Bacteriostatic fresh-keeping packaging material for pastries as well as preparation method and application of bacteriostatic fresh-keeping packaging material

Abstract

The invention relates to the technical field of food packaging materials, in particular to a bacteriostatic and fresh-keeping packaging material and a preparation method and application thereof.The bacteriostatic and fresh-keeping packaging material is prepared from, by mass, 180-240 parts of chitosan, 15-25 parts of anthocyanin, 5-15 parts of modified nano-zinc oxide and 300-350 parts of water, the modified nano zinc oxide is modified by a silane coupling agent, and is subjected to physical mixing and ultrasonic treatment. The antibacterial fresh-keeping packaging material has excellent mechanical barrier property and antibacterial property.

Description

Technical Field

[0001] The present invention relates to the technical field of food packaging materials, and in particular to an antibacterial and fresh-keeping packaging material, a preparation method and application thereof. Background Art

[0002] Rice is the most important food crop in my country and the staple food of more than 3 billion people in the world. Rice and rice products occupy an important position in the traditional diet of Chinese residents. With the increase of market and consumer demand, rice products with various processing methods have emerged, including rice cakes, sponge cakes, rice noodles and rice vermicelli, etc., with broad market prospects. However, for pastry products among rice products, such as common rice cakes and sponge cakes, there are problems such as strict storage conditions and short shelf life. Their sensory quality will continue to decline with the extension of storage time. Therefore, in recent years, the issue of developing antiseptic and fresh-keeping packaging materials for pastries has gradually attracted attention.

[0003] Chitosan is a natural alkaline polysaccharide with a wide range of sources, good biocompatibility and biodegradability. It can form composite films with starch, pectin and other substances through intermolecular hydrogen bonds and ionic forces, and has inhibitory effects on a variety of bacteria and good antioxidant capacity, making it have broad application prospects in the field of food antibacterial packaging materials. However, chitosan has a special macromolecular structure and insufficient hydrogen atom donors, resulting in weak biological activity and poor mechanical and barrier properties.

[0004] The existing antiseptic and fresh-keeping packaging materials made of chitosan also have the above-mentioned problems of weak biological activity and poor mechanical barrier properties, and at the same time, the antibacterial properties are also insufficient. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the current chitosan antiseptic and fresh-keeping packaging materials described in the above background technology have poor mechanical barrier properties and insufficient antibacterial properties. An antibacterial and fresh-keeping packaging material and its preparation method and application are proposed. The antibacterial and fresh-keeping packaging material has good mechanical barrier properties and antibacterial properties.

[0006] The technical solution adopted by the present invention to solve the technical problem is: an antibacterial fresh-keeping packaging material, the raw materials of the antibacterial fresh-keeping packaging material include, by weight:

[0007]

[0008] In the present invention, the combination of chitosan and modified nano zinc oxide can effectively make up for the defects of chitosan's mechanical properties. Chitosan and modified nano zinc oxide can produce a synergistic effect, which can not only produce better antibacterial properties and improve the mechanical properties of the film, but also limit the migration of nano zinc oxide to ensure safe use.

[0009] Preferably, the preparation method of the modified nano zinc oxide is: mixing nano zinc oxide with water, ultrasonically treating for 10-20 minutes at a temperature of 35-45°C, adding a silane coupling agent, continuously stirring for 4-6 hours at a temperature of 30-40°C, drying, grinding, and sieving to obtain modified nano zinc oxide, wherein the mass ratio of the nano zinc oxide, water, and silane coupling agent is (4-6): (8-11): (2-3).

[0010] Preferably, the silane coupling agent is KH-550 silane coupling agent.

[0011] Preferably, the sieve mesh number is 40-60 meshes.

[0012] Preferably, the chitosan is β-chitosan, and the molecular weight of the chitosan is 50-300 kDa.

[0013] Preferably, the anthocyanidin is one or more of purple tomato anthocyanidin, blueberry anthocyanidin, purple potato anthocyanidin and proanthocyanidin, and more preferably purple tomato anthocyanidin.

