A novel antiseptic and antibacterial fresh-keeping film and preparation method thereof

Abstract

The present invention relates to a novel antiseptic and antibacterial cling film and a preparation method thereof, and belongs to the technical field of food preservation. The novel antiseptic and antibacterial cling film of the present invention comprises the following components: 100-120 parts by weight of polyvinyl alcohol, 15-20 parts by weight of phosphorylated polysaccharide, 10-15 parts by weight of prickly ash essential oil, 5-10 parts by weight of ginger essential oil, 20-30 parts by weight of chitosan, 5-8 parts by weight of plasticizer, and 1800-2000 parts by weight of distilled water. The antiseptic and antibacterial cling film provided by the present invention can effectively extend the storage period of fruits, vegetables, meat products and other foods.

Description

Technical Field

[0001] The invention belongs to the technical field of food preservation, and relates to a novel antiseptic and antibacterial fresh-keeping film and a preparation method thereof. Background Art

[0002] Cling film is a plastic packaging product, usually made by polymerization reaction with ethylene as the masterbatch. Cling film can be divided into three categories: the first is polyethylene, referred to as PE; the second is polyvinyl chloride, referred to as PVC; the third is polyvinylidene chloride, referred to as PVDC. As human beings pay more attention to the environment and the quality requirements for food, medicine, daily necessities, etc. increase, all walks of life have higher standards for various plastic packaging, hoping to be friendly to the ecological environment on the basis of excellent performance.

[0003] Biodegradable plastics, also known as biodegradable plastics, refer to plastics that are degraded by microorganisms in nature under natural conditions such as soil and / or sand, and / or specific conditions such as composting conditions or anaerobic digestion conditions or aqueous culture medium, and are eventually completely degraded into carbon dioxide (CO2) and / or methane (CH4), water (H2O) and mineralized inorganic salts of the elements they contain, as well as new biomass. Biodegradable plastics are mainly used as soft and hard food packaging materials due to their good degradability, which is also their largest application area at this stage. In the future, it has become an inevitable trend to use new pollution-free biodegradable plastic cling film to replace traditional plastic cling film.

[0004] Polysaccharides are a class of natural high molecular compounds, which are polymers of aldose or ketose linked by glycosidic bonds. They exist in higher plants, algae, fungi and animals, and are the most abundant biopolymers in nature. Polysaccharides have a wide range of pharmacological effects, such as enhancing immunity, anti-tumor, anti-virus, lowering blood sugar, protecting gastrointestinal function, etc., and are one of the hot areas of health care products and drug research and development. At the same time, due to the special physical and chemical properties of polysaccharides, they are also widely used in the food industry. The Chinese invention patent "A kind of water chestnut polysaccharide composite cling film and its preparation method", application number CN202211273170.8, discloses that corn starch is used as the main film-forming material and water chestnut polysaccharide is used to prepare the cling film by casting method. The water chestnut polysaccharide composite cling film has high hydrophobic antioxidant properties, and good fresh-keeping performance and mechanical properties. It has good application prospects in berry preservation. In addition, structural modification can change the molecular weight, substitution group type and molecular structure of polysaccharides, thereby affecting the biological activity of polysaccharides. The Chinese invention patent "A method for preparing a modified polysaccharide cling film", application number CN201711169906.6, discloses a cling film prepared using modified pullulan as raw material. The cling film has high water and oxygen barrier properties, and at the same time has good freshness preservation and mechanical properties, and has good application prospects in fruit and vegetable preservation.

[0005] Up to now, there is no relevant literature reporting the application of phosphorylated-modified polysaccharides in plastic wrap. Summary of the invention

[0006] The main purpose of the present invention is to provide a novel antiseptic and antibacterial fresh-keeping film and a preparation method thereof, the antiseptic and antibacterial fresh-keeping film.

