Sodium carboxymethyl cellulose / soybean protein isolate / sericin / anthocyanin composite membrane material and method

Abstract

The sodium carboxymethyl cellulose / soybean protein isolate / sericin protein / anthocyanin composite membrane material comprises sodium carboxymethyl cellulose / anthocyanin dispersion liquid, soybean protein isolate / sericin protein dispersion liquid and sodium carboxymethyl cellulose / anthocyanin / soybean protein isolate / sericin protein dispersion liquid, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide are used as cross-linking agents to activate sodium carboxymethyl cellulose, and carboxyl of the sodium carboxymethyl cellulose is chemically cross-linked with amino of soybean protein isolate and amino of sericin; hydrogen bonds and electrostatic interaction are formed by hydroxyl groups of anthocyanin and amino groups of soybean protein isolate and sericin; the composite membrane material is prepared after natural drying at room temperature, and has good tensile property, antibacterial property and pH responsiveness; the prepared composite membrane material has excellent tensile capacity; the adopted raw materials are low in cost and easy to obtain; the preparation process is simple and easy to operate; the composite membrane material has the characteristics of greenness and environmental protection, and is wide in application range.

Description

Technical Field

[0001] The present invention belongs to the technical field of natural polymer materials, and particularly relates to a sodium carboxymethyl cellulose / soybean protein isolate / sericin / anthocyanin composite film material and method. Background Art

[0002] Food packaging plays a crucial role in ensuring the safety and preservation of perishable products. Traditional plastic packaging is usually non-biodegradable and can cause serious environmental problems, including plastic pollution, microplastic pollution, and the use of toxic chemicals in the production process. This highlights the urgent need for biodegradable and sustainable packaging solutions. In addition to sustainability, smart packaging technologies aim to extend the shelf life or monitor food quality by responding to internal environmental changes. For example, smart packaging that detects spoilage by changes in pH caused by volatile basic nitrogen (VB-N) compounds (such as ammonia and trimethylamine produced during the decomposition of seafood) has attracted great interest. Summary of the Invention

[0003] To overcome the deficiencies of the above prior art, the purpose of the present invention is to provide a sodium carboxymethyl cellulose / soybean protein isolate / sericin / anthocyanin composite film material and method, which have the characteristics of being green, safe, environmentally friendly, and biodegradable.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: The sodium carboxymethyl cellulose / soybean protein isolate / sericin / anthocyanin composite film material, calculated according to the following weight ratio, is characterized by including the following components: 10 - 20 g of sodium carboxymethyl cellulose / anthocyanin dispersion, 20 - 30 g of soybean protein isolate / sericin dispersion, and 30 - 50 g of sodium carboxymethyl cellulose / anthocyanin / soybean protein isolate / sericin dispersion.

[0005] The preparation method of the sodium carboxymethyl cellulose / anthocyanin dispersion includes the following steps: Put 0.8 - 1 g of sodium carboxymethyl cellulose, 800 - 2000 g of water, and 0.72 - 0.9 g of anthocyanin into a round-bottom flask, adjust the stirring speed to 200 - 300 r / min, stir at 40 - 50 °C until completely dissolved, add 0.4 - 0.5 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.2 - 0.25 g of N-hydroxysuccinimide, and continue to stir at 40 - 50 °C for 0.5 - 1 h to obtain the sodium carboxymethyl cellulose / anthocyanin dispersion.

[0006] The preparation method of the soybean protein isolate / sericin dispersion includes the following steps: Add 0.5 - 1 g of soy protein isolate and 0.5 - 2 g of sericin protein to a round-bottom flask, add water, adjust the temperature to 60 - 70 °C, adjust the stirring speed to 250 - 350 r / min, stir and mix the soy protein isolate and sericin protein solution evenly to obtain a soy protein isolate / sericin protein dispersion.

