Meat product preservative film and preparation method thereof

Abstract

The invention belongs to the technical field of meat product preservation, and discloses a meat product preservative film and a preparation method thereof. The preparation method comprises the following steps: performing electrostatic spinning on a composite material of chitosan and polylactic acid to obtain a base membrane, then coating the upper surface and the lower surface of the base membrane with a sodium alginate solution of a natural antibacterial agent, and then firmly combining an antibacterial layer with the base membrane through crosslinking of calcium chloride. According to the preservative film disclosed by the invention, the base film and the antibacterial layer are compounded, and a compact net-shaped structure is formed on the surface of the base film through crosslinking, so that the oxygen barrier property can be remarkably improved, and the mechanical property of the preservative film can also be improved. The moisture absorbent is added into the base film, water vapor generated during storage of the meat product can be removed, chitosan in the base film and a natural antibacterial agent in the antibacterial layer enable the base film and the antibacterial layer to have good antibacterial property, and the shelf life of the meat product can be remarkably prolonged by combining high oxygen barrier property.

Description

Technical Field

[0001] The invention relates to the technical field of meat product preservation, in particular to a meat product preservation film and a preparation method thereof. Background Art

[0002] Meat is an indispensable ingredient in daily life. From slaughter to secondary processing or sale, fresh meat preservation is an essential step. On the one hand, fresh meat preservation can prevent bacteria growth, ensure food safety, and extend shelf life. On the other hand, it can improve the appearance of meat products. With the improvement of people's quality of life, higher requirements are put forward for meat preservation.

[0003] At present, traditional meat preservation methods include freezing, refrigeration, special preservation materials, etc., among which the preservation method of special preservation materials is widely used for its convenience, practicality and low cost. Existing special preservation materials include preservatives, cling films, etc. For example, Patent 202010460122.4 discloses a meat antibacterial and antiseptic cling film with a five-layer structure: a first polyethylene layer, a first vinyl acetate copolymer layer, a polyvinylidene chloride layer, a second vinyl acetate copolymer layer, and a second polyethylene layer. The first polyethylene layer includes nano-silver polyethylene antibacterial masterbatch, which can effectively improve the antibacterial and antiseptic properties. This kind of cling film is polymerized with ethylene as the masterbatch. Polyethylene cling film is a common type in the market. However, polyethylene has poor degradability and is prone to white pollution. The functional additives such as plasticizers added therein are less safe. At the same time, the use of nano-silver antibacterial agents in this technology is costly and easy to fall off in the film and become ineffective. Regarding the issue of cling film materials and antimicrobial agents, patent 201611105239.0 also discloses that chitosan solution and starch solution are mixed in a certain proportion, a certain volume of glycerol is added, dried to form a film, and then the carboxyl groups of the antimicrobial peptide molecules are covalently cross-linked with the amino groups of the chitosan molecules on the film by a cross-linking agent to obtain a degradable antimicrobial cling film. This cling film combines the excellent antimicrobial properties of antimicrobial peptides and chitosan, but its mechanical properties are poor, its flexibility is low, and its oxygen barrier properties are poor, which cannot meet the needs of multiple scenarios of fresh-keeping applications.

[0004] Therefore, how to provide a degradable and low-cost meat product cling film that has both antibacterial and mechanical properties is an urgent problem that needs to be solved. Summary of the invention

[0005] The object of the present invention is to provide a meat product cling film and a preparation method thereof, so as to solve the problems of poor mechanical properties, low flexibility, poor oxygen barrier properties and the like of the existing cling film.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a meat product cling film, comprising the following steps:

[0008] Mixing chitosan, polylactic acid, a moisture absorbent, acetic acid and water to obtain a spinning solution;

[0009] Electrospinning the spinning solution to obtain a base film;

[0010] The antibacterial agent solution is coated on the upper and lower surfaces of the base film, and then cross-linked in a calcium chloride solution to form an antibacterial layer on the upper and lower surfaces of the base film, thereby obtaining the meat product fresh-keeping film;

[0011] The antibacterial agent solution comprises an antibacterial agent and sodium alginate.

[0012] Preferably, in the above method for preparing a meat product cling film, the mass ratio of the chitosan, polylactic acid and hygroscopic agent is 10-20:15-30:1-6.

[0013] Preferably, in the above-mentioned method for preparing a cling film for meat products, the conditions for electrospinning include: a voltage of 10 to 20 kV; a receiving distance of 15 to 20 cm; and an injection speed of 0.3 to 1 mL / h.

[0014] Preferably, in the above method for preparing a cling film for meat products, the thickness of the base film is 20 to 60 μm.

