Nano titanium dioxide bacteriostatic packaging material with high tannic acid loading capacity, preparation method and application of nano titanium dioxide bacteriostatic packaging material

Abstract

The invention relates to the related technical field of food processing. The invention relates to a packaging material, in particular to a high-tannic-acid-loading nano titanium dioxide antibacterial packaging material, a preparation method and application thereof. According to the preparation method, the capacity of loading a bacteriostatic agent tannic acid on mesoporous nano titanium dioxide is improved through amination modification, amination modified nano titanium dioxide loaded with high tannic acid is prepared, polyethylene glycol and glycerol are used as plasticizers, a polylactic acid base material is embedded, and the nano titanium dioxide loaded with high tannic acid is prepared. Further, the high-tannic-acid-loading nano titanium dioxide bacteriostatic packaging material with good tannic acid loading, antibacterial performance, oxidation resistance and fresh-keeping effect is prepared, and a new bacteriostatic packaging choice is provided for the food processing industry.

Description

Technical Field

[0001] The present invention relates to the technical field related to food processing, and more specifically, to a nano titanium dioxide antibacterial packaging material with high tannic acid loading, a preparation method and use thereof. Background Art

[0002] With the growth of global food consumption and the increase in demand for personalized food, the food industry has an increasing demand for packaging materials. Traditional food packaging materials are mainly plastic and paper products. Although these materials are effective in preventing contamination and physical damage, they are insufficient in terms of antibacterial performance and extending the shelf life of food. The growth of spoilage bacteria is one of the main causes of food spoilage. Developing packaging materials with excellent antibacterial functions to control the growth and reproduction of spoilage bacteria has become an effective strategy to extend the shelf life of food.

[0003] Tannic acid is a natural polyphenol compound with good antioxidant and antibacterial properties. It can effectively inhibit the growth of oxidative deterioration and spoilage bacteria in food, thereby extending the shelf life of food. However, its application in packaging materials is affected by its solubility and dispersibility, and it is impossible to achieve efficient loading and dispersion of tannic acid. Nano-titanium dioxide has become an effective carrier of antibacterial substances such as tannic acid due to its excellent photocatalytic properties, antibacterial properties and chemical stability. Nano-titanium dioxide has good biocompatibility and can ensure food safety when in contact with food. Nano-titanium dioxide can produce free radicals with strong oxidizing ability that inhibit the growth of microorganisms under ultraviolet light, but its ability to inhibit microbial growth is limited under visible light conditions. Summary of the invention

[0004] In order to solve the above technical problems, the present invention functionally modifies the surface of nano-titanium dioxide, introduces affinity groups of antibacterial substances, increases the loading amount of antibacterial substances such as tannic acid, and constructs a nano-titanium dioxide antibacterial packaging material with high loading of tannic acid, a preparation method and its application, so as to overcome the above defects and enhance the antibacterial and antioxidant effects. The antibacterial packaging material obtained by the present invention has good tannic acid loading, antibacterial properties, antioxidant properties and fresh-keeping effects, and is suitable for the preservation of livestock and poultry meat and other foods.

[0005] Specifically, the first aspect of the present invention provides a high tannic acid loaded nano titanium dioxide antibacterial packaging material, which comprises the following raw materials by weight: 90 to 110 parts of polylactic acid, 50 to 70 parts of plasticizer, and 10 to 18 parts of high tannic acid loaded nano titanium dioxide;

[0006] The preparation method of high tannic acid loaded nano titanium dioxide is as follows: amino modified mesoporous nano titanium dioxide and tannic acid are mixed in a solvent at a mass ratio of 10:3-18, and loaded to obtain high tannic acid loaded nano titanium dioxide.

[0007] In one embodiment, the preparation method of the amino-modified mesoporous nano-titanium dioxide is to disperse the mesoporous nano-titanium dioxide in methanol, add carbonamide and histidine, and react to obtain the amino-modified mesoporous nano-titanium dioxide.

[0008] In one embodiment, the mass ratio of the mesoporous nano-titanium dioxide, carbonamide, and histidine is 15:9 to 13:5.