[0014] Preferably, the raw materials of the antibacterial fresh-keeping packaging material are composed of the following components by weight:

[0015]

[0016] Furthermore, the raw materials of the antibacterial fresh-keeping packaging material are composed of the following components by weight:

[0017]

[0018] A method for preparing an antibacterial fresh-keeping packaging material, the method comprising the following steps:

[0019] S1, mixing the chitosan in the formula amount with water, and stirring continuously for 3-5 hours to obtain a chitosan solution;

[0020] S2, mixing the formulated amount of anthocyanidins with the chitosan solution, and continuously stirring for 3-5 hours to obtain a chitosan / anthocyanidin solution;

[0021] S3, mixing the modified nano zinc oxide with the chitosan / anthocyanin solution in the formula amount, and stirring for 3-5 hours to obtain a membrane precursor solution;

[0022] S4. Filter the membrane precursor solution, let it stand, vortex and oscillate for 20-40 minutes, pour it into a mold, and vacuum dry it for 23-25 ​​hours to obtain an antibacterial and fresh-keeping packaging material.

[0023] Preferably, the stirring speed is 700-900 rpm.

[0024] An application of the antibacterial freshness-preserving packaging material as described above in food packaging.

[0025] Preferably, the food is cakes, the antibacterial fresh-keeping packaging material is covered on the surface of the cakes, and stored at 15-25° C., and the mass ratio of the antibacterial fresh-keeping packaging material to the cakes is (0.1-0.3):1.

[0026] The beneficial effects of the present invention are:

[0027] 1. The present invention uses chitosan, anthocyanin and modified nano zinc oxide as main raw materials to prepare antibacterial fresh-keeping packaging. The three work synergistically, so that the antibacterial fresh-keeping packaging has good antibacterial function and antioxidant activity, and the fresh-keeping packaging is non-toxic and harmless, has good biodegradability, and meets green environmental protection requirements.

[0028] 2. The present invention can indicate the freshness of cakes by adding anthocyanins through the change of the color of the antibacterial fresh-keeping packaging.

[0029] 3. The present invention modifies nano zinc oxide by using a silane coupling agent, and improves the molecular dispersibility, stability and compatibility of nano zinc oxide with organic matter through physical stirring and ultrasonic methods, thereby effectively improving the anti-aging performance and antibacterial property of the antibacterial fresh-keeping packaging material. DETAILED DESCRIPTION

[0030] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0032] The present invention is now further described in conjunction with specific examples. The following examples are only for explaining the present invention, but do not constitute a limitation of the present invention. The test samples and test processes used in the following examples include the following (if the specific experimental conditions are not indicated in the examples, they are usually in accordance with conventional conditions or the conditions recommended by the reagent company; the reagents, consumables, etc. used in the following examples, if not otherwise specified, can all be obtained from commercial channels).

[0033] Example 1

[0034] The invention discloses an antibacterial fresh-keeping packaging material. The raw materials of the antibacterial fresh-keeping packaging material consist of the following components by weight: 200 parts of chitosan, 20 parts of anthocyanin, 10 parts of modified nano zinc oxide and 320 parts of deionized water.

[0035] The preparation method of the modified nano zinc oxide is as follows: by weight, 10 parts of nano zinc oxide and 20 parts of deionized water are mixed, ultrasonicated at 40° C. for 15 minutes, then 5 parts of KH-550 silane coupling agent are added, magnetically stirred at 35° C. for 5 hours, dried and then ground, and passed through a 50-mesh sieve to obtain the modified nano zinc oxide.

[0036] The preparation method of the antibacterial fresh-keeping packaging material is as follows:

[0037] S1, mixing the chitosan in the formula amount with deionized water, and stirring magnetically at 800 rpm for 4 h to obtain a chitosan solution;

[0038] S2, mixing the formulated amount of anthocyanidins with the chitosan solution, and magnetically stirring at 800 rpm for 4 h to obtain a chitosan / anthocyanidin solution;

[0039] S3, mixing the modified nano zinc oxide with the chitosan / anthocyanin solution in the formulated amount, and stirring with a magnetic force at 800 rpm for 4 h to obtain a membrane precursor solution;

[0040] S4. Filter the membrane precursor solution, let it stand, vortex and oscillate for 30 minutes, pour it into a mold, and vacuum dry it for 24 hours to obtain an antibacterial and fresh-keeping packaging material.

