Edible coating film for meat products and preparation method of edible coating film

Abstract

The invention discloses an edible coating film for meat products and a preparation method thereof, and belongs to the technical field of edible coating films, the edible coating film for meat products comprises an inner layer and an outer layer, one side in contact with the meat products is the inner layer, one side in contact with the environment is the outer layer, and the inner layer comprises edible water-holding food materials and nano cellulose; the outer layer comprises an edible hydrophobic food material. The fresh-keeping agent can be used for keeping the meat product fresh in a high-humidity environment and inhibiting the expansion effect of nanocellulose, and the strength of an edible coating film is not influenced.

Description

Technical Field

[0001] The present invention relates to the technical field of meat product preservation, and specifically relates to an edible coating for meat products and a preparation method thereof. A nano-cellulose reinforced edible coating for meat products and a preparation method thereof Background Art

[0002] Traditional edible coatings have certain limitations in terms of preservation effect. The barrier properties of traditional edible coatings are often poor and cannot effectively prevent the permeation of gases such as oxygen, water vapor, and carbon dioxide, resulting in food being easily affected by the external environment and deteriorating. The mechanical strength of traditional edible coatings is relatively low, and they are prone to cracking or deformation, unable to provide sufficient physical protection and difficult to resist external mechanical damage. Traditional edible coatings mainly delay the water loss and oxidation process of food by forming a physical barrier, and their preservation function is relatively single, unable to meet the diverse requirements of different food preservation needs. The addition of nano-cellulose endows the coating with new functional characteristics. Nano-cellulose has a high degree of crystallinity, its molecular arrangement is tight, forming a dense network structure. This structure can effectively fill the pores in the edible coating, reduce the diffusion channels of gas molecules, and thus significantly improve the gas barrier properties of the coating. Nano-cellulose has extremely high strength, and its tensile strength can be comparable to that of steel. Adding nano-cellulose to the edible coating can significantly improve the mechanical strength of the coating, making it more tough and not easy to break. However, nano-cellulose is hydrophilic and will absorb moisture in the air in a high-humidity environment, resulting in the coating absorbing water and swelling, reducing the strength and barrier properties of the coating. Structural change: The entry of water into the coating will cause changes in its internal structure, resulting in a decrease in the mechanical properties of the coating and affecting the protection effect on meat products.

[0003] The influence of the hydrophilicity of nano-cellulose on the coating properties is environmentally dependent. In a low-humidity environment, its hydrophilicity helps to enhance the water retention and flexibility of the coating; while in a high-humidity environment, it may cause the coating to absorb water and swell, weakening its strength and barrier properties.

[0004] The surface layer uses hydrophobic food materials to block the entry of external moisture, and the inner layer uses water-holding food materials to retain moisture.

[0005] In food packaging, maintaining a low gas permeability of the packaged food materials is crucial for extending the food shelf life. The water absorption of edible water-holding food materials helps to maintain this low permeability.

[0006] If the barrier properties of the packaged food materials decline, the food is easily affected by gases such as oxygen and carbon dioxide, resulting in accelerated deterioration. Therefore, maintaining the barrier properties is crucial for the effectiveness of food packaging. Summary of the Invention

[0007] As described in the above prior art, one of the objectives of the present invention is to provide an edible coating for meat products, which can preserve the freshness of meat products in a high-humidity environment, inhibit the swelling effect of nanocellulose, and does not affect the strength of the edible coating.

[0008] Another objective of the present invention is to provide a method for preparing an edible coating for meat products, which has simple steps and can be industrialized.

[0009] One of the objectives of the present invention is achieved by the following technical solutions:

[0010] The edible coating for meat products includes an inner layer and an outer layer. The side in contact with the meat product is the inner layer, and the side in contact with the environment is the outer layer. The inner layer includes an edible water-holding ingredient and nanocellulose; the outer layer includes an edible hydrophobic ingredient.

[0011] Further, the edible hydrophobic ingredient is one of palm wax, beeswax, and chitosan - zein.

[0012] Further, the edible water-holding ingredient is one of gelatin and arabic gum.