[0015] Preferably, in the above method for preparing a cling film for meat products, in the antibacterial agent solution, the mass concentration of the antibacterial agent is 5-10%; the mass concentration of sodium alginate is 3-10%.

[0016] Preferably, in the above-mentioned method for preparing a meat product cling film, the coating amount of the upper and lower surfaces is independently 1 to 5 mL / cm 2 .

[0017] Preferably, in the above-mentioned method for preparing a meat product cling film, the antibacterial agent is one or more of tea polyphenols, cinnamaldehyde, and orange peel extract.

[0018] Preferably, in the above-mentioned method for preparing a cling film for meat products, the cross-linking time is 30 to 120 minutes; the cross-linking temperature is 25 to 50° C.; and the mass concentration of the calcium chloride solution is 1 to 10%.

[0019] Preferably, in the above method for preparing a cling film for meat products, the thickness of the antibacterial layers on the upper and lower surfaces is independently 5 to 30 μm.

[0020] The invention also provides a meat product fresh-keeping film prepared by the method for preparing the meat product fresh-keeping film.

[0021] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention uses a composite material of chitosan and polylactic acid to obtain a base film through electrostatic spinning, and then coats a sodium alginate solution of a natural antibacterial agent on the upper and lower surfaces of the base film, and then cross-links the antibacterial layer with calcium chloride to firmly combine the antibacterial layer with the base film. The preservative film of the present invention forms a dense mesh structure on the surface of the base film by composite base film and antibacterial layer, and cross-links, which can significantly improve the oxygen barrier property, and the mechanical properties of the preservative film can also be improved. The present invention also adds a hygroscopic agent to the base film, which can remove the water vapor generated during the storage of meat products, and the chitosan in the base film and the natural antibacterial agent in the antibacterial layer make the base film and the antibacterial layer have good antibacterial properties, combined with high oxygen barrier properties, can significantly extend the shelf life of meat products. In addition, the raw materials used in the present invention are all natural material extracts or degradable materials, which are green and environmentally friendly, can be degraded after a period of use, and will not cause white pollution. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing a meat product cling film, comprising the following steps:

[0024] Mixing chitosan, polylactic acid, a moisture absorbent, acetic acid and water to obtain a spinning solution;

[0025] Electrospinning the spinning solution to obtain a base film;

[0026] The antibacterial agent solution is coated on the upper and lower surfaces of the base film, and then cross-linked in a calcium chloride solution to form antibacterial layers on the upper and lower surfaces of the base film, thereby obtaining the meat product fresh-keeping film.

[0027] In the present invention, the mass ratio of chitosan, polylactic acid and hygroscopic agent is preferably 10-20:15-30:1-6, more preferably 12-18:20-27:3-5, and more preferably 14:25:5.

[0028] In the present invention, the usage ratio of chitosan, acetic acid and water is preferably 10-20 g: 10-50 mL: 100-200 mL, more preferably 12-18 g: 20-40 mL: 120-160 mL, and more preferably 14 g: 30 mL: 150 mL.

[0029] In the present invention, the molecular weight of the polylactic acid is preferably 10,000 to 100,000, more preferably 40,000 to 80,000, and even more preferably 60,000.

[0030] In the present invention, the moisture absorbent is preferably calcium carbonate or montmorillonite, and more preferably calcium carbonate.

[0031] In the present invention, the conditions for electrospinning include: the voltage is preferably 10-20 kV, more preferably 15-18 kV, and more preferably 16 kV; the receiving distance is preferably 15-20 cm, more preferably 15-17 cm, and more preferably 16 cm; the injection speed is preferably 0.3-1 mL / h, more preferably 0.5-1 mL / h, and more preferably 1 mL / h.

[0032] In the present invention, the thickness of the base film is preferably 20 to 60 μm, more preferably 30 to 50 μm, and even more preferably 48 μm.

[0033] In the present invention, the antibacterial agent solution comprises an antibacterial agent and sodium alginate.

[0034] In the present invention, the antibacterial agent solution further comprises water.

[0035] In the present invention, in the antibacterial agent solution, the mass concentration of the antibacterial agent is preferably 5-10%, more preferably 7-10%, more preferably 9%; the mass concentration of sodium alginate is preferably 3-10%, more preferably 4-6%, more preferably 5%.

[0036] In the present invention, the coating amount of the upper and lower surfaces is preferably 1 to 5 mL / cm 2 , more preferably 2 to 4 mL / cm 2 , more preferably 3 mL / cm 2 .

[0037] In the present invention, the antibacterial agent is preferably one or more of tea polyphenols, cinnamaldehyde, and orange peel extract, more preferably one or two of tea polyphenols and orange peel extract, and more preferably tea polyphenols and orange peel extract.

