Method for preserving meat product based on self-assembly multifunctional double-layer coating

Abstract

The invention discloses a method for preserving a meat product based on a self-assembled multifunctional double-layer coating film, and belongs to the technical field of preservation of fresh agricultural products. The method for preserving the meat product based on the self-assembled multifunctional double-layer coating comprises the following steps: dissolving chitosan and glycerol in an acetic acid solution to obtain a chitosan solution; the preparation method comprises the following steps: dispersing citral and Tween 80 in water, and carrying out homogenization and ultrasonic treatment to obtain a citral nano-emulsion; uniformly mixing the chitosan solution and the citral nano-emulsion to obtain a citral nano-emulsion-chitosan solution; the preparation method comprises the following steps: dissolving vital gluten in an ethanol solution, extracting and centrifuging to obtain supernate, and adding glycerol to obtain an extract solution; according to the method, fresh meat products are soaked in a citral nanoemulsion-chitosan solution and drained, then soaked in an extract solution and drained, and placed in a self-sealing bag to be stored, and the shelf life of the meat products can be effectively prolonged through the method.

Description

Technical Field

[0001] The invention belongs to the technical field of fresh agricultural product preservation, and in particular relates to a method for preserving meat products based on a self-assembled multifunctional double-layer coating. Background Art

[0002] The logistics loss rate of fresh agricultural products is relatively high, namely 8% for meat, 11% for aquatic products, and 20% for fruits and vegetables, with storage and transportation losses reaching 100 billion yuan. Therefore, how to ensure the safety of fresh agricultural products, maintain their quality and extend their shelf life through effective preservation methods is of great significance to the sustainable development of the fresh food industry.

[0003] As a green and environmentally friendly preservation technology, biological coatings meet consumers' requirements for food safety and health. Chitosan has become a widely studied and applied coating preservation material due to its abundant sources, excellent antibacterial properties and good film-forming properties. In order to further enhance the preservation effect of the coating, current research mainly focuses on the compound use with exogenous preservatives, such as plant extracts, Nisin and lysozyme. Among them, citral is widely used in the preservation of fresh agricultural products such as livestock and poultry meat, aquatic products, fruits and vegetables due to its excellent antibacterial and antioxidant abilities. However, the application of citral is subject to certain limitations, mainly due to its poor water solubility, high volatility, strong aroma, and sensitivity to environmental factors such as light, heat and oxygen. Summary of the invention

[0004] In view of the defects and shortcomings of the prior art, the present invention provides a method for preserving meat products based on a self-assembled multifunctional double-layer coating. The method firstly performs an immersion treatment with a citral nanoemulsion-chitosan solution and then performs an immersion treatment with a gluten extract. The electrostatic interaction between chitosan and gliadin in the gluten extract and the hydrogen bond-driven layer-by-layer self-assembly technology achieves a meat product preservation effect with good barrier, antibacterial and antioxidant properties, thereby avoiding microbial contamination and oxidative damage during transportation, storage and processing, so as to extend the shelf life of livestock and poultry meat and agricultural products and promote the development of the fresh food industry.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for preserving meat products based on a self-assembled multifunctional double-layer coating, the method comprising the following steps:

[0007] (1) dissolving chitosan and glycerol in an acetic acid solution to obtain a chitosan solution; dispersing citral and Tween 80 in water, homogenizing and ultrasonicating to obtain a citral nanoemulsion; and uniformly mixing the chitosan solution and the citral nanoemulsion to obtain a citral nanoemulsion-chitosan solution;

[0008] (2) dissolving gluten in an ethanol solution, extracting and centrifuging, obtaining a supernatant and adding glycerol to obtain an extract solution;

[0009] (3) The fresh meat product is first soaked in the citral nanoemulsion-chitosan solution obtained in step (1), drained, and then soaked in the extract solution obtained in step (2), drained, and stored in a ziplock bag.

[0010] In one embodiment of the present invention, the chitosan in step (1) is chitosan powder with a molecular weight of 5 kDa-500 kDa and a degree of deacetylation of 85%.

[0011] In one embodiment of the present invention, the acetic acid solution in step (1) is an aqueous solution of acetic acid, wherein the volume fraction of acetic acid is 0.5%-2.0%.

[0012] In one embodiment of the present invention, the mass proportion of glycerol in the chitosan solution in step (1) is 0.1%-1.0%.