[0013] Further, the source of the nanocellulose is as follows: The soybean hull is sieved and crushed, then soaked in low-temperature water, subjected to high-temperature acid hydrolysis treatment and the reaction is terminated, followed by low-temperature ultrasonic treatment. The obtained solution is dialyzed and then alcohol-precipitated, centrifuged at low temperature and vacuum freeze-dried to obtain soybean hull nanocellulose.

[0014] Further, after the high-temperature acid hydrolysis treatment and the termination of the reaction, followed by low-temperature ultrasonic treatment, it means adding 1:1 - 5 v / v, 0.1 - 12 mol / L hydrochloric acid to the soybean hull solution and stirring at 50 - 90 °C for 1 - 5 h, then adding 1 - 5 times deionized water to terminate the reaction and cooling to room temperature; then the solution is placed in an ultrasonic instrument at 0 - 4 °C and ultrasonicated at 50

[0015] - 400 W for 1 - 10 min, then the solution is centrifuged at 1000 - 4000 rpm for 1 - 15 min, the supernatant is taken, and NaOH is added to adjust the pH of the solution to 5 - 8;

[0016] Dialyzing the obtained solution and then alcohol-precipitating, centrifuging at low temperature and vacuum freeze-drying means dialyzing the solution with adjusted pH for 3 - 7 days, changing deionized water every 6 - 18 h; slowly adding 75% - 95% v / v ethanol solution, diluting the concentrated solution at a ratio of 1:2 - 4 v / v, stirring evenly, placing at 2 - 4 °C for 12 - 48 h, centrifuging at 1000 - 4000 rpm for 5 - 10 min, and vacuum freeze-drying for 24 - 48 h to obtain soybean hull nanocellulose with a particle size < 500 nm.

[0017] The second object of the present invention is achieved by the following technical solutions:

[0018] A method for preparing an edible coating for meat products, comprising the following steps:

[0019] S1. Preparation of the inner layer coating solution: Dissolve the edible water-holding ingredients in water, and fully dissolve them by heating and stirring to form a uniform solution; then add the nano-cellulose, continue heating and stirring to uniformly disperse the nano-cellulose in the solution to form a stable inner layer coating solution;

[0020] S2. Preparation of the outer layer coating solution: Dissolve the edible hydrophobic ingredients in a solvent to form a uniform outer layer coating solution;

[0021] S3. Dip coating method: Immerse the meat product in the inner layer coating solution, then take it out and drain it to form an inner layer coating, and then immerse the meat product in the outer layer coating solution, take it out and drain it to form an outer layer coating, and form an edible coating on the meat product.

[0022] Further, in step S2, if the edible hydrophobic ingredients are the palm wax and the beeswax, heat the palm wax and the beeswax to melt them into a liquid state to form a uniform outer layer coating solution.

[0023] Further, in step S2, if the edible hydrophobic ingredient is chitosan-zein, the preparation of the outer layer coating solution includes the following steps:

[0024] Chitosan solution: Dissolve chitosan powder in an acetic acid solution with a mass percentage of 1%-2%, stir until completely dissolved to form a uniform chitosan solution;

[0025] Zein solution: Dissolve zein powder in ethanol with a volume percentage of 70%-80%, stir to fully dissolve it to form a uniform zein solution;

[0026] In step S3, first immerse the meat product in the chitosan solution, then take it out and dry it; form a chitosan coating, and then immerse the dried chitosan coating in the zein solution to form a zein coating, and dry and cure it. Repeat the coating process multiple times in this way to form a multi-layer coating structure.

[0027] Further, in step S1, in the preparation of the inner layer coating solution, calculated by weight, the amount added to water is: 30-50 parts of edible water-holding ingredients, 5-15 parts of nano-cellulose; in step S2, in the preparation of the outer layer coating solution, calculated by weight, the amount added to the solvent is: 20-30 parts of edible hydrophobic ingredients.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] The edible coating for meat products provided by the present invention uses nanocellulose as the reinforcing phase, which can improve the strength, flexibility and barrier properties of the edible coating, thereby enhancing the protection effect of the coating on meat products, extending their shelf life, and enabling the traditional edible coating to play a better role in meat product preservation and other aspects. The outer layer includes an edible hydrophobic food material, which prevents moisture in a high-humidity environment from entering the gaps between nanocelluloses, reduces the hygroscopicity of nanocelluloses, and inhibits the influence of the swelling of nanocelluloses on the performance of the edible coating; the inner layer includes an edible water-holding food material and nanocellulose. The edible water-holding food material first absorbs the moisture lost from the surface of the meat product, making it difficult for nanocellulose to come into contact with a large amount of moisture and swell, thereby maintaining the overall denseness of the edible coating, maintaining the performance of nanocellulose, and extending the shelf life of the food. Detailed implementation manners