[0007] The present invention adopts the following technical solutions to achieve the above purpose:

[0008] A novel antiseptic and antibacterial fresh-keeping film comprises the following components:

[0009]

[0010] Wherein, the preparation method of the phosphorylated polysaccharide is:

[0011] S1, adding sodium sulfate to the complex polysaccharide solution containing chicory polysaccharide and trehalose, and then adding a phosphorylation reagent, adjusting the pH of the solution to 7-8, reacting at 70-80° C. for 3-5 hours, and cooling to room temperature to obtain a semi-finished product solution;

[0012] S2, adding 95% ethanol solution to the finished product solution, standing and precipitating, taking the precipitate, removing the residual ethanol, re-dissolving, purifying by gel column, and drying to obtain phosphorylated polysaccharide.

[0013] Furthermore, in the phosphorylated polysaccharide preparation method S1, the mass ratio of chicory polysaccharide, trehalose, sodium sulfate, and phosphorylation reagent is (2-3):(1-2):(15-20):(25-30).

[0014] Furthermore, in the phosphorylated polysaccharide preparation method S1, the phosphorylation reagent is a mixture of sodium tripolyphosphate, sodium trimetaphosphate, and disodium hydrogen phosphate.

[0015] Furthermore, the mass ratio of sodium tripolyphosphate, sodium trimetaphosphate and disodium hydrogen phosphate in the phosphorylation reagent is (1-2):(1-3):(0.5-1).

[0016] Furthermore, the plasticizer in the novel antiseptic and antibacterial cling film is one or more of glycerol, glyceryl monostearate, and dioctyl phthalate.

[0017] The present invention provides a method for preparing the novel antiseptic and antibacterial cling film, which specifically comprises the following steps:

[0018] Add polyvinyl alcohol and chitosan into water to dissolve to obtain a film-forming solution; heat the film-forming solution to 80-100°C, add phosphorylated polysaccharide and plasticizer, and stir for 20-40 minutes; cool to room temperature, add pepper essential oil and ginger essential oil, ultrasonicate and stir at 20-30°C for 20-30 minutes to obtain a film-forming emulsion; electrospin the film-forming emulsion to obtain a spinning film, and then dry the spinning film to obtain a new antiseptic and antibacterial cling film.

[0019] Furthermore, the parameters of the electrospinning are: spinning voltage is 18-20KV, spinning speed is 1-1.2mL / h, and receiving distance is 12-15cm.

[0020] The present invention provides a specific application of the novel antiseptic and antibacterial fresh-keeping film, that is, the film can be used for preserving fruits, vegetables, meat and other foods.

[0021] The present invention has the following beneficial effects:

[0022] 1. The addition of phosphorylated chicory polysaccharide and phosphorylated trehalose in the fresh-keeping film prepared by the present invention can improve its strength and air permeability, and make it have a certain hygroscopicity, and can effectively absorb moisture generated by respiration in various fruits, vegetables and other foods, so that the absorbed moisture can form a uniform water film on the surface of the fresh-keeping film to isolate external microorganisms. At the same time, it also has good air permeability, has good internal humidity regulation and external air permeability performance, and prolongs the shelf life of fruits and vegetables.

[0023] 2. The present invention adopts chitosan, phosphorylated chicory polysaccharide, phosphorylated trehalose and other ingredients to prepare the cling film. The presence of these ingredients makes the cling film have good mechanical properties and tensile strength, is safe and non-toxic, does not cause harm to the human body, and is a natural ingredient with excellent degradable properties.

[0024] 3. The cling film provided by the present invention uses pepper essential oil and ginger essential oil with antibacterial effects as antibacterial agents, which can effectively inhibit the growth of common microorganisms in food and extend the preservation period of food. The natural biological antibacterial agents provide a guarantee for food safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Attached Figure 1 : Comparison of strawberry hardness changes;

[0026] Attached Figure 2 : Comparison of weight loss rate of strawberry. DETAILED DESCRIPTION

[0027] The present invention is further explained below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent modifications to the present invention by those skilled in the art all fall within the scope of protection of the claims of this application.