[0009] In one embodiment, the reaction temperature is 60-85°C.

[0010] In one embodiment, the plasticizer is a mixture of polyethylene glycol and glycerol in a mass ratio of 2 to 10:1.

[0011] In one embodiment, the load temperature is 55-65°C.

[0012] In one embodiment, the solvent is ethanol.

[0013] The second aspect of the present invention provides a method for preparing a nano titanium dioxide antibacterial packaging material with high tannic acid loading, the preparation method comprising the following steps:

[0014] (1) taking materials by weight, dissolving polylactic acid in dichloromethane, adding a plasticizer, and reacting;

[0015] (2) After the reaction is completed, adding nano-titanium dioxide loaded with high tannic acid, stirring and dispersing, ultrasonic degassing, coating and film forming, and obtaining nano-titanium dioxide antibacterial packaging material loaded with high tannic acid.

[0016] In one embodiment, the reaction temperature is 40-60°C.

[0017] The third aspect of the present invention provides a use of a nano titanium dioxide antibacterial packaging material with a high tannic acid load for preserving livestock and poultry meat products.

[0018] Beneficial effects:

[0019] The present invention improves the ability of mesoporous nano-titanium dioxide to load the antibacterial agent tannic acid through amino modification, prepares amino-modified nano-titanium dioxide with high tannic acid loading, uses polyethylene glycol and glycerol as plasticizers, and embeds a polylactic acid substrate to further prepare a nano-titanium dioxide antibacterial packaging material with high tannic acid loading, good tannic acid loading, antibacterial property, antioxidant property and fresh-keeping effect, providing a new antibacterial packaging option for the food processing industry.

[0020] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The nano titanium dioxide with high tannic acid loading in Example 1;

[0022] Figure 2 This is the X-ray diffraction pattern of nano titanium dioxide with high tannic acid loading in Example 1;

[0023] Figure 3 The nano titanium dioxide antibacterial packaging material with high tannic acid loading in Example 1;

[0024] Figure 4 The antibacterial ability of the nano-titanium dioxide antibacterial packaging material with high tannic acid loading in the example and the material in comparative example 1. DETAILED DESCRIPTION

[0025] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. In the event of a conflict, the definitions in this specification shall prevail.

[0026] Unless otherwise indicated, all percentages, parts, ratios, etc. are by weight.

[0027] As used herein, the terms "comprises," "comprising," "having," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that includes a list of elements is not necessarily limited to only those elements but may also include other elements not expressly listed or inherent to the composition, process, method, article, or apparatus.

[0028] When quantity, weight parts or other numerical value or parameter are given with range, preferred range or a series of upper preferred value and lower preferred value, it should be understood that it specifically discloses all ranges formed by any pair of numerical values ​​of any larger range limit or preferred value and any smaller range limit or preferred value, regardless of whether the range is disclosed respectively. For example, when describing the range of "1 to 5", the described range should be understood to include the range of "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc. Unless otherwise stated, in the description of numerical range herein, the range is intended to include the range end value and all integers, fractions, decimals, etc. within the range.

[0029] In addition, the indefinite articles "a" and "an" before the elements or components of the present disclosure are intended to indicate that the number of occurrences (i.e., occurrences) of the elements or components is not limited. Therefore, "a" or "an" should be understood to include one or at least one, unless it is clearly indicated that the number is singular, otherwise the elements or components in the singular form also include the plural case.

[0030] Unless specifically stated, the materials, methods, and examples described herein are illustrative only and not limiting. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, suitable methods and materials are still described herein.

[0031] The present disclosure is described in detail below.

[0032] The present invention provides a high tannic acid loaded nano titanium dioxide antibacterial packaging material, which comprises the following raw materials by weight: 90 to 110 parts of polylactic acid, 50 to 65 parts of plasticizer, and 10 to 18 parts of high tannic acid loaded nano titanium dioxide;

[0033] The preparation method of high tannic acid loaded nano titanium dioxide is as follows: amino modified mesoporous nano titanium dioxide and tannic acid are mixed in a solvent at a mass ratio of 10:3-18, and loaded to obtain high tannic acid loaded nano titanium dioxide.