[0030] Next, with reference to specific embodiments, the present invention will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0031] Different meanings

[0032] Water absorption: Refers to the ability of a food material to absorb moisture from the surrounding environment. A food material with strong water absorption can quickly absorb moisture from the air or a contacting water medium.

[0033] Water holding capacity: Refers to the ability of a food material to retain the absorbed moisture after absorbing moisture. A food material with strong water holding capacity can effectively lock in moisture and reduce moisture loss.

[0034] Different action mechanisms

[0035] Water absorption: Mainly depends on the hydrophilic groups and porous structure of the food material. Hydrophilic groups (such as hydroxyl groups, carboxyl groups, etc.) can form hydrogen bonds with water molecules to promote water absorption; the porous structure provides a surface area for water adsorption.

[0036] Water holding capacity: Mainly relies on the internal network structure and intermolecular forces of the food material. A tight network structure can physically encapsulate moisture and prevent it from escaping; intermolecular forces (such as hydrogen bonds, van der Waals forces, etc.) can further bind water molecules.

[0037] Example 1

[0038] This example provides an edible coating for meat products, which includes an inner layer and an outer layer. The side in contact with the meat product is the inner layer, and the side in contact with the environment is the outer layer. The inner layer includes an edible water-holding food material, gelatin, and nanocellulose; the outer layer includes an edible hydrophobic food material, palm wax.

[0039] In this embodiment, the source of nanocellulose is as follows: The soybean hulls are sieved and crushed, then soaked in low-temperature water, the reaction is terminated after high-temperature acidolysis treatment, followed by low-temperature ultrasonic treatment. The obtained solution is dialyzed and then precipitated with alcohol, centrifuged at low temperature and freeze-dried under vacuum to obtain soybean hull nanocellulose.

[0040] In this embodiment, after the high-temperature acidolysis treatment, the reaction is terminated, and then the low-temperature ultrasonic treatment means adding 1:1 - 5 v / v, 0.1 - 12 mol / L hydrochloric acid to the soybean hull solution, stirring at 50 - 90 °C for 1 - 5 h, then adding 1 - 5 times deionized water to terminate the reaction, and cooling to room temperature; then the solution is placed in an ultrasonic instrument and ultrasonicated at 0 - 4 °C and 50 - 400 W for 1 - 10 min, and then the solution is centrifuged at 1000 - 4000 rpm for 1 - 15 min, the supernatant is taken, and NaOH is added to adjust the pH of the solution to 5 - 8;

[0041] Dialyzing the obtained solution and then precipitating with alcohol, centrifuging at low temperature and freeze-drying under vacuum means dialyzing the solution with adjusted pH for 3 - 7 days, changing deionized water every 6 - 18 h; slowly adding 75% - 95% v / v ethanol solution, diluting the concentrated solution at a ratio of 1:2 - 4 v / v, stirring evenly, placing at 2 - 4 °C for 12 - 48 h, centrifuging at 1000 - 4000 rpm for 5 - 10 min, and freeze-drying under vacuum for 24 - 48 h to obtain soybean hull nanocellulose with a particle size < 500 nm.

[0042] This embodiment also provides a method for preparing an edible coating for meat products, including the following steps:

[0043] S1. Preparation of the inner-layer coating solution: Dissolve the edible water-holding ingredient gelatin in water, and make it fully dissolve by heating and stirring to form a uniform solution; then add nanocellulose, continue heating and stirring to make the nanocellulose evenly dispersed in the solution to form a stable inner-layer coating solution;

[0044] S2. Preparation of the outer-layer coating solution: If the edible hydrophobic ingredient is palm wax, heat the palm wax to melt it into a liquid state to form a uniform outer-layer coating solution;

[0045] S3. Dip coating method: Immerse the meat product in the inner-layer coating solution, then take it out and drain to form an inner-layer coating, and then immerse the meat product in the outer-layer coating solution, take it out and drain to form an outer-layer coating, and form an edible coating on the meat product.

