Salmon skin gelatin composite film with high mechanical property and preparation method thereof

Abstract

The invention belongs to the technical field of composite membrane preparation, and particularly relates to a salmon skin gelatin composite membrane with high mechanical performance and a preparation method thereof. Salmon skin gelatin, a chitosan solution, absolute ethyl alcohol, glycerin, sorbitol, montmorillonite, silicon dioxide, anhydrous sodium sulfite and a genipin acetic acid aqueous solution are used as raw materials, salmon skin gelatin protein and chitosan have good compatibility, protein molecules are fully stretched in the heat treatment denaturation process, the water absorption hydraulic radius of the protein molecules is increased, and the water absorption rate of the protein molecules is increased. The molecules interact with each other to form a compact space gel net structure; glycerol and sorbitol enhance the strength and toughness of the composite film; montmorillonite and silicon dioxide are beneficial to improving the mechanical strength of the composite film; in addition, the genipin acetic acid aqueous solution is added to modify free amino groups on salmon skin gelatin protein molecules, so that the interaction force among molecules is improved. Therefore, after the raw materials are specifically combined, synergistic interaction is achieved, and the mechanical performance of the salmon skin gelatin composite film is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of composite film preparation, and particularly relates to a salmon skin gelatin composite film with high mechanical properties and a preparation method thereof. Background Art

[0002] Food packaging composite film is a high-performance packaging material made from a variety of raw materials. It can effectively extend the shelf life of food, improve food safety and market competitiveness, and at the same time meet the requirements of environmental protection and sustainable development. It has been widely used in the field of food packaging.

[0003] Numerous reports exist on research related to food packaging composite films. For example, Chinese Patent CN 103740117B describes a food packaging composite film prepared using soy protein isolate, gelatin, and K-carrageenan as raw materials; Chinese Patent CN 101199314 A describes a food packaging composite film prepared using soy protein and wheat gluten as raw materials; and Chinese Patent CN 114539635 B describes a food packaging composite film prepared using pitaya peel crude polysaccharide, punicalagin, a plasticizer, and a solvent as raw materials. However, these food packaging composite films suffer from poor mechanical strength, poor thermal stability, poor appearance quality, or limited functionality, limiting their practical applications. Therefore, how to obtain a food packaging composite film with improved overall performance by modifying the raw materials is an urgent issue in this field. Summary of the Invention

[0004] The present invention aims to provide a salmon skin gelatin composite film with high mechanical properties and a preparation method thereof, which has good comprehensive performance, high mechanical properties and excellent appearance quality.

[0005] The invention provides a salmon skin gelatin composite film with high mechanical properties. The salmon skin gelatin composite film comprises the following raw materials, measured by weight: 3-6 parts of salmon skin gelatin, 2-3 parts of chitosan solution, 4.5-5.5 parts of anhydrous ethanol, 3-4 parts of a plasticizer, 3-5 parts of a reinforcing agent, 0.05-0.15 parts of anhydrous sodium sulfite, 1-1.5 parts of a genipin acetic acid aqueous solution, and 100 parts of water.

[0006] The plasticizers include: glycerol and sorbitol;

[0007] The reinforcing agent includes montmorillonite and silicon dioxide.

[0008] Preferably, the mass ratio of glycerol to sorbitol is 1:1.5-2.0;

[0009] The mass concentration of the genipin acetic acid aqueous solution is 1%-1.5%;

[0010] The mass ratio of the montmorillonite to silicon dioxide is 3-4:1.

[0011] Preferably, the preparation method of the salmon skin gelatin comprises:

[0012] Soaking the cleaned salmon skin in a citric acid solution and a compound bacterial solution in sequence to obtain the soaked salmon skin;

[0013] Performing pre-freezing treatment, freezing treatment and standing on the soaked salmon skin in sequence to obtain the salmon skin after standing;

[0014] Mixing the salmon skin after standing with water, and then performing gelatin extraction, filtration and drying in sequence to obtain salmon skin gelatin;

[0015] The compound bacterial solution comprises a Bacillus amyloliquefaciens bacterial solution and a yeast bacterial solution.

