 8% of the protein mass. Then, the pH was adjusted from 10 to 7 using a 0.1 mol / L acetic acid solution containing 1.2 g / L chitosan, so that chitosan accounted for 6% of the protein mass. The effect of synergistic nanogelation of 8% sodium carboxymethyl cellulose and 6% chitosan on the functional properties of the complex was evaluated.

[0032] Example 5

[0033] The procedure was the same as in Example 1, except that a protein mixture at pH 12 was mixed with an aqueous solution of sodium carboxymethyl cellulose (2.0 g / L) at a volume ratio of 1:1, so that sodium carboxymethyl cellulose accounted for 10% of the protein mass. The pH was then adjusted from 10 to 7 using a 0.1 mol / L acetic acid solution containing 0.8 g / L chitosan, so that chitosan accounted for 4% of the protein mass. The effect of synergistic nanogelation of 10% sodium carboxymethyl cellulose and 4% chitosan on the functional properties of the complex was evaluated.

[0034] Comparative Example 1

[0035] Whey protein, zein, and rapeseed protein were mixed in a mass ratio of 1:1:0.2 to prepare a deionized aqueous solution with a total protein mass concentration of 2%. The pH of the mixed solution was adjusted to 12 using a 1 mol / L alkaline solution (sodium hydroxide and potassium hydroxide were mixed in a 1:1 molar ratio), and the mixture was stirred thoroughly for 3 hours (maintaining the system pH 12). Quercetin was added to a final concentration of 5 g / L, and the mixture was stirred thoroughly for 3 hours. The pH of the mixed solution was then adjusted to 7 using a 0.1 mol / L acetic acid solution. After centrifugation, desalting, and freeze-drying, a rapeseed protein-quercetin complex driven by pH 12-7 was obtained.

[0036] Comparative Example 2

[0037] The procedure was the same as in Comparative Example 1, except that the pH of the mixed solution was adjusted to 12 using a 1 mol / L alkaline solution and stirred thoroughly for 3 hours (maintaining the system pH at 12); then the pH of the mixed solution was adjusted to 10 using 0.1 mol / L citric acid, followed by the addition of quercetin at a final concentration of 5 g / L and stirring thoroughly for 3 hours; finally, the pH of the mixed solution was adjusted to 7 using a 0.1 mol / L acetic acid solution. The remaining steps were the same as in Comparative Example 1, resulting in a rapeseed protein-quercetin complex driven by pH 12-10-7.

[0038] Comparative Example 3

[0039] Except for the absence of nanogelation, the remaining steps are the same as in Example 3.

[0040] Table 1. Effects of charge-polysaccharide-regulated synergistic nanogelation on the water solubility of quercetin in modified rapeseed protein-quercetin complex.

[0041]

[0042] Note: Different letters in the same column represent significant differences (p<0.05).

[0043] Table 1. Effect of charge polysaccharide-regulated synergistic nanogelation on the water solubility of quercetin in rapeseed protein-quercetin complex.

[0044] Quercetin is a flavonoid compound widely found in plants, possessing various physiological activities such as antioxidant, anti-inflammatory, cardiovascular protection, and immune regulation. It was recognized as a safe food ingredient by the FAD International organization in 2010. However, its low water solubility limits its physiological activities, hindering its application in the food industry. Therefore, increasing the soluble quercetin content in the complex is essential. As shown in Table 1, the examples demonstrate that different mass percentages of sodium carboxymethyl cellulose and chitosan have varying effects on the soluble quercetin content in the rapeseed protein-quercetin complex. Example 3 showed the highest soluble quercetin content, with sodium carboxymethyl cellulose and chitosan comprising 8% and 4% of the mass, respectively. The soluble quercetin content (0.62 mg / mL) was significantly higher than that of Comparative Example 3 (0.29 mg / mL), and the soluble quercetin content was increased by 34.8%, 100.0%, and 113.8% compared with Comparative Examples 1, 2, and 3, respectively. The soluble quercetin content in Comparative Example 1 (0.46 mg / mL) was significantly higher than that in Comparative Example 2 (0.31 mg / mL), indicating that a lower co-solubility pH (10) would reduce the water solubility of quercetin in the complex, which is not conducive to the exertion of its physiological activity; however, after synergistic treatment with charged polysaccharides and nanogelation, the soluble quercetin content in the complex could be significantly increased, indicating that nanogelation can significantly improve the water solubility of quercetin in the complex by charged polysaccharides. More importantly, the content of soluble quercetin in Example 3 was significantly higher than that in Comparative Example 1, indicating that the synergistic nanogelation treatment with charged polysaccharides not only solves the adverse effects of decreased co-solution pH, but also further improves the solubilizing effect of the complex on quercetin. In conclusion, synergistic nanogelation with charged polysaccharides can effectively increase the content of soluble quercetin in the complex.