[0007] The mass ratio of the sodium carboxymethylcellulose to water is 1:10 - 20; The mass ratio of the sodium carboxymethylcellulose to anthocyanin is: 1:0.9; The activation time is: 1 h; The mass ratio of the soy protein isolate to water is 1:40 - 60; The mass ratio of the sericin protein to water is 1:15 - 40; The mass ratio of the soy protein isolate to sericin protein is 1:1 - 4; The stirring time is 30 - 40 min.

[0008] For the sodium carboxymethylcellulose / anthocyanin / soy protein isolate / sericin protein dispersion, its preparation method includes the following steps: Place 10 - 20 g of sodium carboxymethylcellulose / anthocyanin dispersion in a round-bottom flask, and use a constant-pressure dropping funnel to drop 20 - 30 g of soy protein isolate / sericin protein dispersion for polymerization reaction under stirring. The reaction temperature is 60 - 70 °C, and the reaction time is 60 - 90 min to obtain the sodium carboxymethylcellulose / anthocyanin / soy protein isolate / sericin protein dispersion.

[0009] The mass ratio of the sodium carboxymethylcellulose to soy protein isolate is: 1:0.5; The mass ratio of the sodium carboxymethylcellulose to sericin protein is: 1:0.5 - 2; For the stirring, its speed is 200 - 300 r / min.

[0010] The preparation method of the composite membrane material includes the following steps: Add glycerol accounting for 20% - 40% of the solid content in the sodium carboxymethylcellulose / anthocyanin / soy protein isolate / sericin protein dispersion to the flask and stir for reaction. Pour the reacted liquid into a film-forming plate and let it stand at room temperature to dry and form a film, thus obtaining the sodium carboxymethylcellulose / soy protein isolate / sericin protein / anthocyanin composite membrane material.

[0011] The mass ratio of the solid content in the sodium carboxymethylcellulose / anthocyanin / soy protein isolate / sericin protein dispersion to glycerol is 1:0.2 - 0.4; For the stirring reaction described above, the stirring speed is 200 - 300 r / min; For the stirring reaction described above, the time is 60 - 90 min; For the reaction temperature described above, the temperature is 60 - 70 °C.

[0012] The beneficial effects of the present invention are as follows: The present invention uses green, renewable, and biodegradable natural polymer materials - sodium carboxymethylcellulose, anthocyanin, soy protein isolate, and sericin as raw materials; according to the biocompatibility and biodegradability of soy protein isolate, the good film-forming property of sodium carboxymethylcellulose, the antibacterial property of sericin; the antioxidant property and pH indicator function of anthocyanin, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide are used as cross-linking agents to activate sodium carboxymethylcellulose, improve the accessibility of the reaction, and enhance the reaction activity of the carboxyl and aldehyde groups of sodium carboxymethylcellulose; then, chemical cross-linking and intermolecular hydrogen bonding and van der Waals forces are used to achieve the cross-linking and assembly of sodium carboxymethylcellulose, anthocyanin, soy protein isolate, and sericin, and a highly stable sodium carboxymethylcellulose / soy protein isolate / sericin / anthocyanin composite film material with pH-responsive characteristics is developed. After natural drying at room temperature, the composite film material is obtained, which has the following advantages: 1) Improve the film-forming property and reactivity of sodium carboxymethylcellulose; 2) Improve the structural uniformity and tensile strength of the composite film material, and its tensile strength reaches 52.15 Mpa, which is 70.48% higher than that of the pure sodium carboxymethylcellulose film; 3) Improve the ultraviolet absorption resistance of the composite film, and the anti-uv absorption at 200 - 350 nm can reach more than 90%; 4) Sericin has good antibacterial properties, and anthocyanin as a pH-responsive indicator provides a green, non-toxic, antibacterial, and pH-responsive biomass composite film material; 5) Provide a low-cost and environmentally friendly biomass composite film material.

