Water-retaining antibacterial preservative film and preparation method thereof

Abstract

The application discloses a kind of water-locking antibacterial preservative films and preparation methods thereof, it is related to preservative film technical field, and its technical scheme main points are as follows: including base layer one, base layer two, inner layer and outer layer, the thickness of base layer one and base layer two is identical, its thickness is 5-7 μm, the thickness of inner layer is 4-6 μm, preservative film includes the following weight parts raw materials: low-density PE plastic 40-45 parts, low-density linear PE plastic 40-45 parts, food-grade mica powder 6-8 parts, food-grade talc powder 5-10 parts, metal oxide 2-4 parts, coupling agent 0.5-1 part, carrageenan 1-2 parts, the substrate part of the application only has two kinds of PE plastic and coupling agent, and PE plastic cannot be processed due to more filler content;Meanwhile, outer layer contains metal oxide, which can kill bacteria after combining with food, achieving strong antibacterial effect;And carrageenan and talc powder on the outer layer also improve the water retention performance of food after combining with food, prolong the preservation time.

Description

Technical Field

[0001] This invention relates to the field of food preservation film technology, and in particular to a water-locking and antibacterial food preservation film and its preparation method. Background Technology

[0002] Plastic wrap is a type of plastic packaging product, usually made from ethylene through a polymerization reaction. Plastic wrap can be divided into three main categories: the first is polyethylene, abbreviated as PE; the second is polyvinyl chloride, abbreviated as PVC; and the third is polyvinylidene chloride, abbreviated as PVDC.

[0003] Referring to Chinese invention patent publication number CN108424579B, a food preservation film and its preparation method are disclosed. The technical solution is: a food preservation film, which is made from the following raw materials in parts by weight: 90-99 parts of high molecular polymer base material, 1-5 parts of visible light responsive photocatalyst catalyst and 1-5 parts of chitosan loaded with honeysuckle extract and tangerine peel extract.

[0004] The preservation film provided by the present invention has a long antibacterial and preservation time, and can inhibit the growth of various bacteria and fungi. This preservation film is especially suitable for food preservation in refrigerators, and it has an adaptive and long-lasting preservation effect against air flow and the entry of bacteria caused by opening and closing the refrigerator door. The raw materials for preparing the preservation film are readily available, have high biosafety, and are green and healthy. The preparation process is simple, low in cost, and easy to industrialize. However, it still has some drawbacks, such as: 1. The filler content in the preservation film can exceed 15% at its highest. During the production process, the excessive filler content can make the molten polymer base material difficult to flow, which in turn affects the PE plastic blowing and film formation, thus affecting the overall quality of the preservation film; 2. In this preservation film, the effective bactericidal components are all integrated with the preservation film and do not easily combine with food, resulting in poor bactericidal effect. Summary of the Invention

[0005] In view of the problems mentioned in the background art, the purpose of this invention is to provide a water-locking antibacterial preservation film and its preparation method, so as to solve the problems mentioned in the background art.

[0006] The purpose of this invention is to provide a water-locking and antibacterial food preservation film, comprising a base layer one, a base layer two, an inner layer, and an outer layer. Base layer one and base layer two are connected by the inner layer, and the outer layer is located on the opposite side of base layer one and base layer two. The inner layer is formed after the inner layer coating gels. The water-locking and antibacterial food preservation film comprises the following raw materials in parts by weight:

[0007] 40-45 parts low-density PE plastic, 40-45 parts low-density linear PE plastic, 6-8 parts food-grade mica powder, 5-10 parts food-grade talc powder, 2-4 parts metal oxide, 0.5-1 part coupling agent, and 1-2 parts carrageenan.

[0008] Furthermore, the first and second base layers have the same thickness, which is 5-7 μm, and the inner layer has a thickness of 4-6 μm.

[0009] Furthermore, the metal oxide is food-grade magnesium oxide.

[0010] Furthermore, the grinding particle size of the food-grade mica powder is 200-500 mesh.

[0011] A method for preparing a water-locking and antibacterial food preservation film includes the following steps:

[0012] S1: Add food-grade mica powder and food-grade talc powder to a calcining furnace for calcination, and cool them after calcination for later use.