[0045] Table 2. Effects of charge-polysaccharide-regulated synergistic nanogelation on the physicochemical properties of rapeseed protein-quercetin composites.

[0046] Example 3, which showed the best solubilizing effect of quercetin, was selected as the research object, and Comparative Examples 1 and 3 were used as control groups to analyze the effect of charge polysaccharide-regulated synergistic nanogelation on the physicochemical properties of rapeseed protein-quercetin composites. As shown in Table 2, the particle size of Comparative Example 3 was significantly higher than that of Comparative Example 1 (p<0.05), indicating that charge polysaccharide regulation can significantly increase the particle size of the composite. However, the particle size of Example 3 was significantly lower than that of Comparative Example 3 (p<0.05), indicating that nanogelation can effectively reduce the particle size of the composite. Furthermore, the number of surface negative charges in Example 3 was not significantly different from that in Comparative Examples 1 and 3 (p>0.05). This indicates that charge polysaccharide-regulated synergistic nanogelation did not change the surface charge of the composite. This suggests that the chitosan addition ratio is scientifically reasonable and can effectively neutralize the negative charge brought by the addition of anionic polysaccharides. Polydispersion results showed that all three products could form homogeneous aqueous solutions. However, the transmittance of the solution in Example 3 was significantly higher than that in Comparative Examples 1 and 3, indicating that the combined treatment of charge polysaccharide-regulated synergistic nanogelation significantly improved the dispersibility of the composite. The surface hydrophobicity of Example 3 was significantly higher than that of Comparative Examples 1 and 3 (p<0.05), and surface hydrophobicity is closely related to the functional properties of the complex.

[0047] Table 2. Effects of charge-polysaccharide-regulated synergistic nanogelation on the physicochemical properties of modified rapeseed protein-quercetin composites.

[0048] product Particle size Potential polydispersity index Light transmittance Surface hydrophobicity Comparative Example 1 181.53±3.17c -62.75±3.19ab 0.23±0.01c 43.46±0.76c 910.87±4.92c Comparative Example 3 265.44±6.78a -61.36±2.33b 0.29±0.02a 57.00±0.26b 1401.80±6.89b Example 3 223.82±6.68b -66.46±2.74a 0.25±0.01b 61.13±0.16a 2241.90±18.55a

[0049] Note: Different letters in the same column represent significant differences (p<0.05).

[0050] Table 3 shows the effect of charge polysaccharide-regulated synergistic nanogelation on the functional properties of rapeseed protein-quercetin complex.

[0051] Demulsification and rancidity are the main forms of degradation in emulsion products. The former is mainly related to the emulsifying properties of the emulsifier, while the latter is mainly related to the oxidation of oils. Therefore, improving the emulsifying properties and antioxidant properties of the complex can effectively promote its application in the emulsion field. The emulsifying activity index and emulsifying stability index of Example 3 were significantly higher than those of Comparative Example 1 and Comparative Example 3 (both p < 0.05). In particular, the emulsifying stability index of Example 3 was increased by 181.54% and 79.66% compared with Comparative Example 1 and 3, respectively, indicating that the synergistic nanogelation of charged polysaccharides can effectively improve the emulsifying stability of the complex, slow down the demulsification process of the emulsion, and thus extend its shelf life. In addition, the in vitro DPPH· scavenging ability of Example 3 was also significantly higher than that of Comparative Example 1 and 3 (both p < 0.05), increasing by 281.54% and 72.37% respectively, indicating that the synergistic nanogelation of charged polysaccharides can effectively improve the antioxidant properties of the complex and effectively slow down the oxidative rancidity of oils in the emulsion. Furthermore, the synergistic nanogelation of charged polysaccharides can significantly improve the bioavailability of quercetin in the complex.

[0052] Table 3. Effects of charge-polysaccharide-regulated synergistic nanogelation on the functional properties of modified rapeseed protein-quercetin complex.

[0053] product Emulsifying activity index Emulsion stability index DPPH clearance rate (%) Bioavailability Comparative Example 1 175.27±1.33c 17.18±1.26c 26.38±2.17c 7.34±0.13b Comparative Example 3 186.27±2.17b 65.24±2.17b 41.34±3.27b 6.62±0.21c Example 3 197.22±2.24a 81.28±1.28a 74.27±4.27a 8.85±0.12a

[0054] Note: Different letters in the same column represent significant differences (p<0.05).