[0013] In one embodiment of the present invention, the mass percentage of chitosan in the chitosan solution in step (1) is 0.5%-3.0%.

[0014] In one embodiment of the present invention, the mass percentage of citral in the citral nanoemulsion in step (1) is 0% to 15%; preferably 0% to 12%; more preferably 4% to 12%; and even more preferably 8%.

[0015] In one embodiment of the present invention, the mass ratio of citral to Tween 80 in step (1) is 3:2.

[0016] In one embodiment of the present invention, the mass ratio of the chitosan solution to the citral nanoemulsion in step (1) is 3:1.

[0017] In one embodiment of the present invention, the homogenization speed in step (1) is 8000 to 12000 rpm, and the time is 5 to 10 minutes.

[0018] In one embodiment of the present invention, the power of the ultrasound in step (1) is 200 to 500 W, and the time is 10 to 20 minutes.

[0019] In one embodiment of the present invention, the gluten in step (2) is gluten powder, and the main component of the extract solution is gliadin.

[0020] In one embodiment of the present invention, the volume fraction of the ethanol solution in step (2) is 70% to 80%.

[0021] In one embodiment of the present invention, the extraction in step (2) is performed at a rotation speed of 300 to 500 rpm for 8 to 10 hours.

[0022] In one embodiment of the present invention, the centrifugal speed in step (2) is 5000 to 8000 rpm, and the time is 10 to 20 minutes.

[0023] In one embodiment of the present invention, the mass ratio of gluten to glycerol in step (2) is 40:9.

[0024] In one embodiment of the present invention, the two immersion times in step (3) are 5 to 10 minutes.

[0025] Another object of the present invention is to provide an application of the above-mentioned method for preserving meat products in food preservation.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The method for preserving meat products of the present invention utilizes the opposite charges of gliadin (negatively charged) and chitosan (positively charged) in gluten extract to form an electrostatic interaction between the two; and both gliadin and chitosan are rich in hydroxyl groups and can form hydrogen bonds; the interaction between the layers driven by electrostatic interaction and hydrogen bonds is strong, so that the barrier property of the coating is high, thereby extending the shelf life of the meat products; on the 12th day of storage, the pH, juice loss rate and volatile basic nitrogen of the chicken of Example 3 were reduced by 16.72%, 9.44% and 71.47% respectively compared with those of Comparative Example 1;

[0028] (2) Compared with a single-layer coating liquid, the double-layer coating preservative liquid prepared by the present invention utilizes the hydrophobicity and physical barrier effect of the gliadin in the gluten extract to enable the slow release of citral, thereby avoiding the explosive release of active substances caused by direct blending; compared with the preparation of a double-layer coating liquid by an encapsulation system such as loaded nanoparticles and microcapsules, the present invention avoids the defects of complex encapsulation methods and low encapsulation rates, and can achieve a similar sustained-release effect only through layer-by-layer self-assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart;

[0030] Figure 2 Appearance diagram of fresh free-range chicken breast meat during storage after different treatments provided in Examples 1 to 4 and Comparative Examples 1 to 7. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in combination with the comparative examples and embodiments of the specification.

[0032] Example 1

[0033] A method for preserving meat products based on a self-assembled multifunctional double-layer coating, the method comprising the following steps:

[0034] (1) 25 g of chitosan powder (molecular weight 200 kDa) and 12.5 g of glycerol were dissolved in 2 liters of 1% (v / v) acetic acid solution, and stirred at 500 rpm for 4 hours using a magnetic stirrer. Then, 225 g of the solution was taken out and mixed with 75 g of deionized water to obtain a uniform chitosan solution;

[0035] (2) 100 g of gluten powder was dissolved in 2 liters of 70% (v / v) ethanol solution, extracted at 500 rpm for 8 hours, centrifuged at 5000 rpm for 20 minutes, and the supernatant was taken. 22.5 g of glycerol was added and mixed evenly to obtain a uniform extract solution;

[0036] (3) Cut fresh free-range chicken breast into uniform pieces, rinse with 4°C pre-cooled sterile water and absorb the surface moisture, soak in the chitosan solution obtained in step (1) for 5 minutes and then drain, then soak in the extract solution obtained in step (2) for 5 minutes and then drain, place in a self-sealing bag and store in a 4°C refrigerator.