[0013] The present invention has good tensile properties, antibacterial properties, and pH responsiveness; effectively utilizes biological environmental resources such as sodium carboxymethylcellulose, anthocyanin, soy protein, and sericin, and the prepared composite film material has excellent tensile ability and is suitable for the field of food preservation; the raw materials used in the present invention are low-cost and easy to obtain; the preparation process is simple and easy to operate; the prepared composite film material has both green and environmental protection characteristics and a wide range of applications. Specific Embodiments

[0014] The present invention will be further described in detail below with reference to specific embodiments. Embodiment

[0015] Sodium carboxymethyl cellulose / soybean protein isolate / sericin / anthocyanin composite film material, calculated according to the following weight ratio, includes the following components: 10 g of sodium carboxymethyl cellulose / anthocyanin dispersion, 20 g of soybean protein / sericin dispersion, 30 g of sodium carboxymethyl cellulose / anthocyanin / soybean protein isolate / sericin dispersion; The preparation method of the described sodium carboxymethyl cellulose / anthocyanin dispersion includes the following steps: Put 1 g of sodium carboxymethyl cellulose, 1000 g of water, and 0.9 g of anthocyanin into a round-bottom flask, adjust the stirring speed to 200 r / min, stir at 40 °C until completely dissolved, add 0.5 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.25 g of N-hydroxysuccinimide, and continue to stir at 40 °C for 1 h to obtain sodium carboxymethyl cellulose / anthocyanin dispersion.

[0016] The preparation method of the described soybean protein isolate / sericin dispersion includes the following steps: Put 0.5 g of soybean protein isolate and 0.5 g of sericin into a round-bottom flask with water, adjust the temperature to 60 °C, adjust the stirring speed to 250 r / min, and stir and mix the soybean protein isolate and sericin solutions evenly to obtain soybean protein isolate / sericin dispersion.

[0017] The mass ratio of the described sodium carboxymethyl cellulose to water is 1:10; The mass ratio of the described sodium carboxymethyl cellulose to anthocyanin is: 1:0.9; The mass ratio of the described soybean protein isolate to water is 1:50; The mass ratio of the described sericin to water is 1:40; The mass ratio of the described soybean protein isolate to sericin is 1:1; The described reaction time is 30 min.

[0018] The preparation method of the described sodium carboxymethyl cellulose / anthocyanin / soybean protein isolate / sericin dispersion includes the following steps: Put 10 g of sodium carboxymethyl cellulose / anthocyanin dispersion into a round-bottom flask, and use a constant-pressure dropping funnel to drop 20 g of soybean protein isolate / sericin dispersion for polymerization reaction under stirring. The reaction temperature is 60 °C, and the reaction time is 90 min to obtain sodium carboxymethyl cellulose / anthocyanin / soybean protein isolate / sericin dispersion.

[0019] The mass ratio of the described sodium carboxymethyl cellulose to soybean protein isolate is: 1:0.5; The mass ratio of the described sodium carboxymethyl cellulose to sericin is: 1:0.5; The stirring speed is 200 r / min.

[0020] Add the sodium carboxymethylcellulose / anthocyanin / soybean protein isolate / sericin protein dispersion and glycerol accounting for 20% of the solid content in the sodium carboxymethylcellulose / anthocyanin / soybean protein isolate / sericin protein dispersion into a flask for stirring reaction. Pour the liquid after the reaction into a film-forming plate, and let it stand at room temperature for drying to form a film, thus obtaining the sodium carboxymethylcellulose / soybean protein isolate / sericin protein / anthocyanin composite film material.

[0021] The mass ratio of the solid content in the sodium carboxymethylcellulose / anthocyanin / soybean protein isolate / sericin protein dispersion is 1:0.2; The stirring speed of the comparative document is 200 r / min; The reaction time is 60 min; The reaction temperature is 60 °C. Example

[0022] The sodium carboxymethylcellulose / soybean protein isolate / sericin protein / anthocyanin composite film material, by mass fraction, includes the following components: 10 g of sodium carboxymethylcellulose / anthocyanin dispersion, 20 g of soy protein / sericin protein dispersion, 30 g of sodium carboxymethylcellulose / anthocyanin / soybean protein isolate / sericin protein dispersion; The preparation method of the sodium carboxymethylcellulose / anthocyanin dispersion includes the following steps: Put 1 g of sodium carboxymethylcellulose, 1000 g of water, and 0.9 g of anthocyanin accounting for the mass of sodium carboxymethylcellulose into a round-bottom flask, adjust the stirring speed to 250 r / min, stir at 45 °C until completely dissolved, add 0.5 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.25 g of N-hydroxysuccinimide, and continue to stir at 45 °C for 0.8 h to obtain the sodium carboxymethylcellulose / anthocyanin dispersion.