[0055] The mechanism by which charged polysaccharides synergistically regulate rapeseed protein-quercetin functional properties through nanogelation. During pH regulation, the net charge carried by the protein polypeptide chains gradually decreases, leading to a reduction in electrostatic repulsion and eventual folding under hydrophobic forces. Sodium carboxymethyl cellulose, a common anionic polysaccharide, can increase the net charge of the complex protein, thereby increasing the resistance to polypeptide chain folding by enhancing the electrostatic repulsion and inhibiting the folding of the complex rapeseed protein. This allows the structure of the complex rapeseed protein to remain relatively open at pH 10, exposing more quercetin binding sites. Under these conditions, the added quercetin can still enter the complex and bind to the active groups on the protein polypeptide chains. However, the protein folding process forces the active groups of the protein polypeptide chains to come into close contact with quercetin, which is beneficial for the interaction between the complex rapeseed protein and quercetin. Chitosan, a cationic polysaccharide, can carry a large amount of positive charge, effectively neutralizing excessive negative charge to reduce the electrostatic repulsion of the polypeptide chains in the complex and accelerate the protein folding process. To address this, this patent incorporates chitosan to reduce electrostatic repulsion between polypeptide chains, accelerating the folding process of the composite rapeseed protein. It is worth noting that protein polypeptide chains are flexible structures, while polysaccharides are mostly rigid structures; the two exhibit some incompatibility within the composite, preventing the formation of a compact molecular structure. To further improve the molecular structure of the composite, we utilize a wet-heat method to nanogel the composite's aqueous solution. High temperatures provide energy for molecular recombination between the protein polypeptide chains and polysaccharides, thereby improving the composite's molecular structure and ultimately achieving the goal of lowering the co-solubility pH and improving the composite's functional properties.

[0056] The invention has been described through embodiments that are currently considered to be the most preferred and practical. It should be understood that the invention is not limited to the disclosed embodiments. Rather, its purpose is to cover various modifications and equivalent arrangements within the spirit and scope of the appended claims, the scope of which is to be interpreted in the broadest possible sense to include all such modifications and equivalent structures permitted under the law.

Claims

1. A method for improving the properties of rapeseed protein-quercetin complex through polysaccharide synergistic gelation, characterized in that... Follow these steps: (1) Preparation of modified rapeseed protein solution: whey protein, zein and rapeseed protein were mixed in proportion and prepared into a protein mixture solution with pH value of 12 using 1 mol / L alkaline solution. The total mass concentration of protein was 2%, and the modified rapeseed protein solution was obtained. (2) Anionic polysaccharide regulation: The modified rapeseed protein solution in step (1) was mixed with the aqueous solution of sodium carboxymethyl cellulose at a volume ratio of 1:1, and stirred for 3 hours (pH value stabilized at 12); the pH value of the mixed solution was gradually adjusted to 10 using 0.1 mol / L citric acid solution, and quercetin with a final concentration of 5 g / L was added, and stirred for 3 hours (pH value stabilized at 10); (3) Cationic polysaccharide regulation: The pH of the solution in step (2) was adjusted from 10 to 7 using a 0.1 mol / L acetic acid solution containing chitosan to obtain a rapeseed protein-quercetin complex solution regulated by cationic polysaccharides. (4) Nanogelation: The complex solution in (3) was heat-treated in a water bath at 95°C for 30 min, then cooled rapidly with ice water and stored at 4°C for more than 12 h to complete the nanogelation of the complex. After centrifugation, desalting and freeze-drying, the lyophilized powder of the charge polysaccharide-nanogelated rapeseed protein-quercetin complex was obtained.

2. The method for improving the properties of rapeseed protein-quercetin complex through polysaccharide synergistic gelation according to claim 1, characterized in that... The alkaline solution mentioned in step (1) is a mixture of sodium hydroxide and potassium hydroxide in a 1:1 molar ratio.

3. The method for improving the properties of rapeseed protein-quercetin complex through polysaccharide synergistic gelation according to claim 1, characterized in that... In the preparation of the rapeseed protein mixed solution in step (1), whey protein, zein and rapeseed protein are in a mass ratio of 1:1:0.

2.

4. The method for improving the properties of rapeseed protein-quercetin complex by polysaccharide synergistic gelation according to claim 1, characterized in that... In step (2), the concentration of sodium carboxymethyl cellulose is 1.2-2.0 g / L, and the addition ratio accounts for 6%-10% of the protein content.

5. The method for improving the properties of rapeseed protein-quercetin complex by polysaccharide synergistic gelation according to claim 1, characterized in that... In step (3), the chitosan concentration is 0.4-1.2 g / L, and the addition ratio accounts for 2%-6% of the protein mass.

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