[0028] Example 1

[0029] Preparation of phosphorylated polysaccharide:

[0030] S1, add 2g of chicory polysaccharide and 1g of trehalose to 100mL of water, stir and dissolve at 50°C, and cool to room temperature to obtain a composite polysaccharide solution; add 15g of sodium sulfate to the composite polysaccharide solution, stir evenly, add a phosphorylation reagent containing 10g of sodium tripolyphosphate, 10g of sodium trimetaphosphate, and 5g of disodium hydrogen phosphate, and adjust the solution pH to 7 with NaHCO3, react at 80°C for 3h, and cool to room temperature to obtain a semi-finished product solution;

[0031] S2, add 3 times the volume of 95% ethanol solution to the finished product solution, let it stand for 24 hours, centrifuge, take the precipitate, remove the residual ethanol, freeze-dry, re-dissolve with water in a 60°C water bath, purify with Sephadex G-25 gel column, freeze-dry, and obtain phosphorylated polysaccharide.

[0032] Preparation of new antiseptic and antibacterial cling film:

[0033] 120g of polyvinyl alcohol and 20g of chitosan are added to 2000mL of water to dissolve (heating can be appropriately used to promote dissolution) to obtain a film-forming solution; the film-forming solution is heated to 100°C, 15g of the phosphorylated polysaccharide obtained according to the above method and 30g of glyceryl monostearate are added, and the mixture is stirred for 20min; the film-forming solution is cooled to room temperature, 15g of prickly ash essential oil and 5g of ginger essential oil are added, and the mixture is ultrasonically stirred at 20°C for 30min to obtain a film-forming emulsion; the film-forming emulsion is subjected to electrostatic spinning to obtain a spinning film, and the spinning film is then dried in a drying oven at 35°C to obtain a new antiseptic and antibacterial cling film having a thickness of 0.053mm.

[0034] The electrospinning parameters are as follows: spinning voltage is 20 KV, spinning speed is 1.2 mL / h, and receiving distance is 15 cm.

[0035] Example 2

[0036] Preparation of phosphorylated polysaccharide:

[0037] S1, add 3g of chicory polysaccharide and 2g of trehalose to 120mL of water, stir and dissolve at 50°C, and cool to room temperature to obtain a composite polysaccharide solution; add 20g of sodium sulfate to the composite polysaccharide solution, stir evenly, add a phosphorylation reagent containing 10g of sodium tripolyphosphate, 15g of sodium trimetaphosphate, and 5g of disodium hydrogen phosphate, and adjust the solution pH to 7 with NaHCO3, react at 80°C for 3h, and cool to room temperature to obtain a semi-finished product solution;

[0038] S2, add 3 times the volume of 95% ethanol solution to the finished product solution, let it stand for 24 hours, centrifuge, take the precipitate, remove the residual ethanol, freeze-dry, re-dissolve with water in a 60°C water bath, purify with Sephadex G-25 gel column, freeze-dry, and obtain phosphorylated polysaccharide.

[0039] Preparation of new antiseptic and antibacterial cling film:

[0040] 100g of polyvinyl alcohol and 30g of chitosan were added into 1800mL of water to dissolve (heating can be appropriately used to promote dissolution) to obtain a film-forming solution; the film-forming solution was heated to 80°C, 20g of phosphorylated polysaccharide and 20g of glycerol obtained according to the above method were added, and stirred for 40min; the film-forming solution was cooled to room temperature, and 10g of prickly ash essential oil and 10g of ginger essential oil were added, and ultrasonicated and stirred at 30°C for 20min to obtain a film-forming emulsion; the film-forming emulsion was electrospun to obtain a spinning film, and the spinning film was then dried in a drying oven at 35°C to obtain a new antiseptic and antibacterial cling film with a thickness of 0.056mm.

[0041] The electrospinning parameters are as follows: spinning voltage is 18KV, spinning speed is 1mL / h, and receiving distance is 12cm.

[0042] Example 3

[0043] Preparation of phosphorylated polysaccharide:

[0044] S1, add 3g of chicory polysaccharide and 1g of trehalose to 100mL of water, stir and dissolve at 50°C, and cool to room temperature to obtain a composite polysaccharide solution; add 18g of sodium sulfate to the composite polysaccharide solution, stir evenly, add a phosphorylation reagent containing 9g of sodium tripolyphosphate, 9g of sodium trimetaphosphate, and 9g of disodium hydrogen phosphate, and adjust the solution pH to 7 with NaHCO3, react at 80°C for 3h, and cool to room temperature to obtain a semi-finished product solution;

[0045] S2, add 3 times the volume of 95% ethanol solution to the finished product solution, let it stand for 24 hours, centrifuge, take the precipitate, remove the residual ethanol, freeze-dry, re-dissolve with water in a 60°C water bath, purify with Sephadex G-25 gel column, freeze-dry, and obtain phosphorylated polysaccharide.