[0023] The preparation method of the soy protein isolate / sericin protein dispersion includes the following steps: Put 0.8 g of soy protein isolate and 1.3 g of sericin protein and water into a round-bottom flask, adjust the temperature to 65 °C, adjust the stirring speed to 300 r / min, and stir and mix the soy protein isolate and sericin protein solutions evenly to obtain the soy protein isolate / sericin protein dispersion.

[0024] The mass ratio of sodium carboxymethylcellulose to water is 1:15; The mass ratio of sodium carboxymethylcellulose to anthocyanin is: 1:0.9; The activation time is: 1 h; The mass ratio of the soy protein isolate to water is 1:50; The mass ratio of the sericin protein to water is 1:28; The mass ratio of the soy protein isolate to the sericin protein is 1:2; The reaction time is 35 min.

[0025] For the carboxymethyl cellulose sodium / anthocyanin / soy protein isolate / sericin protein dispersion, its preparation method comprises the following steps: Place 15 g of the carboxymethyl cellulose sodium / anthocyanin dispersion in a round-bottom flask, and while stirring, use a constant-pressure dropping funnel to drop the soy protein isolate / sericin protein dispersion for polymerization reaction. The reaction temperature is 65 °C and the reaction time is 75 min to obtain the carboxymethyl cellulose sodium / anthocyanin / soy protein isolate / sericin protein dispersion.

[0026] The mass ratio of the carboxymethyl cellulose sodium to the soy protein isolate is: 1:0.5; The mass ratio of the carboxymethyl cellulose sodium to the sericin protein is: 1:1.3; For the stirring, its speed is 250 r / min.

[0027] Add the carboxymethyl cellulose sodium / anthocyanin / soy protein isolate / sericin protein dispersion and glycerol accounting for 30% of the solid content in the carboxymethyl cellulose sodium / anthocyanin / soy protein isolate / sericin protein dispersion into the flask for stirring reaction. Pour the liquid after the reaction is completed into a film-forming plate and let it stand at room temperature for drying to form a film, thus obtaining the carboxymethyl cellulose sodium / soy protein isolate / sericin protein / anthocyanin composite film material.

[0028] The mass ratio of the solid content in the carboxymethyl cellulose sodium / anthocyanin / soy protein isolate / sericin protein dispersion to the glycerol is 1:0.3; The stirring speed is 250 r / min; For the reaction, the time is 75 min; For the reaction temperature, the temperature is 65 °C. Example

[0029] The carboxymethyl cellulose sodium / soy protein isolate / sericin protein / anthocyanin composite film material, by mass fraction, is characterized by comprising the following components: 10 g of the carboxymethyl cellulose sodium / anthocyanin dispersion, 30 g of the soy protein / sericin protein dispersion, and 40 g of the carboxymethyl cellulose sodium / anthocyanin / soy protein isolate / sericin protein dispersion; For the carboxymethyl cellulose sodium / anthocyanin dispersion, its preparation method comprises the following steps: Put 1 g of sodium carboxymethylcellulose, 1000 g of water, and 0.9 g of anthocyanin into a round-bottom flask. Adjust the stirring speed to 300 r / min and stir at 50 °C until completely dissolved. Add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, which account for 50% and 25% of the mass of sodium carboxymethylcellulose respectively, and continue to stir at 50 °C for 0.5 h to obtain a sodium carboxymethylcellulose / anthocyanin dispersion.