[0016] Preferably, the mass concentration of the citric acid solution is 0.75%-1.0%;

[0017] In the compound bacterial solution, the effective viable bacteria numbers of the Bacillus amyloliquefaciens bacterial solution and the yeast bacterial solution are respectively 1×10 6 -2×10 6 cfu / mL;

[0018] The soaking time of the salmon skin with the citric acid solution is 10-15 min;

[0019] The soaking time of the salmon skin with the compound bacterial solution is 25-30 min.

[0020] Preferably, the parameters of the pre-freezing treatment include: the temperature is -4°C to -1°C, and the time is 5-10 min;

[0021] The parameters of the freezing treatment include: the temperature is -30°C to -20°C, and the time is 3-4 min;

[0022] The parameters of the standing include: the temperature is 18°C to 20°C, and the time is 1-2 min.

[0023] Preferably, the mass-to-volume ratio of the salmon skin after standing to water is 1 g:7-8 mL;

[0024] The parameters of the gelatin extraction include: the temperature is 45-50°C, and the time is 5-6 h.

[0025] The present invention provides a preparation method of the salmon skin gelatin composite film according to the above technical solution, comprising the following steps:

[0026] At 40-60°C, adding salmon skin gelatin into distilled water in sequence and mixing evenly to obtain a salmon skin gelatin solution;

[0027] Mix the salmon skin gelatin solution with a chitosan solution having a mass concentration of 2%-2.5% to obtain a mixture;

[0028] Add absolute ethanol, a plasticizer, a reinforcing agent, and anhydrous sodium sulfite to the mixture in sequence and mix evenly to obtain a mixed solution;

[0029] Adjust the pH of the mixed solution to 8.0, and perform stirring, water bath heating, and ultrasonic treatment in sequence to obtain a degassed solution;

[0030] Use genipin acetic acid aqueous solution to perform biological crosslinking and drying on the degassed solution to obtain a salmon skin gelatin composite film.

[0031] Preferably, the stirring is magnetic stirring;

[0032] The parameters of the water bath heating include: the time is 1.5-2 h, and the temperature is 60-65 °C;

[0033] The parameters of the ultrasonic treatment include: the frequency is 120-150 HZ, and the time is 15-20 min.

[0034] Preferably, the parameters of the biological crosslinking include: the temperature is 25-30 °C, and the time is 20-25 h.

[0035] The present invention provides the application of the salmon skin gelatin composite film described in the above technical solution in the preparation of products for improving the mechanical properties of food packaging films.

[0036] Beneficial effects:

[0037] The present invention provides a salmon skin gelatin composite film with high mechanical properties. Calculated by mass parts, the salmon skin gelatin composite film comprises the following raw materials: 3 - 6 parts of salmon skin gelatin, 2 - 3 parts of chitosan solution, 4.5 - 5.5 parts of absolute ethanol, 3 - 4 parts of plasticizer, 3 - 5 parts of reinforcing agent, 0.05 - 0.15 parts of anhydrous sodium sulfite, 1 - 1.5 parts of genipin acetic acid aqueous solution, and 100 parts of water; the plasticizer includes glycerol and sorbitol; the reinforcing agent includes montmorillonite and silica. The present invention uses salmon skin gelatin, chitosan solution, absolute ethanol, glycerol, sorbitol, montmorillonite, anhydrous sodium sulfite, and genipin acetic acid aqueous solution as raw materials. Among them, salmon skin gelatin protein and chitosan solution have good compatibility. During the heat treatment denaturation process, protein molecules fully unfold, and their own water absorption hydrodynamic radius increases, and then interact with each other to form a tight spatial gel network structure; glycerol and sorbitol are polyols, and after mixing, they can form a more stable hydrogen bond network with other materials, thereby enhancing the toughness and flexibility of the composite film; after mixing silica with montmorillonite, silica can cover the surface of montmorillonite to form a silica layer containing a large number of silanol groups, thereby improving the hydrophobicity and dispersibility of montmorillonite and enhancing its mechanical properties; in addition, adding genipin acetic acid aqueous solution modifies the free amino groups on the salmon skin gelatin protein molecules, enhancing the intermolecular interaction force. Therefore, after the above raw materials are specifically combined, they work synergistically to improve the mechanical properties of the salmon skin gelatin composite film. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0039] Figure 1 The experimental sample provided by the present invention;

[0040] Figure 2 The experimental flow chart provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] In the present invention, unless otherwise specified, the raw materials, equipment, and methods used are all conventional selections.