[0046] Preparation of new antiseptic and antibacterial cling film:

[0047] 110g of polyvinyl alcohol and 25g of chitosan are added to 2000mL of water to dissolve (heating can be appropriately used to promote dissolution) to obtain a film-forming solution; the film-forming solution is heated to 90°C, 18g of the phosphorylated polysaccharide obtained according to the above method and 25g of glyceryl monostearate are added, and the mixture is stirred for 30min; the film-forming solution is cooled to room temperature, 13g of prickly ash essential oil and 8g of ginger essential oil are added, and the mixture is ultrasonically treated and stirred at 30°C for 25min to obtain a film-forming emulsion; the film-forming emulsion is subjected to electrostatic spinning to obtain a spinning film, and the spinning film is then dried in a drying oven at 35°C to obtain a new antiseptic and antibacterial cling film having a thickness of 0.061mm.

[0048] The electrospinning parameters are as follows: spinning voltage is 20 KV, spinning speed is 1 mL / h, and receiving distance is 13 cm.

[0049] Comparative Example 1

[0050] Preparation of new antiseptic and antibacterial cling film:

[0051] Add 120g of polyvinyl alcohol and 20g of chitosan into 2000mL of water to dissolve (heating can be appropriately used to promote dissolution) to obtain a film-forming solution; heat the film-forming solution to 100°C, add 10g of chicory polysaccharide, 10g of trehalose, and 30g of glyceryl monostearate, and stir for 20 minutes; cool to room temperature, add 15g of prickly ash essential oil and 5g of ginger essential oil, ultrasonically stir at 20°C for 30 minutes to obtain a film-forming emulsion; electrospin the film-forming emulsion to obtain a spinning film, and then place the spinning film in a 35°C drying oven to dry to obtain a preservative film with a thickness of 0.055mm.

[0052] The electrospinning parameters are as follows: spinning voltage is 20 KV, spinning speed is 1.2 mL / h, and receiving distance is 15 cm.

[0053] Comparative Example 2

[0054] Preparation of phosphorylated polysaccharide:

[0055] S1, add 2g of chicory polysaccharide to 100mL of water, stir and dissolve at 50℃, and cool to room temperature to obtain a polysaccharide solution; add 15g of sodium sulfate to the polysaccharide solution, stir evenly, add a phosphorylation reagent containing 10g of sodium tripolyphosphate and 10g of sodium trimetaphosphate, and adjust the solution pH to 7 with NaHCO3, react at 80℃ for 3h, and cool to room temperature to obtain a semi-finished product solution;

[0056] S2, add 3 times the volume of 95% ethanol solution to the finished product solution, let it stand for 24 hours, centrifuge, take the precipitate, remove the residual ethanol, freeze-dry, re-dissolve with water in a 60°C water bath, purify with Sephadex G-25 gel column, freeze-dry, and obtain phosphorylated polysaccharide.

[0057] Preparation of new antiseptic and antibacterial cling film:

[0058] 120g of polyvinyl alcohol was added to 2000mL of water to dissolve (heating can be appropriately used to promote dissolution) to obtain a film-forming solution; the film-forming solution was heated to 100°C, 15g of the phosphorylated polysaccharide obtained according to the above method and 30g of glyceryl monostearate were added, and stirred for 20 minutes; the film-forming solution was cooled to room temperature, and 15g of prickly ash essential oil and 5g of ginger essential oil were added, and ultrasonicated and stirred at 20°C for 30 minutes to obtain a film-forming emulsion; the film-forming emulsion was subjected to electrostatic spinning to obtain a spinning film, and the spinning film was then placed in a drying oven at 35°C to dry to obtain a cling film, and the thickness of the cling film was 0.059mm.

[0059] The electrospinning parameters are as follows: spinning voltage is 20 KV, spinning speed is 1.2 mL / h, and receiving distance is 15 cm.

