A water-soluble mango peel packaging film and its preparation method and application

Abstract

The present invention discloses a water-soluble mango peel packaging film, its preparation method, and application. Mango peel dry powder is added to a polyethyleneimine solution, along with appropriate amounts of a plasticizer and a solubilizer, to prepare a water-soluble packaging film material. The water-soluble mango peel packaging film obtained in the present invention is made primarily from waste mango peel. It is highly safe and biodegradable, and can address resource waste and environmental pollution issues to a certain extent. The preparation method is simple, meeting the requirements of green and sustainable development. The resulting water-soluble mango peel packaging film is low-cost and exhibits good solubility, making it suitable for use in various fields, including daily chemicals, pharmaceuticals, and food.

Description

Technical Field

[0001] The invention belongs to the technical field of packaging materials, and particularly relates to a water-soluble mango peel packaging film and a preparation method and application thereof. Background Art

[0002] Mango is the world's second-largest tropical fruit, second only to bananas in terms of cultivated area and production. However, during mango processing, a significant amount of peel is discarded, resulting in a low overall utilization rate. Reports indicate that mango peel accounts for approximately 15-20% of the fruit's weight, resulting in tens of thousands of tons of peel being discarded worldwide each year. Currently, there is no effective way to utilize these peels, resulting in a waste of agricultural resources and environmental pollution.

[0003] Currently, the main method for the comprehensive utilization of mango peel processing waste is to process it into animal feed, but this method has very low added value. Furthermore, mango peel, after certain processing methods, can be used as a medicine, offering anti-inflammatory, cough-relieving, expectorant, diuretic, and laxative properties. Studies have shown that mango peel contains significant amounts of mangiferin, flavonoids, xanthones, polysaccharides, and dietary fiber, all of which possess antioxidant and antibacterial properties. The antibacterial components in mango peel can inhibit Pseudomonas aeruginosa, Escherichia coli, and Pseudomonas aeruginosa, and also have inhibitory effects on influenza viruses. Furthermore, the phenolic hydroxyl groups in polyphenolic compounds can donate an electron to free radicals, deactivating them, thereby endowing mango peel with potent antioxidant activity. This finding has been validated in experiments with hyperlipidemic rats. Therefore, mango peel, as a new source of natural antioxidants and antimicrobial agents, has potential for widespread application in the food, pharmaceutical, and cosmetics industries.

[0004] Furthermore, by leveraging mango peel's natural antioxidant and antimicrobial properties, waste mango peel can be used in food packaging and water-soluble films. Patent CN115005265A discloses a fermented mango peel extract that can be sprayed on the surface of meat products to preserve them. The core concept of this patent is to utilize the enzyme-inhibiting and antioxidant properties of plant essential oils, phenolic compounds, and polysaccharides in mango peel to preserve pork. However, this method requires freeze-drying the mango peels, and the production of the mango peel fermentation requires the addition of kefir grains and whole milk, resulting in a complex fermentation process that is not conducive to large-scale production. Furthermore, patent CN108822458B describes a water-soluble mango peel film. Polyvinyl alcohol, cyclodextrin, and starch are sequentially added to a mango peel extract concentrate. The resulting mango peel water-soluble film can be used to package meat products and inhibit microorganisms. This water-soluble film exhibits excellent mechanical strength and gas barrier properties, but the preparation method also requires low-temperature drying and concentration of the mango peels, making it relatively complex. However, the present invention incorporates mango peel into a water-soluble material to create a water-soluble mango peel packaging film. This packaging film not only meets the trend of environmentally friendly and green development, but also solves the problem of mango peel resource waste, and has a wide range of applications. Therefore, simplifying the film-making process while maintaining the film's excellent properties is the key to current research on water-soluble mango peel packaging films. Summary of the Invention

[0005] To address the shortcomings and deficiencies of the prior art, the present invention provides a method for preparing a water-soluble mango peel packaging film. By adding bioactive, biodegradable mango peel to a water-soluble material, a water-soluble composite packaging film is prepared for packaging and storage.