[0037] Example 2

[0038] A method for preserving meat products based on a self-assembled multifunctional double-layer coating, the method comprising the following steps:

[0039] (1) 25 g of chitosan powder (molecular weight 200 kDa) and 12.5 g of glycerol were dissolved in 2 liters of 1% (v / v) acetic acid solution, and stirred at 500 rpm with a magnetic stirrer for 4 hours to obtain a uniform chitosan solution;

[0040] (2) dispersing 3 g of citral and 2 g of Tween 80 in 70 g of distilled water, homogenizing at 9500 rpm for 10 min and ultrasonicating at 250 watts for 20 min, respectively, to prepare a 4% (w / w) citral nanoemulsion; then adding 225 g of the chitosan solution prepared in step (1) and mixing well to obtain a 4% citral nanoemulsion-chitosan solution;

[0041] (3) 100 g of gluten powder was dissolved in 2 liters of 70% (v / v) ethanol solution, extracted at 500 rpm for 8 hours, centrifuged at 5000 rpm for 20 minutes, and the supernatant was taken. 22.5 g of glycerol was added and mixed evenly to obtain a uniform extract solution;

[0042] (4) Cut fresh free-range chicken breast into uniform pieces, rinse with 4°C precooled sterile water and dry the surface moisture, soak in the 4% citral nanoemulsion-chitosan solution obtained in step (2) for 5 minutes and then drain, then soak in the solution obtained in step (3) for 5 minutes and then drain, place in a ziplock bag and store in a 4°C refrigerator.

[0043] Example 3

[0044] A method for preserving meat products based on a self-assembled multifunctional double-layer coating, the method comprising the following steps:

[0045] (1) 25 g of chitosan powder (molecular weight 200 kDa) and 12.5 g of glycerol were dissolved in 2 liters of 1% (v / v) acetic acid solution, and stirred at 500 rpm with a magnetic stirrer for 4 hours to obtain a uniform chitosan solution;

[0046] (2) dispersing 6 g of citral and 4 g of Tween 80 in 65 g of distilled water, homogenizing at 9500 rpm for 10 min and ultrasonicating at 250 watts for 20 min, respectively, to prepare an 8% (w / w) citral nanoemulsion; then adding 225 g of the chitosan solution prepared in step (1) and mixing well to obtain an 8% citral nanoemulsion-chitosan solution;

[0047] (3) 100 g of gluten powder was dissolved in 2 liters of 70% (v / v) ethanol solution, extracted at 500 rpm for 8 hours, centrifuged at 5000 rpm for 20 minutes, and the supernatant was taken. 22.5 g of glycerol was added and mixed evenly to obtain a uniform extract solution;

[0048] (4) Cut fresh free-range chicken breast into uniform pieces, rinse with 4°C precooled sterile water and dry the surface moisture, soak in the 8% citral nanoemulsion-chitosan solution obtained in step (2) for 5 minutes and then drain, then soak in the extract solution obtained in step (3) for 5 minutes and then drain, place in a ziplock bag and store in a 4°C refrigerator.

[0049] Example 4

[0050] A method for preserving meat products based on a self-assembled multifunctional double-layer coating, the method comprising the following steps:

[0051] (1) 25 g of chitosan powder (molecular weight 200 kDa) and 12.5 g of glycerol were dissolved in 2 liters of 1% (v / v) acetic acid solution, and stirred at 500 rpm with a magnetic stirrer for 4 hours to obtain a uniform chitosan solution;

[0052] (2) dispersing 9 g of citral and 6 g of Tween 80 in 60 g of distilled water, homogenizing at 9500 rpm for 10 min and ultrasonicating at 250 watts for 20 min, respectively, to prepare a 12% (w / w) citral nanoemulsion; then adding 225 g of the chitosan solution prepared in step (1) and mixing well to obtain a 12% citral nanoemulsion-chitosan solution;

[0053] (3) 100 g of gluten powder was dissolved in 2 liters of 70% (v / v) ethanol solution, extracted at 500 rpm for 8 hours, centrifuged at 5000 rpm for 20 minutes, and the supernatant was taken. 22.5 g of glycerol was added and mixed evenly to obtain a uniform extract solution;

[0054] (4) Cut fresh free-range chicken breast into uniform pieces, rinse with 4°C pre-cooled sterile water and dry the surface moisture, soak in the 12% citral nanoemulsion-chitosan solution obtained in step (1) for 5 minutes and then drain, then soak in the extract solution obtained in step (2) for 5 minutes and then drain, place in a ziplock bag and store in a 4°C refrigerator.