[0041] Example 2

[0042] The invention discloses an antibacterial fresh-keeping packaging material. The raw materials of the antibacterial fresh-keeping packaging material consist of the following components by weight: 180 parts of chitosan, 15 parts of anthocyanin, 5 parts of modified nano zinc oxide and 300 parts of deionized water.

[0043] The preparation method of the modified nano zinc oxide is as follows: by weight, 10 parts of nano zinc oxide and 20 parts of deionized water are mixed, ultrasonicated at 40° C. for 15 minutes, then 5 parts of KH-550 silane coupling agent are added, magnetically stirred at 35° C. for 5 hours, dried and then ground, and passed through a 50-mesh sieve to obtain the modified nano zinc oxide.

[0044] The preparation method of the antibacterial fresh-keeping packaging material is as follows:

[0045] S1, mixing the chitosan in the formula amount with deionized water, and stirring magnetically at 800 rpm for 4 h to obtain a chitosan solution;

[0046] S2, mixing the formulated amount of anthocyanidins with the chitosan solution, and magnetically stirring at 800 rpm for 4 h to obtain a chitosan / anthocyanidin solution;

[0047] S3, mixing the modified nano zinc oxide with the chitosan / anthocyanin solution in the formulated amount, and stirring with a magnetic force at 800 rpm for 4 h to obtain a membrane precursor solution;

[0048] S4. Filter the membrane precursor solution, let it stand, vortex and oscillate for 30 minutes, pour it into a mold, and vacuum dry it for 24 hours to obtain an antibacterial and fresh-keeping packaging material.

[0049] Example 3

[0050] The invention discloses an antibacterial fresh-keeping packaging material. The raw materials of the antibacterial fresh-keeping packaging material consist of the following components by weight: 240 parts of chitosan, 25 parts of anthocyanin, 15 parts of modified nano zinc oxide and 350 parts of deionized water.

[0051] The preparation method of the modified nano zinc oxide is as follows: by weight, 10 parts of nano zinc oxide and 20 parts of deionized water are mixed, ultrasonicated at 40° C. for 15 minutes, then 5 parts of KH-550 silane coupling agent are added, magnetically stirred at 35° C. for 5 hours, dried and then ground, and passed through a 50-mesh sieve to obtain the modified nano zinc oxide.

[0052] The preparation method of the antibacterial fresh-keeping packaging material is as follows:

[0053] S1, mixing the chitosan in the formula amount with deionized water, and stirring magnetically at 800 rpm for 4 h to obtain a chitosan solution;

[0054] S2, mixing the formulated amount of anthocyanidins with the chitosan solution, and magnetically stirring at 800 rpm for 4 h to obtain a chitosan / anthocyanidin solution;

[0055] S3, mixing the modified nano zinc oxide with the chitosan / anthocyanin solution in the formulated amount, and stirring with a magnetic force at 800 rpm for 4 h to obtain a membrane precursor solution;

[0056] S4. Filter the membrane precursor solution, let it stand, vortex and oscillate for 30 minutes, pour it into a mold, and vacuum dry it for 24 hours to obtain an antibacterial and fresh-keeping packaging material.

[0057] Example 4

[0058] The invention discloses an antibacterial fresh-keeping packaging material. The raw materials of the antibacterial fresh-keeping packaging material consist of the following components by weight: 200 parts of chitosan, 20 parts of anthocyanin, 10 parts of modified nano zinc oxide and 320 parts of deionized water.

[0059] The preparation method of the modified nano zinc oxide is as follows: 12 parts of nano zinc oxide and 22 parts of deionized water are mixed, ultrasonicated at 45° C. for 20 minutes, then 6 parts of KH-550 silane coupling agent are added, magnetically stirred at 40° C. for 6 hours, dried and then ground, and passed through a 60-mesh sieve to obtain the modified nano zinc oxide.

[0060] The preparation method of the antibacterial fresh-keeping packaging material is as follows:

[0061] S1, mixing the chitosan in the formula amount with deionized water, and stirring magnetically at 800 rpm for 4 h to obtain a chitosan solution;

[0062] S2, mixing the formulated amount of anthocyanidins with the chitosan solution, and magnetically stirring at 800 rpm for 4 h to obtain a chitosan / anthocyanidin solution;

[0063] S3, mixing the modified nano zinc oxide with the chitosan / anthocyanin solution in the formulated amount, and stirring with a magnetic force at 800 rpm for 4 h to obtain a membrane precursor solution;

[0064] S4. Filter the membrane precursor solution, let it stand, vortex and oscillate for 30 minutes, pour it into a mold, and vacuum dry it for 24 hours to obtain an antibacterial and fresh-keeping packaging material.