[0030] The preparation method of the soy protein isolate / sericin dispersion described above includes the following steps: Put 1 g of soy protein isolate and 2 g of sericin into a round-bottom flask with water. Adjust the temperature to 70 °C and the stirring speed to 350 r / min. Stir and mix the soy protein isolate and sericin solutions evenly to obtain a soy protein isolate / sericin dispersion.

[0031] The mass ratio of the sodium carboxymethylcellulose to water is 1:20; The mass ratio of the sodium carboxymethylcellulose to anthocyanin is 1:0.9; The activation time is 1 h; The mass ratio of the soy protein isolate to water is 1:60; The mass ratio of the sericin to water is 1:15; The mass ratio of the soy protein isolate to sericin is 1:4; The reaction time is 40 min.

[0032] The preparation method of the sodium carboxymethylcellulose / anthocyanin / soy protein isolate / sericin dispersion described above includes the following steps: Put 20 g of the sodium carboxymethylcellulose / anthocyanin dispersion into a round-bottom flask. While stirring, use a constant-pressure dropping funnel to drop the soy protein isolate / sericin dispersion for polymerization reaction. The reaction temperature is 70 °C and the reaction time is 60 min to obtain a sodium carboxymethylcellulose / anthocyanin / soy protein isolate / sericin dispersion.

[0033] The mass ratio of the sodium carboxymethylcellulose to the soy protein isolate is 1:0.5; The mass ratio of the sodium carboxymethylcellulose to sericin is 1:2; For the stirring described above, the speed is 300 r / min.

[0034] Add the sodium carboxymethylcellulose / anthocyanin / soy protein isolate / sericin protein dispersion and glycerol accounting for 40% of the solid content in the sodium carboxymethylcellulose / anthocyanin / soy protein isolate / sericin protein dispersion into a flask, stir and react, pour the liquid after the reaction is completed into a film-forming plate, and let it stand at room temperature to dry and form a film, thus obtaining the sodium carboxymethylcellulose / soy protein isolate / sericin protein / anthocyanin composite film material.

[0035] The mass ratio of the solid content to glycerol in the sodium carboxymethylcellulose / anthocyanin / soy protein isolate / sericin protein dispersion is 1:0.4; The stirring speed is 300 r / min; The reaction time is 90 min; The reaction temperature is 70 °C. Example

[0036] The sodium carboxymethylcellulose / soy protein isolate / sericin protein / anthocyanin composite film material, calculated according to the following weight ratio, is characterized by comprising the following components: 15 g of sodium carboxymethylcellulose / anthocyanin dispersion, 25 g of soy protein isolate / sericin protein dispersion, and 50 g of sodium carboxymethylcellulose / anthocyanin / soy protein isolate / sericin protein dispersion; The preparation method of the sodium carboxymethylcellulose / anthocyanin dispersion comprises the following steps: Put 0.8 g of sodium carboxymethylcellulose, 800 g of water, and 0.72 g of anthocyanin into a round-bottom flask, adjust the stirring speed to 200 r / min, stir at 40 °C until completely dissolved, add 0.4 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.2 g of N-hydroxysuccinimide, and continue to stir and react at 40 °C for 1 h to obtain the sodium carboxymethylcellulose / anthocyanin dispersion; The preparation method of the soy protein isolate / sericin protein dispersion comprises the following steps: Put 0.5 g of soy protein isolate and 0.5 g of sericin protein and water into a round-bottom flask, adjust the temperature to 60 °C, adjust the stirring speed to 250 r / min, and stir and mix the soy protein isolate and sericin protein solutions evenly to obtain the soy protein isolate / sericin protein dispersion.

[0037] The stirring time is 40 min.

[0038] The preparation method of the sodium carboxymethylcellulose / anthocyanin / soy protein isolate / sericin protein dispersion comprises the following steps: Place 20 g of sodium carboxymethyl cellulose / anthocyanin dispersion in a round-bottom flask. While stirring, add 25 g of soy protein isolate / sericin protein dispersion dropwise through a constant-pressure dropping funnel for polymerization reaction. The reaction temperature is 70 °C and the reaction time is 60 min to obtain sodium carboxymethyl cellulose / anthocyanin / soy protein isolate / sericin protein dispersion.