[0013] S2: Heat and stir the two PE plastics until they are completely melted. After they are completely melted, add the coupling agent, stir evenly, and then perform vacuum degassing.

[0014] S3: The product of S2 is blown into a film, cooled after film formation and subjected to corona treatment to produce base layer one and base layer two.

[0015] S4: Add carrageenan to water and stir until uniform, while continuously heating to obtain a carrageenan solution. Take half of the carrageenan solution and add calcined mica powder and stir until uniform to obtain the inner coating. Take the remaining carrageenan solution and add metal oxide and stir until uniform to obtain the outer coating.

[0016] S5: The inner layer coating is applied to one side of base layer 1 and base layer 2 by spraying.

[0017] S6: After the spraying is completed, the base layer 1 and base layer 2 are bonded together, and the excess inner layer coating is squeezed out by the pressure roller;

[0018] S7: After extrusion, spray the outer coating onto the opposite side of base layer 1 and base layer 2, and cool the gel after spraying.

[0019] S8: Add calcined food-grade talc to the outer layer to obtain a water-locking and antibacterial preservation film.

[0020] Furthermore, in step S1, the temperature inside the food-grade mica powder furnace is 700-800℃, the temperature inside the food-grade talc powder furnace is 1000-1100℃, and the calcination time is 40-60 minutes.

[0021] Furthermore, the vacuum degassing process in step S2 takes 20-30 minutes.

[0022] Furthermore, in step S4, the continuous heating temperature is 80-90℃, and the concentration of the resulting carrageenan solution is 1-1.5%.

[0023] Furthermore, the cooling time for the gel in step S7 is 10-20 minutes.

[0024] In summary, the present invention has the following main advantages:

[0025] I. In this invention, the matrix one and matrix two only contain three materials: two types of PE plastics and a coupling agent. When using the food preservation film made by this invention, the content of fillers is lower than that of the prior art when producing the matrix one and matrix two. In addition to PE plastics, it only contains a coupling agent for improving stability, and the content of the coupling agent does not exceed 1.1% of the total mass. There will be no situation where the PE plastic is difficult to process due to a large amount of fillers, which is conducive to ensuring the overall quality of the food preservation film.

[0026] Second, in this invention, since the outer layer contains food-grade magnesium oxide, during use, part of the outer layer will fall off. The fallen magnesium oxide mixes with food, and the magnesium oxide generates peroxide ions through redox reactions. Peroxide ions can destroy the protein peptide chains of bacterial cell membrane walls, leading to microbial lysis and apoptosis. At the same time, the surface of magnesium oxide contains active sites that can adsorb with bacteria, causing cell deformation, lysis and death, further enhancing the sterilization effect.

[0027] Thirdly, in this invention, the inner layer also contains mica powder, and the outer layer also contains talc powder, with a far-infrared emissivity greater than 0.92. Since vegetables and fruits are 70%-95% water, and meat has a water content of over 60%, the far-infrared rays released by the mica powder and talc powder activate the water molecules in vegetables, fruits, and meat, thereby extending the freshness of the food, significantly reducing the rate of food deterioration, and achieving long-term food preservation. In addition, the outer layer of the preservation contains talc powder and carrageenan, which have water-retaining properties and can be used as water-retaining agents. When the side with the outer layer is wrapped around the food, the carrageenan and talc powder on the outer layer can combine with the food, improving the water-retaining and water-locking properties of the food. This invention ensures that when food is preserved for a long time, the food will not lose a lot of water, resulting in a decrease in taste. Attached Figure Description

[0028] Figure 1 This is a comparative schematic diagram showing the preservation of fish meat using a comparative example of a plastic wrap (left) and a plastic wrap prepared according to the present invention (right).