[0065] Example 5

[0066] The invention discloses an antibacterial fresh-keeping packaging material. The raw materials of the antibacterial fresh-keeping packaging material consist of the following components by weight: 200 parts of chitosan, 20 parts of anthocyanin, 10 parts of modified nano zinc oxide and 320 parts of deionized water.

[0067] The preparation method of the modified nano zinc oxide is as follows: 8 parts of nano zinc oxide and 18 parts of deionized water are mixed, ultrasonicated at 35° C. for 10 minutes, then 4 parts of KH-550 silane coupling agent are added, magnetically stirred at 30° C. for 5 hours, dried and ground, and passed through a 40-mesh sieve to obtain the modified nano zinc oxide.

[0068] The preparation method of the antibacterial fresh-keeping packaging material is as follows:

[0069] S1, mixing the chitosan in the formula amount with deionized water, and stirring magnetically at 800 rpm for 4 h to obtain a chitosan solution;

[0070] S2, mixing the formulated amount of anthocyanidins with the chitosan solution, and magnetically stirring at 800 rpm for 4 h to obtain a chitosan / anthocyanidin solution;

[0071] S3, mixing the modified nano zinc oxide with the chitosan / anthocyanin solution in the formulated amount, and stirring with a magnetic force at 800 rpm for 4 h to obtain a membrane precursor solution;

[0072] S4. Filter the membrane precursor solution, let it stand, vortex and oscillate for 30 minutes, pour it into a mold, and vacuum dry it for 24 hours to obtain an antibacterial and fresh-keeping packaging material.

[0073] Comparative Example 1

[0074] An antibacterial fresh-keeping packaging material. The preparation method of the antibacterial fresh-keeping packaging material is the same as that of Example 1, except that nano zinc oxide is used instead of modified nano zinc oxide.

[0075] Comparative Example 2

[0076] The invention discloses an antibacterial fresh-keeping packaging material. The raw materials of the antibacterial fresh-keeping packaging material consist of the following components by weight: 200 parts of chitosan, 20 parts of anthocyanin and 320 parts of deionized water.

[0077] The preparation method of the antibacterial fresh-keeping packaging material is as follows:

[0078] S1, mixing the chitosan in the formula amount with deionized water, and stirring magnetically at 800 rpm for 4 h to obtain a chitosan solution;

[0079] S2, mixing the formulated amount of anthocyanidins with the chitosan solution, and magnetically stirring at 800 rpm for 4 h to obtain a chitosan / anthocyanidin solution;

[0080] S4. Filter the chitosan / anthocyanidin solution, let it stand, vortex and oscillate for 30 minutes, pour it into a mold, and vacuum dry it for 24 hours to obtain an antibacterial and fresh-keeping packaging material.

[0081] Comparative Example 3

[0082] An antibacterial fresh-keeping packaging material. The preparation method of the antibacterial fresh-keeping packaging material is the same as that of Example 1, except that the amount of anthocyanidins added is reduced from 20 parts to 5 parts.

[0083] Application Examples 1-8

[0084] The antibacterial fresh-keeping packaging materials prepared in Examples 1-5 and Comparative Examples 1-3 were respectively applied to fermented rice cakes. The application of fermented rice cakes in Examples 1-5 was recorded as Application Examples 1-5, and the application of fermented rice cakes in Comparative Examples 1-3 was recorded as Application Examples 6-8.

[0085] The specific application steps are: covering the surface of the fermented rice cake with the antibacterial fresh-keeping packaging material, and storing it in a constant temperature box at 20°C, wherein the mass ratio of the antibacterial fresh-keeping packaging material to the cake is 0.2:1.

[0086] Application Example 9

[0087] Store the fermented rice cake directly in a constant temperature box at 20°C.