[0046] In this embodiment, in step S1, in the preparation of the inner-layer coating solution, by weight, the amounts added to water are: 50 parts of the edible water-holding ingredient and 5 parts of nanocellulose; in step S2, in the preparation of the outer-layer coating solution, by weight, the amount added to the solvent is: 25 parts of the edible hydrophobic ingredient.

[0047] In this embodiment, edible hydrophobic food materials

[0048] Palm tree wax: It has suitable surface chemical properties and can be used to prepare edible superhydrophobic coatings. By prefabricating a certain concentration of wax acetone emulsion and then spraying it onto the surface of packaged food materials, a superhydrophobic coating can be formed on the food material surface after the acetone volatilizes. This coating can effectively reduce the residual waste of liquid foods in containers. Palm tree wax, beeswax, chitosan - zein multilayer film, polylactic acid

[0049] Beeswax: A natural hydrophobic food material, edible, non - toxic and harmless, can be used to prepare edible superhydrophobic coatings. Similar to palm tree wax, through specific processing, a superhydrophobic layer can be formed on the surface of packaged food materials to reduce the residue of liquid on the food surface.

[0050] Chitosan - zein multilayer film: Utilize the amphoteric property of zein and the self - assembly to form hydrophobic surface particles to establish an edible hydrophobic film food material. This multilayer film has high hydrophobicity and can be used for food packaging to reduce the problem of rapid microbial growth caused by increased moisture during food transportation.

[0051] Edible water - holding food materials

[0052] Gelatin: A common food additive, having good film - forming property and water - holding property, can be used to prepare edible coatings. Adding gelatin to the coating can enhance the water - holding property of the coating, enabling it to effectively lock in moisture and reduce moisture loss.

[0053] Arabic gum: A natural polysaccharide substance, having good water - holding property and film - forming property, can be used to prepare edible coatings. Arabic gum can form a coating with a three - dimensional network structure, effectively locking in moisture and improving the water - holding property of the coating.

[0054] Water absorption and swelling mechanism of nanocellulose

[0055] Water penetration: Water molecules will penetrate into the gaps between nanocelluloses in a high - humidity environment, causing the coating to swell.

[0056] Hydrogen bond effect: Hydrophilic groups (such as hydroxyl groups) on the surface of nanocellulose form hydrogen bonds with water molecules. The entry of water molecules will disrupt the hydrogen - bond network between nanocelluloses, resulting in the loosening of the coating structure and further exacerbating the swelling.

[0057] Interface water molecule effect: Excessive interface water molecules weaken the interface strength between nanocelluloses, hinder the load - transfer ability, and lead to a decrease in the strength and barrier properties of the coating.

[0058] When the edible water-holding food material absorbs water, it can prevent the excessive water absorption and swelling of nanocellulose, thereby maintaining the structural integrity of nanocellulose and maintaining its strength. If nanocellulose absorbs water and swells excessively, the internal interactions such as hydrogen bonds will be weakened, resulting in a decrease in strength. However, the water absorption of the edible water-holding food material avoids this situation.

[0059] Fruit preservation: Coating the surface of fruits with an edible coating containing nanocellulose can effectively reduce the water loss of fruits, inhibit the invasion of microorganisms, and at the same time delay the respiration and ripening processes of fruits, thereby extending the shelf life of fruits.

[0060] Meat preservation: For meat products, an edible coating containing nanocellulose can prevent the evaporation of water on the surface of meat, maintain the tenderness and juiciness of meat, and at the same time inhibit the growth and reproduction of bacteria and reduce the spoilage and deterioration of meat.

[0061] Baked food preservation: Coating the surface of baked foods such as bread and cakes with an edible coating enhanced with nanocellulose can prevent the drying and hardening of foods, maintain the softness and taste of foods, and at the same time extend their shelf life.