[0042] The water used in the present invention is preferably distilled water.

[0043] In order to further illustrate the present invention, the following will describe in detail the solutions provided by the present invention in combination with the embodiments, but they cannot be understood as limiting the protection scope of the present invention.

[0044] Chitosan solution: 2 g of chitosan (the deacetylation degree of chitosan ≥ 85%) was dissolved in 100 mL of acetic acid solution (the volume concentration of acetic acid solution was 2%) to obtain a chitosan solution with a mass concentration of 2% for standby.

[0045] Example 1

[0046] A preparation method of a salmon skin gelatin composite film with high mechanical properties (for the specific flow chart, see Figure 2 ), and the steps are as follows:

[0047] (1) Preparation of salmon skin gelatin

[0048] The salmon skin was cleaned and the scales and epidermal fat were removed, and then cut into small fish skin pieces with a length and width of about 5 mm for standby;

[0049] The small fish skin pieces were completely immersed in a citric acid solution with a mass concentration of 0.75% for 10 min, and then fished out; then the small fish skin pieces were completely immersed in the compound bacterial solution for 30 min (the compound bacterial solution included a Bacillus amyloliquefaciens bacterial solution and a yeast bacterial solution with an effective viable count of 1×10 6 cfu / mL), fished out and air-dried to obtain the soaked fish skin;

[0050] At -4°C, the soaked fish skin was pretreated for 8 min, then at -20°C, the fish skin was frozen for 4 min, and then at 18°C, it was left standing for 2 min to obtain the standing fish skin;

[0051] The standing fish skin was mixed with water at a mass-to-volume ratio of 1 g:8 mL, and then gelatinized at 50°C for 6 h to obtain a gelatin solution; the gelatin solution was filtered to remove impurities and undissolved fish skin, etc., and then dried at 45°C for 22 h to obtain salmon skin gelatin;

[0052] (2) Preparation of salmon skin gelatin composite film

[0053] 100 g of distilled water at a temperature of 50°C was added to a beaker, and then 6 g of the salmon skin gelatin in step (1) was added to the beaker and completely dissolved, and then 2 g of chitosan solution, 5 g of absolute ethanol, 3 g of plasticizer (the plasticizer was composed of glycerol and sorbitol mixed in a mass ratio of 1:1.5), 5 g of reinforcing agent (the reinforcing agent was composed of montmorillonite and silicon dioxide mixed in a mass ratio of 3:1), and 0.1 g of anhydrous sodium sulfite were successively added to the beaker, and mixed evenly under magnetic stirring to obtain a mixed solution;

[0054] The pH value of the mixed solution was adjusted to 8.0, and magnetic stirring was carried out, and it was heated in a water bath at 60°C for 2 h; then it was subjected to ultrasonic defoaming and degassing treatment at 120 HZ for 18 min to obtain a degassed solution;

[0055] 15 mL of the degassed solution was coated on a glass culture dish with a diameter of 10 cm, and 1 g of genipin acetic acid aqueous solution (the mass concentration of genipin acetic acid aqueous solution was 1%) was sprayed, and then reacted at 30°C for 24 hours; the culture dish containing the film-forming solution was then dried at 50°C under a blast for 15 hours, and then allowed to stand at 25-28°C for 7 hours, and then softened in a 90°C water bath for 45 seconds before peeling off the film to obtain a salmon skin gelatin composite film.

[0056] Example 2

[0057] A method for preparing a salmon skin gelatin composite film with high mechanical properties, comprising the following steps:

[0058] (1) Preparation of salmon skin gelatin

[0059] Clean the salmon skin and remove the scales and skin fat, then cut into small pieces about 5mm long and wide for later use;

[0060] The fish skin pieces were completely immersed in a citric acid solution with a mass concentration of 1.0% for 10 min and then taken out; the fish skin pieces were completely immersed in a composite bacterial solution for 30 min (the effective viable bacteria count in the composite bacterial solution was 2 × 10 6 cfu / mL of Bacillus amyloliquefaciens liquid and yeast liquid), fish out and dry to obtain the soaked fish skin;