[0034] Highly tannic acid-loaded nano titanium dioxide: The antibacterial substance tannic acid is loaded on the surface of amino-modified mesoporous nano titanium dioxide. Tannic acid is a naturally occurring polyphenol substance. The phenolic hydroxyl group can effectively couple with oxygen in the environment and slow down the oxidation process of food. Tannic acid interacts with spoilage bacteria such as Pseudomonas, destroys the bacterial structure, inhibits the growth and reproduction of spoilage bacteria, and thus delays the spoilage of food.

[0035] Among them, amino-modified mesoporous nano-titanium dioxide: mesoporous nano-titanium dioxide has good photocatalytic properties, and the active substances such as singlet oxygen, superoxide radicals and hydroxyl radicals produced can effectively inhibit the growth of food spoilage bacteria; the surface of nano-titanium dioxide contains rich titanium hydroxyl groups, which is easy to be amino-modified, has many active sites and a large specific surface area, and is suitable for the efficient loading of functional substances.

[0036] In this process, carbonamide and histidine are used as functional factors to modify the surface hydroxyl groups of mesoporous nano-titanium dioxide, and amino groups are coupled to make it functional. The mesoporous nano-titanium dioxide can react better when the concentration in methanol is 0.25-1.50wt%.

[0037] Regarding the reaction temperature of the amination reaction, a more favorable temperature is 60 to 85° C., and the reaction time is 3 to 5 hours.

[0038] Regarding the ratio of raw materials in the amination process, the mass ratio of mesoporous nano-titanium dioxide, carbonamide, and histidine is 15:9 to 13:5.

[0039] The second aspect of the present invention provides a method for preparing a nano titanium dioxide antibacterial packaging material with a high load of tannic acid, comprising:

[0040] (1) taking materials by weight, dissolving polylactic acid in dichloromethane, adding a plasticizer, and reacting;

[0041] (2) After the reaction is completed, adding nano-titanium dioxide loaded with high tannic acid, stirring and dispersing, ultrasonic degassing, coating and film forming, and obtaining nano-titanium dioxide antibacterial packaging material loaded with high tannic acid.

[0042] In step (1), polylactic acid is plasticized and modified: polylactic acid is a new type of biodegradable packaging substrate and a potential substitute for petroleum-based plastics. It has good processing properties, mechanical properties, and safety performance and has great application potential in the field of food packaging.

[0043] There is no particular limitation on the plasticizer, which may be any of those conventionally used in the art. Advantageously, the plasticizer is a plasticizer molecule containing a polyhydroxyl group, preferably a mixture of polyethylene glycol and glycerol in a mass ratio of 2 to 10:1.

[0044] In step (2), the mesoporous nano-titanium dioxide with high tannic acid loading is cross-linked and polymerized with polylactic acid, polyethylene glycol and glycerol to form a film, thereby obtaining the mesoporous nano-titanium dioxide antibacterial packaging material with high tannic acid loading. The mesoporous nano-titanium dioxide is amino-modified by polyamino molecules to enhance the ability of the mesoporous nano-titanium dioxide to load the antibacterial agent tannic acid, thereby solving the problems of low tannic acid loading rate and poor dispersibility of the packaging material, improving the antibacterial performance of the mesoporous nano-titanium dioxide, and obtaining amino-modified nano-titanium dioxide with high tannic acid loading. The preferred polyethylene glycol and glycerol are used as plasticizers, and the polylactic acid substrate is embedded to obtain the nano-titanium dioxide antibacterial packaging material with high tannic acid loading, good antibacterial performance, antioxidant performance and fresh-keeping effect. The nano-titanium dioxide antibacterial packaging material with high tannic acid loading, good antibacterial performance, antioxidant performance and fresh-keeping effect is prepared. The nano-titanium dioxide antibacterial packaging material has great application potential in meat packaging, and provides a degradable, highly effective antibacterial and antioxidant packaging material for the food processing industry.