[0038] In the present invention, the preparation method of the tangerine peel extract is: extracting the dried tangerine peel with ethanol at a ratio of 1 g:10 mL at 40° C. for 24 h, and then distilling off the ethanol to obtain the tangerine peel extract. The tangerine peel extracts used in the embodiments of the present invention are all prepared by this method.

[0039] In the present invention, the cross-linking time is preferably 30 to 120 min, more preferably 50 to 90 min, more preferably 60 min; the cross-linking temperature is preferably 25 to 50°C, more preferably 27 to 40°C, more preferably 30°C.

[0040] In the present invention, the mass concentration of the calcium chloride solution is preferably 1 to 10%, more preferably 5 to 8%, and more preferably 7%.

[0041] In the present invention, the thickness of the antibacterial layer on the upper and lower surfaces is preferably 5 to 30 μm, more preferably 15 to 28 μm, and even more preferably 25 μm.

[0042] The invention also provides a meat product fresh-keeping film prepared by the method for preparing the meat product fresh-keeping film.

[0043] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Example 1

[0045] This embodiment provides a meat product cling film, and the preparation method thereof comprises the following steps:

[0046] (1) chitosan, polylactic acid (molecular weight 60,000), calcium carbonate, acetic acid, and water were stirred and mixed in a ratio of 14 g: 25 g: 5 g: 30 mL: 150 mL to obtain a spinning solution;

[0047] (2) electrospinning the spinning solution under the following conditions: voltage of 16 kV, receiving distance of 16 cm, injection speed of 1 mL / h, and obtaining a base film with a thickness of 48 μm;

[0048] (3) An antimicrobial solution containing 5% tea polyphenols, 4% orange peel extract, and 5% sodium alginate was applied to the upper and lower surfaces of the base film, with the coating amount being 3 mL / cm 2 Then, the film was cross-linked in a 7% calcium chloride solution at 30°C for 60 minutes, washed with water, and dried to form an antibacterial layer of 25 μm thick on the upper and lower surfaces of the base film to obtain a meat product cling film.

[0049] Example 2

[0050] This embodiment provides a meat product cling film, and the preparation method thereof comprises the following steps:

[0051] (1) chitosan, polylactic acid (molecular weight 60,000), montmorillonite, acetic acid, and water are stirred and mixed in a ratio of 10 g: 20 g: 2 g: 10 mL: 100 mL to obtain a spinning solution;

[0052] (2) electrospinning the spinning solution under the following conditions: voltage of 12 kV, receiving distance of 15 cm, injection speed of 0.5 mL / h, to obtain a base film with a thickness of 32 μm;

[0053] (3) An aqueous solution of cinnamaldehyde with a mass concentration of 5% and sodium alginate with a mass concentration of 3% was used as an antimicrobial solution, and the antimicrobial solution was applied to the upper and lower surfaces of the base film, with a coating amount of 1 mL / cm 2 Then, the film was cross-linked in a 3% calcium chloride solution at 25°C for 40 minutes, washed with water, and dried to form an antibacterial layer with a thickness of 17 μm on the upper and lower surfaces of the base film to obtain a meat product cling film.

[0054] Example 3

[0055] This embodiment provides a meat product cling film, and the preparation method thereof comprises the following steps:

[0056] (1) chitosan, polylactic acid (molecular weight 60,000), calcium carbonate, acetic acid, and water were stirred and mixed in a ratio of 17 g: 27 g: 3 g: 20 mL: 180 mL to obtain a spinning solution;

[0057] (2) electrospinning the spinning solution under the following conditions: voltage of 18 kV, receiving distance of 16 cm, injection speed of 0.8 mL / h, to obtain a base film with a thickness of 38 μm;

[0058] (3) An aqueous solution of 8% tangerine peel extract and 7% sodium alginate was used as an antimicrobial solution, and the antimicrobial solution was applied to the upper and lower surfaces of the base film at a coating amount of 2 mL / cm 2 Then, the film was cross-linked in a 3% calcium chloride solution at 40°C for 80 minutes, washed with water, and dried to form an antibacterial layer with a thickness of 21 μm on the upper and lower surfaces of the base film to obtain a meat product cling film.