[0061] The soaked fish skin was pretreated at -1°C for 8 minutes, then frozen at -25°C for 4 minutes, and then allowed to stand at 20°C for 2 minutes to obtain a fish skin after standing;

[0062] The fish skin after standing was mixed with water in a mass volume ratio of 1 g:8 mL, and the mixture was extracted at 50°C for 6 hours to obtain a gelatin solution; the gelatin solution was filtered to remove impurities and undissolved fish skin, and then dried at 45°C for 22 hours to obtain salmon skin gelatin;

[0063] (2) Preparation of salmon skin gelatin composite film

[0064] 100 g of distilled water at 50° C. was added to a beaker, and then 6 g of the salmon skin gelatin in step (1) was added to the beaker in sequence and mixed evenly. Then, 2 g of chitosan solution, 5 g of anhydrous ethanol, 3 g of plasticizer (the plasticizer was prepared by mixing glycerol and sorbitol in a mass ratio of 1:1.5), 5 g of reinforcing agent (the reinforcing agent was prepared by mixing montmorillonite and silicon dioxide in a mass ratio of 3:1), and 0.1 g of anhydrous sodium sulfite were added to the beaker in sequence, and mixed evenly under magnetic stirring to obtain a mixed solution.

[0065] The pH value of the mixed solution was adjusted to 8.0, and the mixture was subjected to magnetic stirring and heated in a water bath at 60° C. for 2 h. The mixture was then subjected to ultrasonic defoaming and degassing treatment at 120 Hz for 18 min to obtain a degassed solution.

[0066] 15 mL of the degassed solution was coated on a glass culture dish with a diameter of 10 cm, and 1 g of genipin acetic acid aqueous solution (the mass concentration of genipin acetic acid aqueous solution was 1%) was sprayed, and then reacted at 30°C for 24 hours; the culture dish containing the film-forming solution was then dried at 50°C under a blast for 15 hours, and then allowed to stand at 25-28°C for 7 hours, and then softened in a 90°C water bath for 45 seconds before peeling off the film to obtain a salmon skin gelatin composite film.

[0067] Comparative Example 1

[0068] The only difference from Example 1 is that the salmon skin gelatin in Example 1 is replaced by conventionally purchased salmon skin gelatin.

[0069] Comparative Example 2

[0070] The only difference from Example 1 is that the process of step (1) is as follows:

[0071] (1) Preparation of salmon skin gelatin

[0072] Clean the salmon skin and remove the scales and skin fat, then cut into small pieces about 5mm long and wide for later use;

[0073] The fish skin pieces were completely immersed in a 0.75% sodium dodecylbenzenesulfonate aqueous solution for 1 hour, removed and dried to obtain the soaked fish skin;

[0074] The soaked fish skin was pretreated at -4°C for 8 minutes, then frozen at -20°C for 4 minutes, and then allowed to stand at 18°C for 2 minutes to obtain a fish skin after standing;

[0075] The fish skin after standing was mixed with water in a mass-to-volume ratio of 1g:8mL, and then extracted at 50°C for 6 hours to obtain a gelatin solution; the gelatin solution was filtered to remove impurities and undissolved fish skin, and then dried at 45°C for 22 hours to obtain salmon skin gelatin.

[0076] Comparative Example 3

[0077] The only difference from Example 1 is that the process of step (2) is as follows:

[0078] (2) Preparation of salmon skin gelatin composite film

[0079] Add 100 g of distilled water at 50 °C to a beaker, and then sequentially add 6 g of the salmon skin gelatin from step (1) to the beaker and mix evenly. Then, sequentially add 2 g of chitosan solution, 5 g of absolute ethanol, 3 g of a plasticizer (the plasticizer is composed of glycerol and sorbitol mixed in a mass ratio of 1:2.5), 5 g of a reinforcing agent (the reinforcing agent is composed of montmorillonite and silica mixed in a mass ratio of 1:3), and 0.1 g of anhydrous sodium sulfite to the beaker, and mix evenly under magnetic stirring to obtain a mixed solution;

[0080] Adjust the pH value of the mixed solution to 8.0, and perform magnetic stirring. Heat it in a water bath at 60 °C for 1.5 h; then, perform ultrasonic defoaming and degassing treatment at 120 HZ for 18 min to obtain a degassed solution;

[0081] Take 15 mL of the degassed solution and coat it on a glass petri dish with a diameter of 10 cm, and spray 1 g of genipin acetic acid aqueous solution (the mass concentration of the genipin acetic acid aqueous solution is 1%), and then react at 30 °C for 24 h; then, dry the petri dish containing the film-forming solution in a blast at 50 °C for 15 h, then let it stand at 25 - 28 °C for 7 h, and then soften it in a 90 °C water bath for 45 s and then peel off the film to obtain a salmon skin gelatin composite film.