[0006] Another object of the present invention is to provide a fully biodegradable mango peel packaging film prepared by the above method.

[0007] Another object of the present invention is to provide an application of the above-mentioned water-soluble mango peel packaging film.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A method for preparing a water-soluble mango peel packaging film comprises the following steps:

[0010] Mango peel powder is dissolved in an organic solvent, and a plasticizer and a thickener are added to control the solution viscosity to be 600-2500 mPa.s. The solution is mixed to obtain a casting solution. The degassed casting solution is scraped to a film thickness of 50-200 μm, and the film is dried to obtain the water-soluble mango peel packaging film.

[0011] Preferably, the organic solvent is a polyethyleneimine solution with a mass fraction of 2-5%, and the amount of mango peel powder added is 5-20% (w / v%) of the solution.

[0012] Preferably, the plasticizer is at least one of glycerol and sorbitol, and the thickener is at least one of carboxymethyl cellulose, sodium alginate, and soybean oil.

[0013] Preferably, the added amount of the plasticizer is 0.2-0.5% of the mass of the peel slurry; the added amount of the thickener is 0.2-0.5% of the mass of the peel slurry.

[0014] Preferably, the preparation steps of the mango peel powder are: washing the mango peel with water to remove wax on the surface of the peel, drying at 50-60° C. to constant weight, crushing, and passing through a 100-mesh sieve to obtain the mango peel powder.

[0015] Preferably, the drying process is performed at 50-70° C. for 30-60 min.

[0016] Preferably, the film scraping step comprises allowing the casting liquid to stand to remove bubbles, pouring the degassed casting liquid onto a PET base film for film scraping, and peeling off the PET base film after drying to obtain a water-soluble mango peel packaging film.

[0017] The water-soluble mango peel packaging film is prepared according to the above method.

[0018] Preferably, the water-soluble mango peel packaging film has a thickness of 30 to 80 μm.

[0019] Application of a water-soluble mango peel packaging film in the field of storage and packaging.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] (1) The main raw material of the membrane material prepared by the present invention is mango peel, which has biodegradability, low cost, and is conducive to the recycling and reuse of waste resources;

[0022] (2) The film preparation method of the present invention is simple, convenient, non-toxic, and belongs to green processing technology, which is suitable for large-scale production;

[0023] (3) The mango peel packaging film prepared by the present invention can slowly release the mango aroma and increase the fragrance of the packaging film;

[0024] (4) The mango peel packaging film prepared by the present invention has high water solubility, fast dissolution speed and high dissolution rate, and can quickly dissolve and release the substances in the package;

[0025] (5) The water-soluble mango peel packaging film prepared by the present invention can be used for storage and packaging in various industries such as daily chemicals, medicines, and foods, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1This is a photo of the fully biodegradable mango peel packaging film obtained in Example 1.

[0027] Figure 2 These are the water vapor transmission rate test results of the fully biodegradable mango peel packaging films obtained in Examples 1 to 4 and Comparative Examples 1 to 3, and the passion fruit peel packaging films obtained in Comparative Examples 4 to 5. DETAILED DESCRIPTION

[0028] The present invention will be described in further detail below with reference to examples and drawings, but the embodiments of the present invention are not limited thereto.

[0029] In the examples of the present invention, if the specific conditions are not specified, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. All raw materials and reagents used without specifying the manufacturer are conventional products that can be purchased from the market.

[0030] Example 1

[0031] (1) Take fresh mangoes, wash the mango peel with deionized water to remove the wax on the peel surface. Remove the pulp, retain the mango peel, dry it at 60°C for 24 hours, grind it with a universal grinder for 10 minutes, and pass it through a 100-mesh sieve to obtain mango peel powder for later use.

[0032] (2) Add 5% (w / v%) mango peel powder to a 5% polyethyleneimine solution, and add 0.5% glycerol and 0.2% sodium alginate to the solution. Stir in a 60°C water bath for 3 hours to obtain a uniform solution, i.e., the casting solution. The casting solution is allowed to stand for 30 minutes to remove bubbles. The degassed casting solution is poured onto a PET base film and scraped to a film thickness of 100 μm. After drying at 50°C for 1 hour, the casting solution is dried to form a film. The PET base film is peeled off to obtain a water-soluble mango peel packaging film.