[0062] Dipping method: Immerse the meat product in the inner coating solution to ensure that a layer of coating solution is evenly attached to the surface of the meat product, and then take it out and drain it to form a uniform film layer of the inner coating on the surface of the meat product. After the inner coating is dried and formed, immerse it in the outer coating solution again, take it out and drain it to make the outer coating evenly cover the surface of the inner coating.

[0063] Select food materials with strong water-holding ability but weak hygroscopicity, such as gelatin, gum arabic, etc. If the product to be packaged itself contains water, the inner edible water-holding food material can prevent the loss of this water and maintain the stability of the water content of the product; the outer layer uses an edible hydrophobic food material to block external water. Even if the external environmental humidity is high, the hydrophobic food material on the outer layer can effectively block the entry of water, while the inner water-holding food material is responsible for maintaining the water inside the coating. The two work together to achieve the effect of "only holding water without absorbing water". Even if a small amount of water is absorbed by the edible water-holding food material, it will not form a continuous channel for gas diffusion, so it will not significantly increase the gas permeability.

[0064] Example 2

[0065] This example provides an edible coating for meat products, including an inner layer and an outer layer. The side in contact with the meat product is the inner layer, and the side in contact with the environment is the outer layer. The inner layer includes the edible water-holding food materials gum arabic and nanocellulose; the outer layer includes the edible hydrophobic food material beeswax.

[0066] In this embodiment, the source of nanocellulose is as follows: The soybean hull is sieved and crushed, then soaked in low-temperature water, the reaction is terminated after high-temperature acid hydrolysis treatment, followed by low-temperature ultrasonic treatment. The obtained solution is dialyzed and then alcohol-precipitated, centrifuged at low temperature and freeze-dried under vacuum to obtain soybean hull nanocellulose.

[0067] In this embodiment, after the high-temperature acid hydrolysis treatment, the reaction is terminated, and then the low-temperature ultrasonic treatment means adding 1:1 - 5 v / v, 0.1 - 12 mol / L hydrochloric acid to the soybean hull solution, stirring at 50 - 90 °C for 1 - 5 h, then adding 1 - 5 times deionized water to terminate the reaction, and cooling to room temperature; then the solution is placed in an ultrasonic instrument and ultrasonicated at 0 - 4 °C, 50 - 400 W for 1 - 10 min, then the solution is centrifuged at 1000 - 4000 rpm for 1 - 15 min, the supernatant is taken, and NaOH is added to adjust the pH of the solution to 5 - 8;

[0068] Dialyzing the obtained solution and then alcohol-precipitating, centrifuging at low temperature and freeze-drying under vacuum means dialyzing the solution with adjusted pH for 3 - 7 days, changing deionized water every 6 - 18 h; slowly adding 75% - 95% v / v ethanol solution, diluting the concentrate at a ratio of 1:2 - 4 v / v, stirring evenly, placing at 2 - 4 °C for 12 - 48 h, centrifuging at 1000 - 4000 rpm for 5 - 10 min, and freeze-drying under vacuum for 24 - 48 h to obtain soybean hull nanocellulose with a particle size < 500 nm.

[0069] This embodiment also provides a method for preparing an edible coating for meat products, including the following steps:

[0070] S1. Preparation of the inner coating solution: Dissolve the edible water-holding ingredient gum arabic in water, and make it fully dissolve by heating and stirring to form a uniform solution; then add nanocellulose, continue heating and stirring to make the nanocellulose uniformly disperse in the solution to form a stable inner coating solution;

[0071] S2. Preparation of the outer coating solution: If the edible hydrophobic ingredient is beeswax, heat the beeswax to melt it into a liquid state to form a uniform outer coating solution;

[0072] S3. Dip coating method: Immerse the meat product in the inner coating solution, then take it out and drain to form an inner coating, and then immerse the meat product in the outer coating solution, take it out and drain to form an outer coating, so as to form an edible coating on the meat product.

[0073] In this embodiment, in step S1, in the preparation of the inner coating solution, calculated by weight, the amounts added to water are: 30 parts of the edible water-holding ingredient and 15 parts of nanocellulose; in step S2, in the preparation of the outer coating solution, calculated by weight, the amounts added to the solvent are: 30 parts of the edible hydrophobic ingredient.