[0045] The concentration of the amino modified mesoporous nano titanium dioxide in ethanol is 0.50-1.50wt%, and the tannic acid loading rate is not less than 70% of the mass of the mesoporous nano titanium dioxide.

[0046] The invention also provides a nano titanium dioxide antibacterial packaging material with a high tannic acid load, which is prepared by the preparation method of the nano titanium dioxide antibacterial packaging material with a high tannic acid load.

[0047] The embodiments of the present application also provide the use of nano-titanium dioxide antibacterial packaging materials with high tannic acid load for food processing and preservation. Regarding food, any one or a combination of livestock, poultry, aquatic products, eggs, dairy products, and vegetable foods can be selected; the preferred choice is livestock and poultry meat.

[0048] Experimental supplies description:

[0049] Test strain: Pseudomonas azotoformans (MN10), isolated, identified and supplied from fresh meat by the Meat Science and Nutrition Engineering Innovation Team of the Institute of Agro-product Processing, Chinese Academy of Agricultural Sciences.

[0050] Main chemical reagents: nano-titanium dioxide (CAS No. 13463-67-7), polyethylene glycol (CAS No. 25322-68-3), glycerol (CAS No. 56-81-5), purchased from Shanghai McLean Biochemical Technology Co., Ltd.; tannic acid (CAS No. 5424-20-4), purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0051] Main instruments and equipment: D2 PHASERX diffractometer, Bruker Corporation.

[0052] Test method:

[0053] X-ray diffraction pattern test: weigh 0.50g of sample, place it on the equipment test platform, and measure the angle range of 5° to 60° at room temperature to analyze the structure of nano-titanium dioxide antibacterial material with high tannic acid load.

[0054] Antibacterial experiment: After the food spoilage bacteria are amplified and cultured, they are used to evaluate the antibacterial effect of antibacterial materials. 5 Pseudomonas with a CFU / mL was co-cultured with nano-titanium dioxide with a high load of tannic acid of 0.1 mg / mL, and its colony changes were tested under visible light conditions to analyze the antibacterial properties of nano-titanium dioxide antibacterial materials with a high load of tannic acid.

[0055] Antioxidant experiment: Prepare a certain amount of DPPH solution, add 0.05 mg / L of nano-titanium dioxide solution with high tannic acid load, mix well, react in the dark for 20 minutes, measure the absorbance value A517 at 517 nm, use ascorbic acid as a positive control, and analyze the antioxidant properties of nano-titanium dioxide antibacterial materials with high tannic acid load.

[0056] Freshness preservation experiment: 50.0g of fresh pork was packed with nano-titanium dioxide antibacterial packaging materials with different tannic acid loads, placed under refrigerated conditions of 0-4℃, and after visible light treatment, the freshness of the fresh pork at different storage times was analyzed.

[0057] Example 1

[0058] A method for preparing a nano titanium dioxide antibacterial packaging material with high tannic acid loading, comprising the following steps:

[0059] S1: Preparation of amino-modified mesoporous nano-titanium dioxide

[0060] Weigh 1.50 g of mesoporous nano-titanium dioxide, evenly disperse it in a single-necked flask containing 100.00 mL of methanol solution, ultrasonically treat for 10 min, add 1.20 g of carbonamide and 0.50 g of histidine in sequence, stir to dissolve, and react at 70 ° C for 2 h to obtain amino-modified mesoporous nano-titanium dioxide;

[0061] S2: Loading the antibacterial substance tannic acid on the surface of amino-modified mesoporous nano-titanium dioxide

[0062] Weigh 1.50 g of the product obtained in S1, evenly disperse it in a single-necked flask containing 100.00 mL of ethanol, stir and dissolve it, then add 1.50 g of tannic acid, an antibacterial substance, and react at 60 ° C for 3 h to load tannic acid on the surface of amino-modified mesoporous nano-titanium dioxide to obtain mesoporous nano-titanium dioxide with high tannic acid loading;

[0063] S3: Dissolve polylactic acid in dichloromethane for plasticization modification

[0064] Weigh 10.00 g of polylactic acid and evenly disperse it in a single-necked flask containing 100.00 mL of dichloromethane solution. After stirring and dissolving, add 5.00 g of polyethylene glycol and 2.00 g of glycerol in sequence, and react at 40° C. for 2 h to obtain a plasticized polylactic acid solution.