[0039] For the said stirring, the speed is 300 r / min.

[0040] The preparation method of the composite film material includes the following steps: Add glycerol accounting for 40% of the solid content in the sodium carboxymethyl cellulose / anthocyanin / soy protein isolate / sericin protein dispersion to the flask containing the sodium carboxymethyl cellulose / anthocyanin / soy protein isolate / sericin protein dispersion and stir for reaction. Pour the liquid after the reaction is completed into a film-forming plate and let it stand at room temperature for drying to form a film, thus obtaining the sodium carboxymethyl cellulose / soy protein isolate / sericin protein / anthocyanin composite film material.

[0041] The mass ratio of the solid content in the sodium carboxymethyl cellulose / anthocyanin / soy protein isolate / sericin protein dispersion to glycerol is 1:0.2 - 0.4; For the said stirring reaction, the stirring speed is 300 r / min; For the said stirring reaction, the time is 90 min; For the said reaction temperature, the temperature is 70 °C. Example

[0042] The sodium carboxymethyl cellulose / soy protein isolate / sericin protein / anthocyanin composite film material, according to the following weight ratio, is characterized by including the following components: 20 g of sodium carboxymethyl cellulose / anthocyanin dispersion, 30 g of soy protein isolate / sericin protein dispersion, 40 g of sodium carboxymethyl cellulose / anthocyanin / soy protein isolate / sericin protein dispersion.

[0043] The preparation method of the said sodium carboxymethyl cellulose / anthocyanin dispersion includes the following steps: Put 0.9 g of sodium carboxymethyl cellulose, 2000 g of water, and 0.79 g of anthocyanin in a round-bottom flask. Adjust the stirring speed to 250 r / min and stir at 50 °C until completely dissolved. Add 0.45 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.23 g of N-hydroxysuccinimide, and continue to stir and react at 45 °C for 0.8 h to obtain sodium carboxymethyl cellulose / anthocyanin dispersion.

[0044] The preparation method of the said soy protein isolate / sericin protein dispersion includes the following steps: Add 0.5 - 1 g of soy protein isolate and 0.5 - 2 g of sericin protein to water in a round-bottom flask. Adjust the temperature to 60 - 70 °C and the stirring speed to 250 - 350 r / min. Stir and mix the soy protein isolate and sericin protein solutions evenly to obtain a soy protein isolate / sericin protein dispersion.

[0045] The preparation method of the carboxymethyl cellulose sodium / anthocyanin / soy protein isolate / sericin protein dispersion includes the following steps: Place 20 g of the carboxymethyl cellulose sodium / anthocyanin dispersion in a round-bottom flask. While stirring, use a constant-pressure dropping funnel to add 30 g of the soy protein isolate / sericin protein dispersion for a polymerization reaction. The reaction temperature is 65 °C and the reaction time is 80 min to obtain the carboxymethyl cellulose sodium / anthocyanin / soy protein isolate / sericin protein dispersion.

[0046] Add glycerol accounting for 30% of the solid content in the carboxymethyl cellulose sodium / anthocyanin / soy protein isolate / sericin protein dispersion to the flask and stir for a reaction. Pour the reacted liquid into a film-forming plate and let it stand at room temperature to dry and form a film, thus obtaining the carboxymethyl cellulose sodium / soy protein isolate / sericin protein / anthocyanin composite film material.

Claims

1. A composite membrane material of sodium carboxymethyl cellulose / soy protein isolate / sericin / anthocyanidin, according to the following weight ratio, characterized in that: Includes the following components: 10-20 g of sodium carboxymethyl cellulose / anthocyanidin dispersion, 20-30 g of soy protein isolate / sericin dispersion, 30-50 g of sodium carboxymethyl cellulose / anthocyanidin / soy protein isolate / sericin dispersion.