[0055] Comparative Example 1

[0056] Use fresh free-range chicken breast meat, cut it into uniform pieces, rinse it with 4°C pre-cooled sterile water, absorb the surface moisture, put it in a ziplock bag and store it in a 4°C refrigerator.

[0057] Comparative Example 2

[0058] Use fresh free-range chicken breast meat, cut it into uniform pieces, rinse it with 4°C pre-cooled sterile water and absorb the surface moisture, wrap it with PE plastic wrap, put it in a self-sealing bag and store it in a 4°C refrigerator.

[0059] Comparative Example 3

[0060] A method for preserving meat products, the method comprising the following steps:

[0061] (1) 25 g of chitosan powder (molecular weight 200 kDa) and 12.5 g of glycerol were dissolved in 2 liters of 1% (v / v) acetic acid solution, and stirred at 500 rpm with a magnetic stirrer for 4 hours to obtain a uniform chitosan solution;

[0062] (2) Cut fresh free-range chicken breast into uniform pieces, rinse with 4°C pre-cooled sterile water and absorb the surface moisture, soak in chitosan solution for 5 minutes and drain, place in a ziplock bag and store in a 4°C refrigerator.

[0063] Comparative Example 4

[0064] A method for preserving meat products, the method comprising the following steps:

[0065] (1) 25 g of chitosan powder (molecular weight 200 kDa) and 12.5 g of glycerol were dissolved in 2 liters of 1% (v / v) acetic acid solution, and stirred at 500 rpm with a magnetic stirrer for 4 hours to obtain a uniform chitosan solution;

[0066] (2) dispersing 6 g of citral and 4 g of Tween 80 in 65 g of distilled water, homogenizing at 9500 rpm for 10 min and ultrasonicating at 250 watts for 20 min, respectively, to prepare an 8% (w / w) citral nanoemulsion; then adding 225 g of the chitosan solution prepared in step (1) and mixing well to obtain an 8% citral nanoemulsion-chitosan solution;

[0067] (3) Cut fresh free-range chicken breast into uniform pieces, rinse with 4°C pre-cooled sterile water and dry the surface moisture, soak in 8% citral nanoemulsion-chitosan solution for 5 minutes, drain, and store in a ziplock bag in a 4°C refrigerator.

[0068] Comparative Example 5

[0069] A method for preserving meat products, the method comprising the following steps:

[0070] (1) 100 g of gluten powder was dissolved in 2 liters of 70% (v / v) ethanol solution, extracted at 500 rpm for 8 hours, centrifuged at 5000 rpm for 20 minutes, and the supernatant was taken. 22.5 g of glycerol was added and mixed evenly to obtain a uniform extract solution;

[0071] (2) Cut fresh free-range chicken breast into uniform pieces, rinse with 4°C pre-cooled sterile water and absorb the surface moisture, soak in the extract solution for 5 minutes, drain, and store in a ziplock bag in a 4°C refrigerator.

[0072] Comparative Example 6

[0073] A method for preserving meat products, the method comprising the following steps:

[0074] (1) dissolving 25 g of chitosan powder and 12.5 g of glycerol in 2 L of 1% (v / v) acetic acid solution, stirring the mixture at 500 rpm for 4 hours using a magnetic stirrer to obtain a uniform chitosan solution;

[0075] (2) dispersing 6 g of citral and 4 g of Tween 80 in 65 g of distilled water, homogenizing at 9500 rpm for 10 min and ultrasonicating at 250 watts for 20 min, respectively, to prepare an 8% (w / w) citral nanoemulsion; then adding 225 g of the chitosan solution prepared in step (1) and mixing well to obtain an 8% citral nanoemulsion-chitosan solution;

[0076] (3) 100 g of gluten powder was dissolved in 2 liters of 70% (v / v) ethanol solution, extracted at 500 rpm for 8 hours, centrifuged at 5000 rpm for 20 minutes, and the supernatant was taken. 22.5 g of glycerol was added and mixed evenly to obtain a uniform extract solution;

[0077] (4) mixing 40 g of the 8% citral nanoemulsion-chitosan solution prepared in step (2) and 40 g of the extract solution prepared in step (3) to obtain an 8% citral nanoemulsion-chitosan-extract blended solution;

[0078] (5) Cut fresh free-range chicken breast into uniform pieces, rinse with 4°C pre-cooled sterile water and dry the surface moisture, soak in 8% citral nanoemulsion-chitosan-extract blend solution for 5 minutes, drain, and store in a ziplock bag in a 4°C refrigerator.