[0088] Experimental Example 1

[0089] pH sensitivity test: The antibacterial fresh-keeping packaging materials prepared in Examples 1-5 and Comparative Examples 1-3 were cut into 2 cm × 2 cm pieces, immersed in citric acid / sodium hydrogen phosphate buffer solutions with pH values ​​of 2, 7 and 12 for 5 min, and the films were taken out and dried at room temperature. The L*, a* and b* values ​​of the samples were measured and recorded using a colorimeter, and repeated 3 times. The results are shown in Table 1.

[0090] Table 1 pH sensitivity results of antibacterial fresh-keeping packaging materials prepared in Examples 1-5 and Comparative Examples 1-3

[0091]

[0092]

[0093] As can be seen from Table 1, the color change of Example 1 is the most obvious. As the pH increases, the color of the film changes from dark red to light red and then to light yellow. This is because, as the pH changes from 2 to 7, the anthocyanin structure in the film changes from a chalconate cation to a quinone-type base, and the corresponding color changes from red to purple. As the pH changes from 7 to 12, anthocyanins change to chalcone and the color also changes to yellow. The color sensitivity of Examples 2-5 and Comparative Examples 1 and 2 to pH changes is slightly reduced, and the color change of Comparative Example 3 is the most vague. This may be because when the anthocyanin content is low, hydrolysis reaction is prone to occur, and colorless methanol methyl alkali is generated; when the chitosan content is high, chitosan, as an alkaline polysaccharide, can cause anthocyanins to lose hydrogen ions and generate blue quinone-type bases. The above results show that the film of Example 1 has the potential to indicate the freshness of fermented rice cakes and can be used as a pH-sensitive indicator membrane for real-time quality monitoring.

[0094] Experimental Example 2

[0095] Antibacterial performance test: The antibacterial fresh-keeping packaging materials prepared in Examples 1-5 and Comparative Examples 1-3 were cut into discs with a diameter of 8 mm and sterilized by ultraviolet light. The bacterial suspension with adjusted concentration was poured into the culture medium of the plate and evenly coated. The film discs were placed on the plate, 3 discs per plate, repeated 3 times, and cultured in a constant temperature incubator at 37°C for 24 hours, and the size of the antibacterial zone was measured. The test results are shown in Table 2.

[0096] Table 2 Antibacterial performance results of antibacterial fresh-keeping packaging materials prepared in Examples 1-5 and Comparative Examples 1-3

[0097]

[0098] It can be seen from Table 2 that the antibacterial fresh-keeping packaging material for cakes described in the present invention has a good antibacterial effect. Compared with comparative examples 1-3, the antibacterial effect of Examples 1-5 is significantly improved. The diameter of the antibacterial circle of Staphylococcus aureus, Escherichia coli and Salmonella in Example 1 is the largest. By comparing Example 1 with Examples 2-3, it can be seen that different packaging material formulas can affect the antibacterial effect, among which Example 1 is the best ratio; by comparing Example 1 with Examples 4-5, it can be seen that different modified nano zinc oxide preparation parameters can also affect the antibacterial effect; by comparing Example 1 with Comparative Examples 1-3, it can be seen that the addition of modified nano zinc oxide and anthocyanins described in the present invention can significantly improve the antibacterial performance of the antibacterial fresh-keeping material.

[0099] Experimental Example 3

[0100] Hardness change test: The fermented rice cakes of Examples 1-9 were placed at 15°C for 24, 48, and 72 hours, and the hardness change of the fermented rice cakes was measured using a texture analyzer, and repeated 3 times. The evaluation results are shown in Table 3.

[0101] Table 3 Hardness test results of fermented rice cakes of application examples 1-9

[0102]

[0103]

[0104] As can be seen from Table 3, the antibacterial fresh-keeping packaging material of the present invention has a good fresh-keeping effect in fermented rice cakes. Compared with Application Examples 6-9, the hardness of the fermented rice cakes in Application Examples 1-5 changes slowly over time. The water loss in Application Example 1 is the slowest, resulting in a slow increase in the hardness of the fermented rice cake. By comparing Application Example 1 with Application Examples 2-5, it can be seen that different packaging material formulas can affect the fresh-keeping effect, among which Application Example 1 has better water-locking performance; by comparing Application Example 1 with Application Example 6, it can be seen that different modified nano zinc oxide preparation parameters can also affect the fresh-keeping effect; by comparing Application Example 1 with Application Examples 7-8, it can be seen that the modified nano zinc oxide of the present invention has a better fresh-keeping effect than nano zinc oxide; by comparing Application Example 1 with Application Example 9, it can be seen that the fermented rice cakes not covered with antibacterial fresh-keeping packaging materials are prone to water loss and hardening, and the shelf life is correspondingly shorter.