[0074] Example 3

[0075] This embodiment provides an edible coating for meat products, which includes an inner layer and an outer layer. The side in contact with the meat product is the inner layer, and the side in contact with the environment is the outer layer. The inner layer includes the edible water-holding ingredients gelatin and nanocellulose; the outer layer includes the edible hydrophobic ingredient chitosan-zein.

[0076] In this embodiment, the source of nanocellulose is as follows: The soybean hulls are sieved and pulverized, then soaked in low-temperature water, the reaction is terminated after high-temperature acidolysis treatment, followed by low-temperature ultrasonic treatment. The obtained solution is dialyzed and then alcohol-precipitated, centrifuged at low temperature and vacuum freeze-dried to obtain soybean hull nanocellulose.

[0077] In this embodiment, after the high-temperature acidolysis treatment, the reaction is terminated and then low-temperature ultrasonic treatment is carried out, which means adding 1:1 - 5 v / v, 0.1 - 12 mol / L hydrochloric acid to the soybean hull solution and stirring at 50 - 90 °C for 1 - 5 h, then adding 1 - 5 times deionized water to terminate the reaction and cooling to room temperature; then the solution is placed in an ultrasonic instrument and ultrasonicated at 0 - 4 °C, 50 - 400 W for 1 - 10 min, and then the solution is centrifuged at 1000 - 4000 rpm for 1 - 15 min, the supernatant is taken, and NaOH is added to adjust the pH of the solution to 5 - 8;

[0078] Dialyzing the obtained solution and then alcohol-precipitating, centrifuging at low temperature and vacuum freeze-drying means dialyzing the solution with adjusted pH for 3 - 7 days, changing deionized water every 6 - 18 h; slowly adding 75% - 95% v / v ethanol solution, diluting the concentrated solution at a ratio of 1:2 - 4 v / v, stirring evenly, placing at 2 - 4 °C for 12 - 48 h, centrifuging at 1000 - 4000 rpm for 5 - 10 min, and vacuum freeze-drying for 24 - 48 h to obtain soybean hull nanocellulose with a particle size < 500 nm.

[0079] This embodiment also provides a method for preparing an edible coating for meat products, including the following steps:

[0080] S1. Preparation of the inner layer coating solution: Dissolve the edible water-holding ingredient gelatin in water, and make it fully dissolve by heating and stirring to form a uniform solution; then add nanocellulose, continue heating and stirring to make the nanocellulose evenly dispersed in the solution to form a stable inner layer coating solution;

[0081] S2. Preparation of the outer layer coating solution: If the edible hydrophobic ingredient is chitosan-zein, the preparation of the outer layer coating solution includes the following steps:

[0082] Chitosan solution: Dissolve chitosan powder in an acetic acid solution with a mass percentage of 1% - 2%, stir until completely dissolved to form a uniform chitosan solution;

[0083] Zein solution: Dissolve zein powder in ethanol with a volume percentage of 70%-80%, stir to fully dissolve it, and form a uniform zein solution;

[0084] In step S3, first immerse the meat product in the chitosan solution, then take it out and dry it to form a chitosan coating film. Then immerse the dried chitosan coating film in the zein solution to form a zein coating film, and dry and cure it. Repeat the coating process multiple times in this way to form a multi-layer coating film structure;

[0085] S3. Dipping method: Immerse the meat product in the inner layer coating solution, then take it out and drain it to form an inner layer coating film. Then immerse the meat product in the outer layer coating solution, take it out and drain it to form an outer layer coating film, and form an edible coating film on the meat product.

[0086] In this embodiment, in step S1, in the preparation of the inner layer coating solution, calculated by weight, the amount of water added is: 40 parts of edible water-holding ingredients and 10 parts of nanocellulose; in step S2, in the preparation of the outer layer coating solution, calculated by weight, the amount of solvent added is: 20 parts of edible hydrophobic ingredients.

[0087] The above embodiments are only the preferred embodiments of the present invention, and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art on the basis of the present invention belong to the scope of protection required by the present invention.

Claims

1. An edible coating for meat products, characterized in that, It includes an inner layer and an outer layer. The side in contact with meat products is the inner layer, and the side in contact with the environment is the outer layer. The inner layer includes an edible water-holding ingredient and nanocellulose; the outer layer includes an edible hydrophobic ingredient.