[0060] Comparative Example 3

[0061] Preparation of phosphorylated polysaccharide:

[0062] S1, add 1g of trehalose to 100mL of water, stir and dissolve at 50℃, cool to room temperature to obtain a composite polysaccharide solution; add 15g of sodium sulfate to the composite polysaccharide solution, stir evenly, add a phosphorylation reagent containing 10g of sodium tripolyphosphate, 10g of sodium trimetaphosphate, and 5g of disodium hydrogen phosphate, and adjust the pH of the solution to 7 with NaHCO3, react at 80℃ for 3h, cool to room temperature to obtain a semi-finished product solution;

[0063] S2, add 3 times the volume of 95% ethanol solution to the finished product solution, let it stand for 24 hours, centrifuge, take the precipitate, remove the residual ethanol, freeze-dry, re-dissolve with water in a 60°C water bath, purify with Sephadex G-25 gel column, freeze-dry, and obtain phosphorylated polysaccharide.

[0064] Preparation of new antiseptic and antibacterial cling film:

[0065] 120g of polyvinyl alcohol and 20g of chitosan are added to 2000mL of water to dissolve (heating can be appropriately used to promote dissolution) to obtain a film-forming solution; the film-forming solution is heated to 100°C, 15g of the phosphorylated polysaccharide obtained according to the above method and 30g of glyceryl monostearate are added, and stirred for 20 minutes; cooled to room temperature, 15g of prickly ash essential oil is added, ultrasonicated and stirred at 20°C for 30 minutes to obtain a film-forming emulsion; the film-forming emulsion is subjected to electrostatic spinning to obtain a spinning film, and then the spinning film is placed in a 35°C drying oven to dry to obtain a preservative film, and the thickness of the preservative film is 0.051mm.

[0066] The electrospinning parameters are as follows: spinning voltage is 20 KV, spinning speed is 1.2 mL / h, and receiving distance is 15 cm.

[0067] 1. Mechanical properties test of plastic wrap

[0068] Take the cling film prepared according to the method described in Examples 1-3 and Comparative Examples 1-3, cut the cling film into 5 mm×50 mm, perform a tensile test, record the length and tensile force when the film breaks, repeat 3 times, take the average value, and calculate the tensile strength and elongation at break.

[0069] Table 1 Mechanical properties of various cling films

[0070]

[0071]

[0072] As can be seen from Table 1, the addition of phosphorylated polysaccharide has a great influence on the mechanical properties of the cling film, which can significantly improve the tensile strength and elongation at break of the cling film and increase the toughness of the cling film.

[0073] 2. Determine the air permeability of cling film according to the national standard method

[0074] Table 2 Air permeability of various cling films

[0075]

[0076] From the results in Table 2, it can be seen that the cling films obtained in Examples 1-3 of the present invention have good air permeability.

[0077] 3. Antibacterial performance test of plastic wrap

[0078] 0.3 mL of a bacterial suspension containing Escherichia coli, Staphylococcus aureus and Penicillium was added to a culture dish and spread evenly. Cling film discs with a diameter of 50 mm prepared according to the methods described in Examples 1-3 and Comparative Examples 1-3 were added to the culture dish respectively, and the culture was carried out at a constant temperature of 25° C. in an incubator to observe the antibacterial and antiseptic properties of the cling film.

[0079] Table 3 Antibacterial properties of various cling films

[0080]

[0081]

[0082] As shown in Table 3, the cling films prepared in Examples 1-3 and Comparative Examples 1-2 have good antibacterial properties, and have obvious inhibitory effects on Escherichia coli, Staphylococcus aureus, and Penicillium, completely inhibiting their growth.

[0083] 4. Test of antiseptic properties of plastic wrap

[0084] Ripe "Hongyan" strawberry fresh fruits with substantially the same weight and initial hardness were selected, and after sterilization, they were divided into Experimental Group 1 (cling film of Example 1), Experimental Group 2 (cling film of Example 2), Experimental Group 3 (cling film of Example 3), Experimental Group 4 (cling film of Comparative Example 1), Experimental Group 5 (cling film of Comparative Example 2), Experimental Group 6 (cling film of Comparative Example 3), and Experimental Group 7 (commercially available ordinary cling film), 20 strawberries in each group, respectively covered with a layer of cling film, stored at room temperature, and the strawberries were observed every other day and 2 strawberries were sampled to measure relevant evaluation indicators of strawberries (morphology, color, strawberry hardness, weight loss rate, etc.).