[0065] S4: Preparation of nano-titanium dioxide antibacterial packaging materials with high tannic acid loading

[0066] Weigh 1.50 g of the product obtained in S2, i.e., mesoporous nano-titanium dioxide with high tannic acid loading, and disperse it in the plasticized polylactic acid solution obtained in S3 by stirring. Perform ultrasonic degassing for 1 h, apply coating to form a film, and obtain nano-titanium dioxide antibacterial packaging material with high tannic acid loading.

[0067] Embodiment 2:

[0068] A method for preparing a nano titanium dioxide antibacterial packaging material with high tannic acid loading, comprising the following steps:

[0069] S1: Preparation of amino-modified mesoporous nano-titanium dioxide

[0070] Weigh 1.50 g of mesoporous nano-titanium dioxide, evenly disperse it in a single-necked flask containing 100.00 mL of methanol solution, ultrasonically treat for 10 min, add 1.20 g of carbonamide and 0.50 g of histidine in sequence, stir to dissolve, and react at 70 ° C for 2 h to obtain amino-modified mesoporous nano-titanium dioxide;

[0071] S2: Loading the antibacterial substance tannic acid on the surface of amino-modified mesoporous nano-titanium dioxide

[0072] Weigh 1.50 g of the product obtained in S1, evenly disperse it in a single-necked flask containing 100.00 mL of ethanol solution, stir and dissolve it, then add 1.00 g of tannic acid, an antibacterial substance, and react at 60 ° C for 3 h to load tannic acid on the surface of amino-modified mesoporous nano-titanium dioxide to obtain mesoporous nano-titanium dioxide with high tannic acid loading;

[0073] S3: Dissolve polylactic acid in dichloromethane for plasticization modification

[0074] Weigh 10.00 g of polylactic acid and evenly disperse it in a single-necked flask containing 100.00 mL of dichloromethane solution. After stirring and dissolving, add 5.00 g of polyethylene glycol and 2.00 g of glycerol in sequence, and react at 40° C. for 2 h to obtain a plasticized polylactic acid solution.

[0075] S4: Preparation of nano-titanium dioxide antibacterial packaging materials with high tannic acid loading

[0076] Weigh 1.50 g of the product obtained in S2, i.e., mesoporous nano-titanium dioxide with high tannic acid loading, and disperse it in the plasticized polylactic acid solution obtained in S3 by stirring. Perform ultrasonic degassing for 1 h, apply coating to form a film, and obtain nano-titanium dioxide antibacterial packaging material with high tannic acid loading.

[0077] Embodiment 3:

[0078] A method for preparing a nano titanium dioxide antibacterial packaging material with high tannic acid loading, comprising the following steps:

[0079] S1: Preparation of amino-modified mesoporous nano-titanium dioxide

[0080] Weigh 1.50 g of mesoporous nano-titanium dioxide, evenly disperse it in a single-necked flask containing 100.00 mL of methanol solution, ultrasonically treat for 10 min, add 1.20 g of carbonamide and 0.50 g of histidine in sequence, stir to dissolve, and react at 70 ° C for 2 h to obtain amino-modified mesoporous nano-titanium dioxide;

[0081] S2: Loading the antibacterial substance tannic acid on the surface of amino-modified mesoporous nano-titanium dioxide

[0082] Weigh 1.50 g of the product obtained in S1, evenly disperse it in a single-necked flask containing 100.00 mL of ethanol solution, stir and dissolve it, add 0.50 g of tannic acid, an antibacterial substance, and react at 60 ° C for 3 h to load tannic acid on the surface of amino-modified mesoporous nano-titanium dioxide to obtain high tannic acid-loaded mesoporous nano-titanium dioxide;

[0083] S3: Dissolve polylactic acid in dichloromethane for plasticization modification

[0084] Weigh 10.00 g of polylactic acid and evenly disperse it in a single-necked flask containing 100.00 mL of dichloromethane solution. After stirring and dissolving, add 5.00 g of polyethylene glycol and 2.00 g of glycerol in sequence, and react at 40° C. for 2 h to obtain a plasticized polylactic acid solution.