[0029] Figure 2 A comparative schematic diagram showing the preservation of meat using a comparative example of a plastic wrap (left) and a plastic wrap prepared according to the present invention (right);

[0030] Figure 3 A comparative schematic diagram showing the preservation of bread using a comparative example of plastic wrap (left) and the plastic wrap prepared according to the present invention (right);

[0031] Figure 4 This is a process flow diagram of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment provides a water-locking and antibacterial food preservation film, comprising a base layer one, a base layer two, an inner layer, and an outer layer. Base layer one and base layer two are connected by the inner layer, and the outer layer is located on the opposite side of base layer one and base layer two. The inner layer is formed after the inner layer coating gels. The above-mentioned food preservation film comprises the following raw materials in parts by weight:

[0035] The composition includes 40 parts low-density PE plastic, 40 parts low-density linear PE plastic, 6 parts food-grade mica powder, 50 parts food-grade talc powder, 2 parts metal oxide, 0.5 parts coupling agent, and 1 part carrageenan. The metal oxide is food-grade magnesium oxide, and the grinding particle size of the food-grade mica powder is 200 mesh. Among them, the low-density PE plastic is produced by Shanghai Bangdaer Plastics Co., Ltd., with the grade 1C7A; the low-density linear PE plastic is produced by Dongguan Yuxin Plastics Co., Ltd., with the grade DFDA-7042; the food-grade mica powder is silver-white mica powder produced by Jiangsu Liduo New Technology Co., Ltd.; the food-grade talc powder is produced by Zhengzhou Xigui Chemical Co., Ltd.; and the food-grade magnesium oxide is produced by Shijiazhuang Tianyu Magnesium Industry Co., Ltd.

[0036] The above-mentioned method for making plastic wrap includes the following steps:

[0037] S1: Add food-grade mica powder and food-grade talc powder to a calcining furnace and calcine for 40 minutes. The furnace temperature for food-grade mica powder is 700℃ and the furnace temperature for food-grade talc powder is 1000℃. After calcination, cool and set aside.

[0038] S2: Heat and stir the two PE plastics until they are completely melted. After they are completely melted, add the coupling agent, stir evenly, and then perform vacuum degassing treatment for 20 minutes.

[0039] S3: The product of S2 is blown into a film with a thickness of 5μm. After film formation, it is cooled and subjected to corona treatment to produce base layer one and base layer two.

[0040] S4: Add carrageenan to water and stir until uniform, while continuously heating to obtain a carrageenan solution. Take half of the carrageenan solution and add calcined mica powder and stir until uniform to obtain the inner coating. Take the remaining carrageenan solution and add metal oxide and stir until uniform to obtain the outer coating.

[0041] S5: The inner layer coating is applied to one side of base layer 1 and base layer 2 by spraying.

[0042] S6: After the spraying is completed, the base layer 1 and base layer 2 are bonded together, and the excess inner layer coating is squeezed out by the pressure roller;

[0043] S7: After extrusion, the total thickness is 14μm. Spray the outer coating onto the opposite side of base layer 1 and base layer 2. After spraying, cool the gel for 10 minutes.

[0044] S8: Add calcined food-grade talc to the outer layer to obtain a water-locking and antibacterial preservation film.

[0045] Example 2

[0046] Unlike Example 1, the plastic wrap provided in this example comprises the following raw materials in parts by weight:

[0047] 42.5 parts low-density PE plastic, 42.5 parts low-density linear PE plastic, 7 parts food-grade mica powder, 7.5 parts food-grade talc powder, 3 parts metal oxide, 0.75 parts coupling agent, 1.5 parts carrageenan, the metal oxide is food-grade magnesium oxide, and the grinding particle size of the food-grade mica powder is 350 mesh.

[0048] The above-mentioned method for making plastic wrap includes the following steps:

[0049] S1: Add food-grade mica powder and food-grade talc powder to a calcining furnace and calcine for 50 minutes. The furnace temperature for food-grade mica powder is 750℃ and the furnace temperature for food-grade talc powder is 1050℃. After calcination, cool and set aside.

[0050] S2: Heat and stir the two PE plastics until they are completely melted. After they are completely melted, add the coupling agent, stir evenly, and then perform vacuum degassing.

[0051] S3: The product of S2 is blown into a film with a thickness of 6μm. After film formation, it is cooled and subjected to corona treatment to produce base layer one and base layer two.