[0033] Example 2

[0034] (1) Take fresh mangoes, wash the mango peel with deionized water to remove the wax on the peel surface. Remove the pulp, retain the mango peel, dry it at 60°C for 24 hours, grind it with a universal grinder for 10 minutes, and pass it through a 100-mesh sieve to obtain mango peel powder for later use.

[0035] (2) Add 10% (w / v%) mango peel powder to a 5% polyethyleneimine solution, and add 0.2% glycerol and 0.2% sodium alginate to the solution. Stir in a 60°C water bath for 3 hours to obtain a uniform solution, i.e., the casting solution. The casting solution is allowed to stand for 30 minutes to remove bubbles. The degassed casting solution is poured onto a PET base film and a film is scraped to a thickness of 100 μm. After drying at 50°C for 1 hour, the casting solution is dried to form a film. The PET base film is peeled off to obtain a water-soluble mango peel packaging film.

[0036] Example 3

[0037] (1) Take fresh mangoes, wash the mango peel with deionized water to remove the wax on the peel surface. Remove the pulp, retain the mango peel, dry it at 60°C for 24 hours, grind it with a universal grinder for 10 minutes, and pass it through a 100-mesh sieve to obtain mango peel powder for later use.

[0038] (2) Add 10% (w / v%) mango peel powder to a 3% polyethyleneimine solution, and add 0.2% glycerol and 0.5% sodium alginate to the solution. Stir in a 60°C water bath for 3 hours to obtain a uniform solution, i.e., the casting solution. The casting solution is allowed to stand for 30 minutes to remove bubbles. The degassed casting solution is poured onto a PET base film and a film is scraped to a thickness of 100 μm. After drying at 50°C for 1 hour, the casting solution is dried to form a film. The PET base film is peeled off to obtain a water-soluble mango peel packaging film.

[0039] Example 4

[0040] (1) Take fresh mangoes, wash the mango peel with deionized water to remove the wax on the peel surface. Remove the pulp, retain the mango peel, dry it at 60°C for 24 hours, grind it with a universal grinder for 10 minutes, and pass it through a 100-mesh sieve to obtain mango peel powder for later use.

[0041] (2) Add 15% (w / v%) mango peel powder to a 3% polyethyleneimine solution, and add 0.2% glycerol and 0.5% sodium alginate to the solution. Stir in a 60°C water bath for 3 hours to obtain a uniform solution, i.e., the casting solution. The casting solution is allowed to stand for 30 minutes to remove bubbles. The degassed casting solution is poured onto a PET base film and scraped to a film thickness of 100 μm. After drying at 50°C for 1 hour, the casting solution is dried to form a film. The PET base film is peeled off to obtain a water-soluble mango peel packaging film.

[0042] Comparative Example 1

[0043] (1) Take fresh mangoes, wash the mango peel with deionized water to remove the wax on the peel surface. Remove the pulp, retain the mango peel, freeze-dry for 24 hours, grind it with a universal grinder for 10 minutes, and pass it through a 100-mesh sieve to obtain mango peel powder for later use.

[0044] (2) Add 5% (w / v%) mango peel powder to a 5% polyethyleneimine solution, and add 0.5% glycerol and 0.2% sodium alginate to the solution. Stir in a 60°C water bath for 3 hours to obtain a uniform solution, i.e., the casting solution. The casting solution is allowed to stand for 30 minutes to remove bubbles. The degassed casting solution is poured onto a PET base film and scraped to a film thickness of 100 μm. After drying at 50°C for 1 hour, the casting solution is dried to form a film. The PET base film is peeled off to obtain a water-soluble mango peel packaging film.