[0082] Comparative Example 4

[0083] The difference from Example 1 is only that the process of step (2) is as follows:

[0084] (2) Prepare a salmon skin gelatin composite film

[0085] Add 100 g of distilled water at 50 °C to a beaker, and then sequentially add 6 g of the salmon skin gelatin from step (1) to the beaker and mix evenly; then, sequentially add 2 g of chitosan solution, 5 g of absolute ethanol, 3 g of a plasticizer (the plasticizer is composed of glycerol and sorbitol mixed in a mass ratio of 1:1.5), 5 g of a reinforcing agent (the reinforcing agent is montmorillonite), and 0.1 g of anhydrous sodium sulfite to the beaker, and mix evenly under magnetic stirring to obtain a mixed solution;

[0086] Adjust the pH value of the mixed solution to 8.0, and perform magnetic stirring. Heat it in a water bath at 60 °C for 1.5 h; then, perform ultrasonic defoaming and degassing treatment at 120 HZ for 18 min to obtain a degassed solution;

[0087] Take 15 mL of the degassed solution and coat it on a glass petri dish with a diameter of 10 cm, and then react at 30 °C for 24 h; then, dry the petri dish containing the film-forming solution in a blast at 50 °C for 15 h, then let it stand at 25 - 28 °C for 7 h, and then soften it in a 90 °C water bath for 45 s and then peel off the film to obtain a salmon skin gelatin composite film.

[0088] Application Example 1

[0089] The salmon skin gelatin composite films prepared in Examples 1-2 and Comparative Examples 1-4 were stored in an environment at 25 °C and a humidity of 50%. Each treatment was repeated three times in parallel. The average mechanical properties of the salmon skin gelatin composite films were statistically analyzed on the 2nd and 7th days of storage. The results are shown in Table 1.

[0090] Among them, the salmon skin gelatin composite films prepared in Examples 1-2 and Comparative Examples 1-4 are as Figure 1 shown (in Figure 1 , A represents the salmon skin gelatin composite film prepared in Example 1, B represents the salmon skin gelatin composite film prepared in Example 2, C represents the salmon skin gelatin composite film prepared in Comparative Example 1, D represents the salmon skin gelatin composite film prepared in Comparative Example 2, E represents the salmon skin gelatin composite film prepared in Comparative Example 3, and F represents the salmon skin gelatin composite film prepared in Comparative Example 4).

[0091] Table 1 Average mechanical properties of salmon skin gelatin composite films in different treatments

[0092]

[0093] Combined with the data in Table 1, it can be known that after preparing the salmon skin gelatin composite film by the technical solutions in Examples 1-2, its mechanical properties are good, and the tensile strength still remains at 3984.058 g after 7 days of storage; at the same time, the H2O permeability, O2 permeability, and CO2 permeability are also relatively stable; comparing the composite film (Example 1) subjected to genipin biological cross-linking modification treatment with the composite film (Comparative Example 4) not subjected to genipin biological cross-linking modification treatment, the composite film treated with genipin biological modification has better mechanical properties. During the storage period of 2-7 days, its tensile strength decreases by 8.65%, the water permeability increases by 5.40%, the oxygen permeability increases by 6.42%, and the carbon dioxide permeability increases by 6.79%. In addition, the surface morphology of the salmon skin gelatin polymer prepared in Examples 1-2 is smoother, denser, and flatter; the mechanical properties are higher, greatly improving the product quality. Combined Figure 1 It can be seen that the product prepared by the present invention presents a light yellow color, has no peculiar smell and no impurities; the appearance quality is better.