[0059] Example 4

[0060] This embodiment provides a meat product cling film, and the preparation method thereof comprises the following steps:

[0061] (1) chitosan, polylactic acid (molecular weight 60,000), calcium carbonate, acetic acid, and water are stirred and mixed in a ratio of 10 g: 30 g: 6 g: 50 mL: 200 mL to obtain a spinning solution;

[0062] (2) electrospinning the spinning solution under the following conditions: voltage of 20 kV, receiving distance of 15 cm, injection speed of 1 mL / h, to obtain a base film with a thickness of 54 μm;

[0063] (3) An aqueous solution of 8% tea polyphenols and 8% sodium alginate was used as an antimicrobial solution, and the antimicrobial solution was applied to the upper and lower surfaces of the base film at a coating amount of 4 mL / cm 2Then, the film was cross-linked in a 5% calcium chloride solution at 25°C for 90 minutes, washed with water, and dried to form an antibacterial layer with a thickness of 27 μm on the upper and lower surfaces of the base film to obtain a meat product cling film.

[0064] Comparative Example 1

[0065] This comparative example provides a meat product cling film, which is specifically referred to in Example 1, except that there is no antibacterial layer on the upper and lower surfaces of the base film, that is, step (3) is not performed in the preparation method.

[0066] Comparative Example 2

[0067] This comparative example provides a meat product cling film, which is specifically referred to in Example 1, except that in the preparation method, in step (3), the antibacterial agent solution is coated and then dried to obtain the meat product cling film, and no cross-linking with the calcium chloride solution is performed.

[0068] Comparative Example 3

[0069] This comparative example provides a meat product cling film, which is specifically referred to in Example 1, except that the antibacterial agent solution in step (3) of the preparation method does not contain sodium alginate, and the calcium chloride solution is not cross-linked.

[0070] Comparative Example 4

[0071] This comparative example provides a meat product cling film, which is specifically referred to in Example 1, except that the antibacterial agent solution in step (3) of the preparation method does not contain natural antibacterial agents such as tea polyphenols and orange peel extract.

[0072] The meat product cling films prepared in the above Examples 1 to 4 and Comparative Examples 1 to 4 were tested for mechanical properties, antibacterial properties, and oxygen permeability. The results are shown in Table 1.

[0073] Table 1 Performance test results of meat product cling film

[0074]

[0075]

[0076] As shown in Table 1, the cling film of the present invention has a tensile strength of up to 10 MPa, an elongation at break of more than 100%, an antibacterial property of more than 99%, and an oxygen permeability as low as 17.7 mL / cm 2 · days, having good oxygen barrier properties, antibacterial properties and mechanical properties, can meet the requirements of meat product preservation, and can extend the shelf life. According to Comparative Examples 1 to 3, it can be seen that the antibacterial layer on the surface of the base film has an impact on the mechanical properties, antibacterial properties and oxygen permeability, and from Comparative Example 4, it can be seen that the natural antibacterial agent used in the present invention also further improves the antibacterial properties.

[0077] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a meat product cling film, characterized in that: The following steps are involved: Mixing chitosan, polylactic acid, a moisture absorbent, acetic acid and water to obtain a spinning solution; Electrospinning the spinning solution to obtain a base film; The antibacterial agent solution is coated on the upper and lower surfaces of the base film, and then cross-linked in a calcium chloride solution to form an antibacterial layer on the upper and lower surfaces of the base film, thereby obtaining the meat product fresh-keeping film; The antibacterial agent solution comprises an antibacterial agent and sodium alginate.

2. The method for preparing a meat product cling film according to claim 1, characterized in that: The mass ratio of the chitosan, polylactic acid and moisture absorbent is 10-20:15-30:1-6.

3. The method for preparing a meat product cling film according to claim 2, characterized in that: The conditions for the electrostatic spinning include: a voltage of 10 to 20 kV; a receiving distance of 15 to 20 cm; and an injection speed of 0.3 to 1 mL / h.

4. The method for preparing a meat product cling film according to claim 1 or 2, characterized in that: The base film has a thickness of 20 to 60 μm.

5. The method for preparing a meat product cling film according to claim 4, characterized in that: In the antibacterial agent solution, the mass concentration of the antibacterial agent is 5-10%; the mass concentration of the sodium alginate is 3-10%.

6. The method for preparing a meat product cling film according to claim 5, characterized in that: The coating amount of the upper and lower surfaces is independently 1 to 5 mL / cm 2 .

7. The method for preparing a meat product cling film according to claim 1 or 6, characterized in that: The antibacterial agent is one or more of tea polyphenols, cinnamaldehyde and orange peel extract.

8. The method for preparing a meat product cling film according to claim 7, characterized in that: The cross-linking time is 30 to 120 minutes; the cross-linking temperature is 25 to 50° C.; and the mass concentration of the calcium chloride solution is 1 to 10%.

9. The method for preparing a meat product cling film according to claim 4, characterized in that: The thickness of the antibacterial layers on the upper and lower surfaces is independently 5 to 30 μm.

10. A meat product fresh-keeping film prepared by the method for preparing a meat product fresh-keeping film according to any one of claims 1 to 9.

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