[0079] Comparative Example 7

[0080] A method for preserving meat products, the method comprising the following steps:

[0081] (1) dissolving 25 g of chitosan powder and 12.5 g of glycerol in 2 L of 1% (v / v) acetic acid solution, stirring the mixture at 500 rpm for 4 hours using a magnetic stirrer to obtain a uniform chitosan solution;

[0082] (2) dispersing 6 g of citral and 4 g of Tween 80 in 65 g of distilled water, homogenizing at 9500 rpm for 10 min and ultrasonicating at 250 watts for 20 min, respectively, to prepare an 8% (w / w) citral nanoemulsion; then adding 225 g of the chitosan solution prepared in step (1) and mixing well to obtain an 8% citral nanoemulsion-chitosan solution;

[0083] (3) 100 g of gluten powder was dissolved in 2 liters of 70% (v / v) ethanol solution, extracted at 500 rpm for 8 hours, centrifuged at 5000 rpm for 20 minutes, and the supernatant was taken. 22.5 g of glycerol was added and mixed evenly to obtain a uniform extract solution;

[0084] (4) Cut fresh free-range chicken breast into uniform pieces, rinse with 4°C pre-cooled sterile water and dry the surface moisture, soak in the extract solution obtained in step (3) for 5 minutes and then drain, then soak in the 8% citral nanoemulsion-chitosan solution obtained in step (2) for 5 minutes and then drain, place in a ziplock bag and store in a 4°C refrigerator.

[0085] Results Analysis

[0086] The fresh-keeping chicken breasts of Examples 1 to 4 and Comparative Examples 1 to 7 were sampled every 3 days until the 12th day and their sensory and physicochemical indices were tested.

[0087] 1. Determination of the apparent quality of fresh chicken breast during storage. The results are as follows: Figure 2 As shown:

[0088] from Figure 2 It can be seen from the results that the different treatment methods provided in Examples 1 to 4 and Comparative Examples 1 to 7 have caused varying degrees of decline in the apparent quality of fresh free-range chicken breast during storage. On the 0th day of storage, there was no significant difference in the sensory state of chicken in all groups, which indicates that the preservative solution did not cause a significant negative impact on the chicken breast. However, as the storage time increased, the surface of the chicken in each group gradually showed different degrees of accumulation of moisture and exudate. Overall, the preservation effect of the embodiments is better than that of the comparative examples, especially Examples 2 to 4.

[0089] 2. The effects of different treatments provided in Examples 1 to 4 and Comparative Examples 1 to 7 on the sensory evaluation of fresh free-range chicken breast during storage are shown in Table 1:

[0090] Table 1. Effects of different treatments on sensory evaluation of fresh free-range chicken breast during storage

[0091]

[0092] Note: The number of * represents the score of sensory evaluation.

[0093] The sensory evaluation mainly covers the evaluation of the color, smell and texture of chicken, which directly affect consumers' acceptance and purchasing decisions. As can be seen from the results in Table 1, on the 0th day of storage, the scores of the chicken nuggets in each group in terms of color, smell and texture were basically the same. However, with the extension of storage time, the sensory quality of each group of samples gradually declined to varying degrees, which was specifically manifested in the loss of bright color of chicken, increase of ammonia odor and deterioration of elasticity. After 6 days of storage, the sensory quality of the chicken nuggets in Comparative Examples 1 and 2 was significantly inferior to that in Examples 1 to 4, indicating that compared with no coating treatment and the use of PE cling film, the preservation method based on the self-assembled multifunctional double-layer coating of the present invention has significant advantages in slowing down the decline in the sensory quality of chicken.

[0094] 3. The effects of different treatments provided in Examples 1 to 4 and Comparative Examples 1 to 7 on the color difference of fresh chicken breast during storage are shown in Table 2:

[0095] Table 2. Effects of different treatments on color difference of fresh free-range chicken breast during storage

[0096]

[0097]

[0098] Note: The color difference values ​​of the differently treated chickens provided in Examples 1 to 4 and Comparative Examples 2 to 7 on day 0 were calculated based on Comparative Example 1, and significant differences were represented by capital letters; the color difference values ​​of the differently treated chickens provided in Examples 1 to 4 and Comparative Examples 1 to 7 on days 3 to 12 were calculated based on day 0, and significant differences were represented by lowercase letters.