[0105] Experimental Example 4

[0106] Mechanical property test: The antibacterial fresh-keeping packaging materials prepared in Examples 1-5 and Comparative Examples 1-3 were cut into dumbbell-shaped strips with a width of 10 mm and a length of 50 mm, and tested using a single-column tensile testing machine with a tensile speed of 1 mm / s. The test results are shown in Table 4.

[0107] Table 4 Mechanical properties test results of antibacterial fresh-keeping packaging materials prepared in Examples 1-5 and Comparative Examples 1-3

[0108]

[0109]

[0110] It can be seen from Table 4 that the antibacterial fresh-keeping packaging material of the present invention has good mechanical properties. Comparison of Example 1 and Comparative Example 1 shows that the mechanical properties of modified nano zinc oxide are better than those of nano zinc oxide; Comparison of Example 1 and Comparative Example 2 shows that modified nano zinc oxide can cooperate with chitosan to significantly improve the mechanical properties of antibacterial fresh-keeping packaging materials; It can be seen from Examples 1-5 that different packaging material formulas and different preparation parameters of modified nano zinc oxide have an impact on the mechanical properties of the material, and Example 1 has the best mechanical properties.

[0111] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0112] The above is a detailed introduction to an antibacterial fresh-keeping packaging material provided by the present invention, its preparation method and application. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. An antibacterial fresh-keeping packaging material, characterized in that: The raw materials of the antibacterial fresh-keeping packaging material include, by weight:

2. The antibacterial fresh-keeping packaging material according to claim 1, characterized in that: The preparation method of the modified nano zinc oxide is as follows: nano zinc oxide is mixed with water, subjected to ultrasonic treatment at a temperature of 35-45° C. for 10-20 minutes, a silane coupling agent is added, the mixture is continuously stirred at a temperature of 30-40° C. for 4-6 hours, dried, ground, and sieved to obtain the modified nano zinc oxide, wherein the mass ratio of the nano zinc oxide, water, and silane coupling agent is (4-6):(8-11):(2-3).

3. The antibacterial fresh-keeping packaging material according to claim 2, characterized in that: The sieving mesh number is 40-60 meshes.

4. The antibacterial fresh-keeping packaging material according to claim 1, characterized in that: The chitosan is β-chitosan, and the molecular weight of the chitosan is 50-300 kDa.

5. The antibacterial fresh-keeping packaging material according to claim 1, characterized in that: The anthocyanidin is one or more of purple tomato anthocyanidin, blueberry anthocyanidin, purple potato anthocyanidin and proanthocyanidin.

6. The antibacterial fresh-keeping packaging material according to claim 1, characterized in that: The raw materials of the antibacterial fresh-keeping packaging material are composed of the following components by weight:

7. A method for preparing an antibacterial fresh-keeping packaging material, characterized in that: The preparation method comprises the following steps: S1, mixing the chitosan in the formula amount with water, and stirring continuously for 3-5 hours to obtain a chitosan solution; S2, mixing the formulated amount of anthocyanidins with the chitosan solution, and continuously stirring for 3-5 hours to obtain a chitosan / anthocyanidin solution; S3, mixing the modified nano zinc oxide with the chitosan / anthocyanin solution in the formula amount, and stirring for 3-5 hours to obtain a membrane precursor solution; S4. Filter the membrane precursor solution, let it stand, vortex and oscillate for 20-40 minutes, pour it into a mold, and vacuum dry it for 23-25 ​​hours to obtain an antibacterial and fresh-keeping packaging material.

8. The preparation method according to claim 7, characterized in that: The stirring speed of the stirring is 700-900 rpm.

9. Use of the antibacterial fresh-keeping packaging material according to claim 1 in food packaging.

10. The use according to claim 9, characterized in that: The food is cakes, the antibacterial fresh-keeping packaging material is covered on the surface of the cakes, and the cakes are stored at 15-25° C., and the mass ratio of the antibacterial fresh-keeping packaging material to the cakes is (0.1-0.3):1.

Images