[0085] S4: Preparation of nano-titanium dioxide antibacterial packaging materials with high tannic acid loading

[0086] Weigh 1.50 g of the product obtained in S2, i.e., mesoporous nano-titanium dioxide with high tannic acid loading, and disperse it in the plasticized polylactic acid solution obtained in S3 by stirring. Perform ultrasonic degassing for 1 h, apply coating to form a film, and obtain nano-titanium dioxide antibacterial packaging material with high tannic acid loading.

[0087] Comparative Example 1:

[0088] A method for preparing a tannic acid-loaded nano-titanium dioxide antibacterial packaging material comprises the following steps:

[0089] S1: Loading the antibacterial substance tannic acid on the surface of mesoporous nano-titanium dioxide

[0090] Weigh 1.50 g of mesoporous nano-titanium dioxide, evenly disperse it in a single-necked flask containing 100.00 mL of ethanol solution, stir and dissolve it, add 1.50 g of antibacterial substance tannic acid, react at 60° C. for 3 h, load tannic acid on the surface of mesoporous nano-titanium dioxide, and obtain tannic acid-loaded mesoporous nano-titanium dioxide;

[0091] S2: Dissolve polylactic acid in dichloromethane for plasticization modification

[0092] Weigh 10.00 g of polylactic acid and evenly disperse it in a single-necked flask containing 100.00 mL of dichloromethane solution. After stirring and dissolving, add 5.00 g of polyethylene glycol and 2.00 g of glycerol in sequence, and react at 40° C. for 2 h to obtain a plasticized polylactic acid solution.

[0093] S3: Preparation of nano-titanium dioxide antibacterial packaging materials with high tannic acid loading

[0094] Weigh 1.50 g of the product obtained in S1, namely, mesoporous nano-titanium dioxide loaded with tannic acid, and disperse it in the plasticized polylactic acid solution obtained in S2 by stirring. Degassing by ultrasonication for 1 h, coating and film-forming, and obtaining the nano-titanium dioxide antibacterial packaging material loaded with tannic acid.

[0095] Comparative Example 2

[0096] Substantially the same as Example 1 except for the lack of carbamide.

[0097] Comparative Example 3

[0098] It is essentially the same as Example 1 except that histidine is missing.

[0099] like Figure 1 As shown, compared with the non-amino-modified mesoporous nano-titanium dioxide loaded with tannic acid packaging materials, the amino-modified mesoporous nano-titanium dioxide with high loading of tannic acid has better antibacterial effect, and its inhibition rate against Pseudomonas is nearly 100%. It has great application potential in foods with Pseudomonas as characteristic spoilage bacteria.

[0100] Table 1 Antibacterial rate, antioxidant capacity and preservation effect of nano-titanium dioxide packaging materials with high tannic acid loading

[0101]

[0102] From the above results, it can be seen that amino-modified mesoporous nano-titanium dioxide can increase the loading amount of tannic acid, thereby improving the antibacterial and antioxidant properties of tannic acid-loaded nano-titanium dioxide. It has application potential in inhibiting food spoilage bacteria, especially Pseudomonas, the dominant spoilage bacteria in livestock and poultry meat, and provides a new antibacterial packaging material for food spoilage bacteria control and quality maintenance.