[0094] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, not all embodiments. People can also obtain other embodiments according to this embodiment without creative work, and these embodiments all belong to the protection scope of the present invention.

Claims

1. A salmon skin gelatin composite film with high mechanical properties, characterized in that, The salmon skin gelatin composite film, in parts by mass, comprises the following raw materials: 3 - 6 parts of salmon skin gelatin, 2 - 3 parts of chitosan solution, 4.5 - 5.5 parts of absolute ethanol, 3 - 4 parts of plasticizer, 3 - 5 parts of reinforcing agent, 0.05 - 0.15 part of anhydrous sodium sulfite, 1 - 1.5 parts of genipin acetic acid aqueous solution, and 100 parts of water; The plasticizer includes glycerol and sorbitol; The reinforcing agent includes montmorillonite and silica; 2. The salmon skin gelatin composite film according to claim 1, wherein The mass ratio of the glycerol to the sorbitol is 1:1.5 - 2.0; The mass concentration of the genipin acetic acid aqueous solution is 1% - 1.5%; The mass ratio of the montmorillonite to the silica is 3 - 4:1; 3. The salmon skin gelatin composite film according to claim 1, characterized in that The preparation method of the salmon skin gelatin includes: Sequentially soaking the cleaned salmon skin in a citric acid solution and a complex bacterial solution to obtain the soaked salmon skin; Subjecting the soaked salmon skin to pre-freezing treatment, freezing treatment, and standing to obtain the salmon skin after standing; Mixing the salmon skin after standing with water, and then sequentially performing gelatin extraction, filtration, and drying to obtain salmon skin gelatin; The complex bacterial solution includes Bacillus amyloliquefaciens bacterial solution and yeast bacterial solution; 4. The salmon skin gelatin composite film according to claim 3, wherein The mass concentration of the citric acid solution is 0.75% - 1.0%; In the said compound bacterial liquid, the effective viable bacteria counts of Bacillus amyloliquefaciens bacterial liquid and yeast bacterial liquid are respectively 1×10 6 -2×10 6 cfu / mL; The soaking time of the salmon skin in the citric acid solution is 10 - 15 min; The soaking time of the salmon skin in the complex bacterial solution is 25 - 30 min; 5. The salmon skin gelatin composite film according to claim 3, wherein The parameters of the pre-freezing treatment include: temperature of -4°C to -1°C and time of 5 - 10 min; The parameters of the freezing treatment include: temperature of -30°C to -20°C and time of 3 - 4 min; The parameters of the standing include: temperature of 18°C to 20°C and time of 1 - 2 min; 6. The salmon skin gelatin composite film according to claim 3, wherein The mass-to-volume ratio of the salmon skin after standing to water is 1 g:7 - 8 mL; The parameters of the gelatin extraction include: temperature of 45 - 50°C and time of 5 - 6 h; 7. The preparation method of the salmon skin gelatin composite film according to any one of claims 1-6, characterized in that, It includes the following steps: At 40 - 60°C, adding salmon skin gelatin to distilled water and mixing evenly to obtain a salmon skin gelatin solution; Mixing the salmon skin gelatin solution with a chitosan solution having a mass concentration of 2% - 2.5% to obtain a mixture; Sequentially adding absolute ethanol, plasticizer, reinforcing agent, and anhydrous sodium sulfite to the mixture and mixing evenly to obtain a mixed solution; Adjusting the pH of the mixed solution to 8.0, and then sequentially performing stirring, water bath heating, and ultrasonic treatment to obtain a degassed solution; Performing biological crosslinking and drying on the degassed solution with a genipin acetic acid aqueous solution to obtain a salmon skin gelatin composite film; 8. The preparation method according to claim 7, characterized in that, The stirring is magnetic stirring; The parameters of the water bath heating include: time of 1.5 - 2 h and temperature of 60 - 65°C; The parameters of the ultrasonic treatment include: frequency of 120 - 150 HZ and time of 15 - 20 min; 9. The preparation method according to claim 7, characterized in that, The parameters of the biological crosslinking include: temperature of 25 - 30°C and time of 20 - 25 h; 10. Use of the salmon skin gelatin composite film according to any one of claims 1 - 6 in the preparation of a product for improving the mechanical properties of food packaging films.

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