2. The sodium carboxymethyl cellulose / soy protein isolate / sericin / anthocyanidin composite membrane material according to claim 1, characterized in that: The preparation method of the sodium carboxymethyl cellulose / anthocyanidin dispersion comprises the following steps: Place 0.8-1 g of sodium carboxymethyl cellulose, 800-2000 g of water, and 0.72-0.9 g of anthocyanin in a round-bottom flask, adjust the stirring speed to 200-300 r / min, and stir at 40-50 °C until completely dissolved. Add 0.4-0.5 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.2-0.25 g of N-hydroxysuccinimide, and continue stirring and reacting at 40-50 °C for 0.5-1 h to obtain a sodium carboxymethyl cellulose / anthocyanin dispersion.

3. The sodium carboxymethyl cellulose / soy protein isolate / sericin / anthocyanidin composite membrane material according to claim 1, characterized in that: The preparation method of the soy protein isolate / sericin dispersion comprises the following steps: Add 0.5-1g of soy protein isolate, 0.5-2g of sericin and water into a round-bottom flask, adjust the temperature to 60-70°C, adjust the stirring speed to 250-350r / min, stir and mix the soy protein isolate and sericin solution evenly to obtain a soy protein isolate / sericin dispersion.

4. The sodium carboxymethyl cellulose / soy protein isolate / sericin / anthocyanidin composite membrane material according to claim 2, characterized in that: The mass ratio of the sodium carboxymethyl cellulose to water is 1:10-20; The mass ratio of the sodium methylcellulose to anthocyanin is 1:0.

9.

5. The sodium carboxymethyl cellulose / soy protein isolate / sericin / anthocyanidin composite membrane material according to claim 3, characterized in that: The mass ratio of the soy protein isolate to water is 1:40-60; The mass ratio of sericin to water is 1:15-40; The mass ratio of the soy protein isolate to the sericin is 1:1-4; The stirring time is 30 to 40 minutes.

6. Sodium carboxymethyl cellulose / soy protein isolate / sericin / anthocyanidin composite membrane material, characterized in that: The preparation method of the sodium carboxymethyl cellulose / anthocyanidin / soy protein isolate / sericin dispersion comprises the following steps: Place 10-20 g of sodium carboxymethyl cellulose / anthocyanidin dispersion in a round-bottom flask, and add 20-30 g of soy protein isolate / sericin dispersion dropwise using a constant pressure dropping funnel under stirring to carry out polymerization reaction at a reaction temperature of 60-70°C and a reaction time of 60-90 min to obtain sodium carboxymethyl cellulose / anthocyanidin / soy protein isolate / sericin dispersion.

7. The sodium carboxymethyl cellulose / anthocyanidin / soy protein isolate / sericin dispersion according to claim 6, characterized in that: The mass ratio of sodium carboxymethyl cellulose to soy protein isolate is 1:0.5; The mass ratio of sodium carboxymethyl cellulose to sericin is 1: 0.5-2; The stirring speed is 200-300 r / min.

8. The sodium carboxymethyl cellulose / soy protein isolate / sericin / anthocyanidin composite membrane material according to claim 1, characterized in that: The method for preparing the composite membrane material comprises the following steps: Add sodium carboxymethyl cellulose / anthocyanidin / soy protein isolate / sericin dispersion and glycerol accounting for 20% to 40% of the solid content of the sodium carboxymethyl cellulose / anthocyanidin / soy protein isolate / sericin dispersion into a flask and stir to react. Pour the liquid after the reaction into a film-forming plate and let it stand at room temperature to dry and form a film, thereby obtaining a sodium carboxymethyl cellulose / soy protein isolate / sericin / anthocyanidin composite membrane material.

9. The sodium carboxymethyl cellulose / soy protein isolate / sericin / anthocyanidin composite membrane material according to claim 8, characterized in that: The mass ratio of solid content to glycerol in the sodium carboxymethyl cellulose / anthocyanidin / soy protein isolate / sericin dispersion is 1:0.2-0.4; The stirring reaction has a stirring speed of 200-300 r / min; The stirring reaction time is 60 to 90 minutes; The reaction temperature is 60-70°C.