[0045] Comparative Example 2

[0046] (1) Take fresh mangoes, wash the mango peel with deionized water to remove the wax on the peel surface. Remove the pulp, retain the mango peel, dry it at 60°C for 24 hours, grind it in a low-temperature grinder for 10-15 minutes, and pass it through a 100-mesh sieve to obtain mango peel powder for later use.

[0047] (2) Add 5% (w / v%) mango peel powder to a 5% polyethyleneimine solution, and add 0.5% glycerol and 0.2% sodium alginate to the solution. Stir in a 60°C water bath for 3 hours to obtain a uniform solution, i.e., the casting solution. The casting solution is allowed to stand for 30 minutes to remove bubbles. The degassed casting solution is poured onto a PET base film and scraped to a film thickness of 100 μm. After drying at 50°C for 1 hour, the casting solution is dried to form a film. The PET base film is peeled off to obtain a water-soluble mango peel packaging film.

[0048] Comparative Example 3

[0049] (3) Take fresh mangoes, wash the mango peel with deionized water to remove the wax on the peel surface. Remove the pulp, retain the mango peel, dry it at 60°C for 24 hours, grind it in a low-temperature grinder for 10-15 minutes, and pass it through a 100-mesh sieve to obtain mango peel powder for later use.

[0050] (4) The mango peel powder is placed in an acetone aqueous solution for ultrasonic extraction. After extraction, the solution is placed in a centrifuge for centrifugation, filtered, and vacuum concentrated until all the acetone is evaporated to obtain a mango peel extract concentrate, which is stored at 0-3°C for later use.

[0051] (5) Add 5% (w / v%) mango peel powder to a 5% polyethyleneimine solution, and add 0.5% glycerol and 0.2% sodium alginate to the solution. Stir in a 60°C water bath for 3 h to obtain a uniform solution, i.e., the casting solution. The casting solution is allowed to stand for 30 min to remove bubbles. The degassed casting solution is poured onto a PET base film and a film is scraped to a thickness of 100 μm. After drying at 50°C for 1 h, the casting solution is dried to form a film. The PET base film is peeled off to obtain a water-soluble mango peel packaging film.

[0052] Comparative Example 4

[0053] (1) Take passion fruit, remove the wax on the pulp and peel surface, retain the peel, dry at 60 ° C for 24 h, use a universal grinder to grind for 10 min, pass through a 100 mesh sieve, and obtain passion fruit peel powder for later use.

[0054] (2) The passion fruit peel powder is placed in an acetone aqueous solution for ultrasonic extraction. After extraction, the solution is placed in a centrifuge for centrifugation, filtered, and vacuum concentrated until all the acetone is evaporated to obtain a passion fruit peel extract concentrate, which is stored at 0-3°C for later use.

[0055] (3) Add 5% (w / v%) passion fruit peel powder to a 5% polyethyleneimine solution, and add 0.5% glycerol and 0.2% sodium alginate to the solution. Stir in a 60°C water bath for 3 h to obtain a uniform solution, i.e., the casting solution. The casting solution is allowed to stand for 30 min to remove bubbles. The degassed casting solution is poured onto a PET base film and scraped to a film thickness of 100 μm. After drying at 50°C for 1 h, the casting solution is dried to form a film. The PET base film is peeled off to obtain a water-soluble mango peel packaging film.

[0056] Comparative Example 5

[0057] (1) Take passion fruit, remove the wax on the pulp and peel surface, retain the peel, dry at 60 ° C for 24 h, use a universal grinder to grind for 10 min, pass through a 100 mesh sieve, and obtain passion fruit peel powder for later use.

[0058] (2) The passion fruit peel powder is placed in an acetone aqueous solution for ultrasonic extraction. After extraction, the solution is placed in a centrifuge for centrifugation, filtered, and vacuum concentrated until all the acetone is evaporated to obtain a passion fruit peel extract concentrate, which is stored at 0-3°C for later use.