[0052] S4: Add carrageenan to water and stir evenly, continuously heating to 85°C to obtain a carrageenan solution with a concentration of 1.25%. Take half of the carrageenan solution, add calcined mica powder and stir evenly to obtain the inner coating. Take the remaining carrageenan solution, add metal oxide and stir evenly to obtain the outer coating.

[0053] S5: The inner layer coating is applied to one side of base layer 1 and base layer 2 by spraying.

[0054] S6: After the spraying is completed, the base layer 1 and base layer 2 are bonded together, and the excess inner layer coating is squeezed out by the pressure roller;

[0055] S7: After extrusion, the total thickness is 17μm. Spray the outer coating onto the opposite side of base layer 1 and base layer 2. After spraying, cool the gel for 15 minutes.

[0056] S8: Add calcined food-grade talc to the outer layer to obtain a water-locking and antibacterial preservation film.

[0057] Example 3

[0058] Unlike Example 2, the cling film provided in this example comprises the following raw materials in parts by weight:

[0059] 45 parts low-density PE plastic, 45 parts low-density linear PE plastic, 8 parts food-grade mica powder, 10 parts food-grade talc powder, 4 parts metal oxide, 1 part coupling agent, 2 parts carrageenan, the metal oxide is food-grade magnesium oxide, and the grinding particle size of the food-grade mica powder is 500 mesh.

[0060] The above-mentioned method for making plastic wrap includes the following steps:

[0061] S1: Add food-grade mica powder and food-grade talc powder to a calcining furnace and calcine for 60 minutes. The furnace temperature for food-grade mica powder is 800℃ and the furnace temperature for food-grade talc powder is 1100℃. After calcination, cool and set aside.

[0062] S2: Heat and stir the two PE plastics until they are completely melted. After they are completely melted, add the coupling agent, stir evenly, and then perform vacuum degassing.

[0063] S3: The product of S2 is blown into a film with a thickness of 7μm. After film formation, it is cooled and subjected to corona treatment to produce base layer one and base layer two.

[0064] S4: Add carrageenan to water and stir evenly, while continuously heating to 90°C to obtain a carrageenan solution with a concentration of 1.5%. Take half of the carrageenan solution, add calcined mica powder and stir evenly to obtain the inner coating. Take the remaining carrageenan solution, add metal oxide and stir evenly to obtain the outer coating.

[0065] S5: The inner layer coating is applied to one side of base layer 1 and base layer 2 by spraying.

[0066] S6: After the spraying is completed, the base layer 1 and base layer 2 are bonded together, and the excess inner layer coating is squeezed out by the pressure roller;

[0067] S7: After extrusion, the total thickness is 20μm. Spray the outer coating onto the opposite side of base layer 1 and base layer 2. After spraying, cool the gel for 20 minutes.

[0068] S8: Add calcined food-grade talc to the outer layer to obtain a water-locking and antibacterial preservation film.

[0069] The performance of the prepared plastic wrap was tested as follows: different foods were stored for 7 days under the same temperature and humidity conditions using Examples 1, 2, 3 and conventional plastic wrap (comparative example). The test results are shown in the table below:

[0070] Table 1

[0071]

[0072]

[0073] Using Examples 1, 2, and 3, the water loss rates when storing spinach were 8.1%, 9.4%, and 8%, respectively, with an average water loss rate of 8.5%. When storing longan, the water loss rates were 1.15%, 1.32%, and 2.51%, respectively, with an average water loss rate of 1.66%. When storing peaches, the water loss rates were 0.7%, 1.42%, and 1.22%, respectively, with an average water loss rate of 1.11%. When storing cherries, the water loss rates were 1.29%, 1.91%, and 1.7%, respectively, with an average water loss rate of 1.63%. In contrast, conventional plastic wrap resulted in water loss rates of 38.3%, 9.45%, 1.94%, and 5.23% when storing these four foods, all significantly higher than the plastic wrap made using this invention.