[0103] like Figure 2As shown in the figure, the amino-modified mesoporous nano-titanium dioxide with high tannic acid loading prepared by S2 has significant differences from the white nano-titanium dioxide without tannic acid loading, indicating that tannic acid has been combined with mesoporous nano-titanium dioxide, laying the foundation for the preparation of nano-titanium dioxide antibacterial packaging materials. Compared with reported amino-modified reagents such as polyaniline and ethylenediamine, the carbonamide and histidine used in S1 have better biocompatibility and safety, and the molecular chain is shorter, which can bind more tannic acid molecules, which is conducive to the realization of high-load tannic acid. The proportion of tannic acid loaded on the amino-modified mesoporous nano-titanium dioxide obtained by S2 exceeds that of the unamino-modified mesoporous nano-titanium dioxide. Compared with the existing amino-modified nano-titanium dioxide preparation process, S2 has the characteristics of mild reaction temperature, short reaction cycle, simple operation, etc., and is suitable for large-scale production. In addition, the particle size of the amino-modified mesoporous nano-titanium dioxide is 20nm~40nm, the specific surface area is high, and the affinity with the polylactic acid substrate is strong, which improves the uniformity of the antibacterial packaging material. The polylactic acid solution obtained in S3 has better dispersion of amino-modified mesoporous nano-titanium dioxide than the unplasticized polylactic acid, which improves the stability of the reaction system and provides a basis for S4.

[0104] like Figure 3 As shown in the figure, the crystal structure of mesoporous nano-titanium dioxide with high loading of tannic acid is intact, and the typical characteristic peaks of mesoporous nano-titanium dioxide are still retained, indicating that the loading method of tannic acid does not affect the crystal form of mesoporous nano-titanium dioxide, the reaction conditions are mild, and it has the potential for large-scale production. Figure 4 The nano-titanium dioxide antibacterial packaging material with high tannic acid loading has good light transmittance and flexibility, and can meet the processing requirements of food packaging.

[0105] The number of equipment and processing scale described here are used to simplify the description of the present invention. The application, modification and variation of the nano-titanium dioxide antibacterial packaging material with high tannic acid loading and its preparation method and use of the present invention are obvious to those skilled in the art.

[0106] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A high tannic acid loaded nano titanium dioxide antibacterial packaging material, characterized in that: The raw materials include the following by weight: 90 to 110 parts of polylactic acid, 50 to 70 parts of plasticizer, and 10 to 18 parts of nano titanium dioxide loaded with high tannic acid; The preparation method of high tannic acid loaded nano titanium dioxide is as follows: amino modified mesoporous nano titanium dioxide and tannic acid are mixed in a solvent at a mass ratio of 10:3-18, and loaded to obtain high tannic acid loaded nano titanium dioxide.

2. The high tannic acid loaded nano titanium dioxide antibacterial packaging material according to claim 1, characterized in that: The preparation method of the amino-modified mesoporous nano-titanium dioxide is to disperse the mesoporous nano-titanium dioxide in methanol, add carbonamide and histidine, and react to obtain the amino-modified mesoporous nano-titanium dioxide.

3. The high tannic acid loaded nano titanium dioxide antibacterial packaging material according to claim 2, characterized in that: The mass ratio of the mesoporous nano titanium dioxide, carbonamide and histidine is 15:9 to 13:

5.

4. The high tannic acid loaded nano titanium dioxide antibacterial packaging material according to claim 3, characterized in that: The reaction temperature is 60-85°C.

5. The high tannic acid loaded nano titanium dioxide antibacterial packaging material according to claim 1, characterized in that: The plasticizer is a mixture of polyethylene glycol and glycerol in a mass ratio of 2 to 10:

1.

6. The high tannic acid loaded nano titanium dioxide antibacterial packaging material according to claim 5, characterized in that: The load temperature is 55-65°C.

7. The high tannic acid loaded nano titanium dioxide antibacterial packaging material according to claim 6, characterized in that: The solvent is ethanol.

8. A method for preparing a high-tannic acid loaded nano-titanium dioxide antibacterial packaging material according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) Taking materials by weight, dissolving polylactic acid in dichloromethane, adding plasticizer, and reacting; (2) After the reaction is completed, add high tannic acid loaded nano titanium dioxide and stir to disperse. Ultrasonic degassing, coating and film making are used to obtain nano-titanium dioxide antibacterial packaging materials with high tannic acid loading.

9. The method for preparing the high tannic acid loaded nano titanium dioxide antibacterial packaging material according to claim 8, characterized in that: The reaction temperature is 40-60°C.

10. Use of the high tannic acid loaded nano titanium dioxide antibacterial packaging material according to any one of claims 1 to 7, characterized in that: Used for preserving livestock and poultry meat.

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