2. The edible coating for meat products according to claim 1, wherein The edible hydrophobic ingredient is one of palm wax, beeswax, and chitosan-zein.

3. The edible coating for meat products according to claim 1, wherein The edible water-holding ingredient is one of gelatin and gum arabic.

4. The edible coating for meat products according to claim 1, wherein The source of the nanocellulose is as follows: The soybean hull is sieved and pulverized, then soaked in low-temperature water, the reaction is terminated after high-temperature acidolysis treatment, followed by low-temperature ultrasonic treatment. The obtained solution is dialyzed and then alcohol-precipitated, centrifuged at low temperature, and vacuum freeze-dried to obtain soybean hull nanocellulose.

5. The edible coating for meat products according to claim 4, wherein After the high-temperature acidolysis treatment, the reaction is terminated, and then low-temperature ultrasonic treatment means adding 1:1 - 5 v / v, 0.1 - 12 mol / L hydrochloric acid to the soybean hull solution, stirring at 50 - 90 °C for 1 - 5 h, then adding 1 - 5 times deionized water to terminate the reaction, and cooling to room temperature; then the solution is placed in an ultrasonic instrument and ultrasonically treated at 0 - 4 °C, 50 - 400 W for 1 - 10 min, then the solution is centrifuged at 1000 - 4000 rpm for 1 - 15 min, and the supernatant is taken, and NaOH is added to adjust the pH of the solution to 5 - 8; Dialyzing the adjusted pH solution for 3 - 7 days, changing deionized water every 6 - 18 h; Slowly adding 75% - 95% v / v ethanol solution, diluting the concentrated solution at a ratio of 1:2 - 4 v / v, stirring evenly, placing at 2 - 4 °C for 12 - 48 h, centrifuging at 1000 - 4000 rpm for 5 - 10 min, and vacuum freeze-drying for 24 - 48 h to obtain soybean hull nanocellulose with a particle size <500 nm.

6. The preparation method of the edible coating for meat products according to any one of claims 1 to 5, characterized in that, It includes the following steps: S1. Preparation of the inner layer coating solution: Dissolve the edible water-holding ingredient in water, and make it fully dissolve by heating and stirring to form a uniform solution; then add the nanocellulose, continue heating and stirring to make the nanocellulose uniformly disperse in the solution to form a stable inner layer coating solution; S2. Preparation of the outer layer coating solution: Dissolve the edible hydrophobic ingredient in a solvent to form a uniform outer layer coating solution; S3. Dip coating method: Immerse the meat product in the inner layer coating solution, then take it out and drain to form an inner layer coating, and then immerse the meat product in the outer layer coating solution, take it out and drain to form an outer layer coating, and form an edible coating on the meat product.

7. The edible coating for meat products according to claim 6, wherein, In step S2, if the edible hydrophobic ingredient is the palm wax or the beeswax, heat the palm wax and the beeswax to melt into a liquid state to form a uniform outer layer coating solution.

8. The edible coating for meat products according to claim 6, wherein In step S2, if the edible hydrophobic ingredient is chitosan-zein, the preparation of the outer layer coating solution includes the following steps: Chitosan solution: Dissolve chitosan powder in an acetic acid solution with a mass percentage of 1% - 2%, stir until completely dissolved to form a uniform chitosan solution; Zein solution: Dissolve zein powder in ethanol with a volume percentage of 70%-80% ethanol, stir to fully dissolve it to form the uniform zein solution; In step S3, first immerse the meat product in the chitosan solution, then take it out and dry it to form a chitosan coating film. Then immerse the dried chitosan coating film in the zein solution to form a zein coating film, and dry and cure it. Repeat the multiple coatings alternately to form a multi-layer coating film structure.

9. The edible coating for meat products according to claim 6, wherein In step S1, in the preparation of the inner layer coating solution, by weight, the amount of water added is: 30-50 parts of edible water-holding ingredients and 5-15 parts of nanocellulose; in step S2, in the preparation of the outer layer coating solution, by weight, the amount of the solvent added is: 20-30 parts of edible hydrophobic ingredients.

10. The edible coating for meat products according to claim 6, wherein, The meat product is fresh meat or cooked meat product.