[0085] 4.1 Sensory evaluation

[0086] On the third day, the fruits of group 7 began to mold, softened severely, darkened in color, and had obvious water mist on the inner surface of the plastic wrap;

[0087] In Experiment 6, the fruits began to soften on the 5th day, and became moldy and rotten on the 6th day. The inner surface of the plastic wrap was moist but without water mist.

[0088] The fruits of Experiment 5 group softened on the 5th day, and became moldy and rotten on the 8th day, with a thin mist on the inner surface of the plastic wrap;

[0089] In experimental group 4, the fruit rotted and softened severely on the 5th day, and there was obvious water mist on the inner surface of the plastic wrap;

[0090] The fruits of experimental groups 1-3 did not rot on the 11th day, but softened, became less plump, and darkened slightly in color. There was no mist on the inner surface of the plastic wrap and it was dry.

[0091] 4.2 Hardness determination

[0092] The strawberry hardness of experimental group 7 decreased the most, followed by experimental group 6. The decreasing trends of experimental groups 4 and 5 were basically the same. The decreasing trend of experimental groups 1-3 was the slowest. The results are shown in the attached Figure 1 .

[0093] 4.3 Weight loss rate

[0094] The weight loss rate of strawberries increased with time. The weight loss rate of strawberries in Experimental Groups 1-3 showed a slow trend, while the weight loss rate of Experimental Groups 4 and 7 showed a more obvious trend. The results are shown in the attached Figure 2 .

Claims

1. A novel antiseptic and antibacterial fresh-keeping film, characterized in that: Includes the following components: Wherein, the plasticizer is one or more of glycerol, glyceryl monostearate, and dioctyl phthalate; and the preparation method of the phosphorylated polysaccharide is: S1, adding sodium sulfate to a complex polysaccharide solution containing chicory polysaccharide and trehalose, and then adding a phosphorylation agent, adjusting the pH of the solution to 7-8, reacting at 70-80°C for 3-5h, cooling to room temperature, and obtaining a semi-finished product solution; the mass ratio of the chicory polysaccharide, trehalose, sodium sulfate, and phosphorylation agent is (2-3):(1-2):(15-20):(25-30); the phosphorylation agent is a mixture of sodium tripolyphosphate, sodium trimetaphosphate, and disodium hydrogen phosphate, and the mass ratio of sodium tripolyphosphate, sodium trimetaphosphate, and disodium hydrogen phosphate is (1-2):(1-3):(0.5-1); S2, adding 95% ethanol solution to the semi-finished product solution, standing to precipitate, taking the precipitate, removing the residual ethanol, re-dissolving, purifying by gel column, and drying to obtain phosphorylated polysaccharide; The preparation method of the novel antiseptic and antibacterial fresh-keeping film comprises the following steps: Add polyvinyl alcohol and chitosan into water to dissolve to obtain a film-forming solution; heat the film-forming solution to 80-100°C, add phosphorylated polysaccharide and plasticizer, and stir for 20-40 minutes; cool to room temperature, add pepper essential oil and ginger essential oil, ultrasonicate and stir at 20-30°C for 20-30 minutes to obtain a film-forming emulsion; electrospin the film-forming emulsion to obtain a spinning film, and then dry the spinning film to obtain a new antiseptic and antibacterial cling film.

2. The novel antiseptic and antibacterial fresh-keeping film according to claim 1, characterized in that: The parameters of electrospinning in the preparation method of the novel antiseptic and antibacterial cling film are as follows: spinning voltage is 18-20 KV, spinning speed is 1-1.2 mL / h, and receiving distance is 12-15 cm.

3. A use of the novel antiseptic and antibacterial cling film as claimed in claim 1 or 2, characterized in that: The novel antiseptic and antibacterial fresh-keeping film is used for food preservation.

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