[0074] refer to Figures 1-3 , Figures 1-3 In both cases, the storage environment was the same. The left image shows storage using the comparative example plastic wrap, while the right image shows storage using the plastic wrap prepared in Example 1. Figure 1 The initial weight of the fish meat was 100g. The water loss in the left image was 4.79g, and the water loss in the right image was 0.17g. Figure 2 The meat in the middle is placed on top of an iron ball to test its elasticity. As you can see in the left image, the meat has lost its elasticity, and the middle section has collapsed under the weight of the iron ball. The meat on the right, however, did not collapse, and its elasticity remains good. Figure 3 In the left image, the bread slice has become moldy, with mold spots forming in the middle, while the bread slice in the right image is relatively well preserved. This shows that the preservation, water-locking, and sterilization effects of the present invention are better than those of the comparative plastic wrap.

[0075] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it; although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A water-locking and antibacterial food preservation film, characterized in that: The film comprises a base layer 1, a base layer 2, an inner layer, and an outer layer. Base layer 1 and base layer 2 are connected by the inner layer. The outer layer is located on the opposite side of base layer 1 and base layer 2. The inner layer is formed after the inner layer coating gels. The water-locking and antibacterial food preservation film comprises the following raw materials in parts by weight: 40-45 parts of low-density PE plastic, 40-45 parts of low-density linear PE plastic, 6-8 parts of food-grade mica powder, 5-10 parts of food-grade talc powder, 2-4 parts of metal oxide, 0.5-1 part of coupling agent, 1-2 parts of carrageenan, wherein the metal oxide is food-grade magnesium oxide. The raw materials for base layer one and base layer two are composed of low-density PE plastic, low-density linear PE plastic and coupling agent. The raw materials for the inner layer are composed of carrageenan and food-grade mica powder. The raw materials for the outer layer are composed of carrageenan, food-grade talc powder and food-grade magnesium oxide. The grinding particle size of the food-grade mica powder is 200-500 mesh.

2. The water-locking and antibacterial food preservation film according to claim 1, characterized in that: The first and second base layers have the same thickness, which is 5-7 μm, while the inner layer has a thickness of 4-6 μm.

3. A method for preparing a water-locking and antibacterial food preservation film as described in any one of claims 1-2, characterized in that, Includes the following steps: S1: Add food-grade mica powder and food-grade talc powder to a calcining furnace for calcination, and cool them after calcination for later use. S2: Heat and stir the two PE plastics until they are completely melted. After they are completely melted, add the coupling agent, stir evenly, and then perform vacuum degassing. S3: The product of S2 is blown into a film, cooled after film formation and subjected to corona treatment to produce base layer one and base layer two. S4: Add carrageenan to water and stir until uniform, while continuously heating to obtain a carrageenan solution. Take half of the carrageenan solution and add calcined mica powder and stir until uniform to obtain the inner coating. Take the remaining carrageenan solution and add metal oxide and stir until uniform to obtain the outer coating. S5: The inner layer coating is applied to one side of base layer 1 and base layer 2 by spraying. S6: After the spraying is completed, the base layer 1 and base layer 2 are bonded together, and the excess inner layer coating is squeezed out by the pressure roller; S7: After extrusion, spray the outer coating onto the opposite side of base layer 1 and base layer 2, and cool the gel after spraying. S8: Add calcined food-grade talc to the outer layer to obtain a water-locking and antibacterial preservation film.

4. The method for preparing a water-locking and antibacterial preservation film according to claim 3, characterized in that: In step S1, the temperature inside the furnace for food-grade mica powder is 700-800℃, the temperature inside the furnace for food-grade talc powder is 1000-1100℃, and the calcination time is 40-60 minutes.

5. The method for preparing a water-locking and antibacterial preservation film according to claim 3, characterized in that: The vacuum degassing process in step S2 takes 20-30 minutes.

6. The method for preparing a water-locking and antibacterial preservation film according to claim 3, characterized in that: In step S4, the heating temperature is continuously maintained at 80-90℃, and the concentration of the resulting carrageenan solution is 1-1.5%.

7. The method for preparing a water-locking and antibacterial food preservation film according to claim 3, characterized in that: The cooling time for the gel in step S7 is 10-20 minutes.

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