[0059] 10% (w / v%) passion fruit peel powder was added to a 5% polyethyleneimine solution. 0.2% glycerol and 0.2% sodium alginate were also added to the solution. The solution was stirred in a 60°C water bath for 3 hours to obtain a homogeneous solution, the casting solution. The casting solution was allowed to stand for 30 minutes to remove air bubbles. The degassed casting solution was then poured onto a PET base film and scraped to a thickness of 100 μm. The casting solution was dried at 50°C for 1 hour to form a film. The PET base film was then peeled off to obtain the water-soluble mango peel packaging film.

[0060] Table 1 Water solubility test results of packaging films obtained in Examples and Comparative Examples

[0061]

[0062] Table 2 Mechanical strength test results of fully biodegradable mango peel packaging film

[0063]

[0064] The results show that the water-soluble mango peel film prepared by this patented method is brown in color and has good transparency. As a biodegradable water-soluble film, it dissolves quickly and at a high rate, while also having a low water vapor transmission rate, which helps maintain a dry and low-humidity environment within the packaging.

[0065] The difference between Example 1 and Comparative Example 1 is the drying method of mango peel. Figure 2As shown in Table 1, the hot air drying and freeze drying treatments have no significant effect on the water vapor permeability and solubility of the mango peel after film formation. At the same time, the difference between Example 1 and Comparative Example 2 lies in the way the dried mango peel is ground into powder. Figure 2 The results in Table 1 show that the two common treatment methods of grinding into powder with a universal grinder and low-temperature pulverization have no significant effect on the water vapor permeability and solubility of mango peel after film formation. In addition, the difference between Comparative Example 1 and Comparative Example 2 is that the film is made directly from mango peel powder and the film is made from mango peel extract concentrate (i.e., mango peel pectin). Figure 2 As shown in Table 1, there is no significant difference in water vapor permeability and solubility between the films prepared from mango peel powder and mango peel pectin.

[0066] Based on the above results, it can be seen that the mango peel is ground into powder after hot air drying, and then a very small amount of plasticizer and thickener are added before flat film formation. The performance of the water-soluble mango peel film obtained is no significantly different from that of the film made from freeze-dried and low-temperature ground pectin. In addition, this method is simpler to operate and more conducive to large-scale production.

[0067] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a water-soluble mango peel packaging film, characterized in that: The following steps are involved: Mango peel powder is dissolved in an organic solvent, a plasticizer and a thickener are added, the solution viscosity is controlled to be 600-2500 mPa.s, and the mixture is mixed to obtain a casting solution; the degassed casting solution is scraped to a film thickness of 50-200 μm, and the film is dried to obtain the water-soluble mango peel packaging film; The organic solvent is a polyethyleneimine solution with a mass fraction of 5%, and the added mass of mango peel powder is 5% of the volume of the polyethyleneimine solution; The added mass of the plasticizer is 0.5% of the mass of the mixed solution of mango peel powder and organic solvent; the added mass of the thickener is 0.2% of the mass of the mixed solution of mango peel powder and organic solvent; The preparation steps of the mango peel powder are: washing the mango peel with water to remove wax on the surface of the peel, drying at 50-60° C. to constant weight, crushing, and passing through a 100-mesh sieve to obtain the mango peel powder.

2. The preparation method according to claim 1, characterized in that The plasticizer is at least one of glycerol and sorbitol, and the thickener is at least one of carboxymethyl cellulose, sodium alginate, and soybean oil.

3. The preparation method according to claim 1, characterized in that The drying process is performed at 50-70° C. for 30-60 min.

4. The preparation method according to claim 1, characterized in that The film scraping step comprises the following steps: allowing the casting liquid to stand to remove bubbles, pouring the degassed casting liquid onto the PET base film for film scraping, and peeling off the PET base film after drying to obtain the water-soluble mango peel packaging film.

5. The water-soluble mango peel packaging film prepared by the method according to any one of claims 1 to 4.

6. The water-soluble mango peel packaging film according to claim 5, characterized in that: The thickness of the water-soluble mango peel packaging film is 30 to 80 μm.

7. Use of the water-soluble mango peel packaging film according to any one of claims 5 to 6 in the field of storage and packaging.

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