[0099] The color difference change is closely related to the corruption of meat products and is an intuitive indicator for judging the freshness of chicken. In the early stage of storage (day 0), the color difference of the chicken of comparative example 1 and comparative example 2 is similar, because both groups have not been coated. The color difference of comparative examples 3 to 6 increases, and the reason is the color influence of chitosan, gluten extract and citral itself. For examples 1 to 4, as the concentration of citral increases, the color difference of chicken pieces also gradually increases. The extension of storage time makes the color difference of each group of chicken show an increasing trend to varying degrees, which is related to the corruption degree of chicken. Among all groups, the color difference change of the chicken of comparative example 2 is the most obvious, indicating that its corruption degree is the most serious.

[0100] 4. The effects of different treatments provided in Examples 1 to 4 and Comparative Examples 1 to 7 on the pH of fresh chicken breast during storage are shown in Table 3:

[0101] Table 3. Effects of different treatments on pH of fresh free-range chicken breast during storage

[0102]

[0103] pH value is an important indicator for measuring the quality and safety of chicken, and can reflect the freshness, microbial activity and overall quality changes of chicken during storage. On day 0, the pH value of chicken was 5.67. In the first 0 to 3 days of storage, the pH value of chicken decreased significantly, which is related to the anaerobic glycolysis of chicken after slaughter, which produced a large amount of lactic acid. However, as the storage time increases, the decomposition of protein in chicken produces a large amount of ammonia substances, causing the pH value to gradually increase. On the 12th day, the pH values ​​of chicken in Comparative Example 1 and Comparative Example 2 reached 6.82 and 6.50, respectively. In contrast, the pH value of chicken in other groups rose slowly, especially in Examples 2 to 4. This phenomenon is mainly attributed to the antibacterial effect of chitosan and citral in the edible film and the excellent barrier properties of the film.

[0104] 5. The effects of different treatments provided in Examples 1 to 4 and Comparative Examples 1 to 7 on the juice loss rate of fresh chicken breast during storage are shown in Table 4:

[0105] Table 4. Effects of different treatments on juice loss rate (%) of fresh free-range chicken breast during storage

[0106]

[0107] Juice loss rate is an important indicator for evaluating the fresh-keeping effect and meat quality changes of chicken. In the present invention, the juice loss rate of all groups gradually increases with the extension of storage time. This is mainly due to the decrease in the water holding capacity of chicken caused by protein hydrolysis, which causes juice exudation and reduces the quality of meat. On the 12th day of storage, the juice loss rates of the chicken in Comparative Example 1 and Comparative Example 2 reached 10.17% and 11.12%, respectively. In contrast, the juice loss rate of chicken treated with the preservative liquid coating was significantly reduced, especially in Examples 2 to 4, which may be related to the antibacterial and antioxidant properties of chitosan and cinnamaldehyde and the excellent barrier properties of the coating.

[0108] 6. The effects of different treatments provided in Examples 1 to 4 and Comparative Examples 1 to 7 on the volatile basic nitrogen of fresh chicken breast meat during storage are shown in Table 5:

[0109] Table 5. Effects of different treatments on volatile basic nitrogen (mg / 100g) of fresh free-range chicken breast during storage

[0110]

[0111] Volatile basic nitrogen (TVB-N) is one of the important indicators for evaluating the degree of corruption and freshness of chicken. TVB-N is mainly composed of amines, ammonia and other nitrogen volatile substances, which are usually produced by protein decomposition caused by microbial action or enzymatic reaction. As the storage time of chicken increases, microbial activity and protein decomposition intensify, and the TVB-N content will gradually increase. On day 0, the initial volatile basic nitrogen of chicken was 17.40 mg / 100 g sample. During storage, endogenous enzymes and microorganisms in chicken will decompose nitrogen-containing substances such as proteins and nucleic acids, resulting in a continuous increase in the volatile basic nitrogen content. The volatile basic nitrogen of the chicken in Comparative Examples 1 and 2 increased rapidly during storage. By the third day, its values ​​reached 26.19 mg / 100 g sample and 22.45 mg / 100 g sample, respectively, which is close to the limit of spoiled meat specified in the national standard (≥25 mg / 100 g sample). The volatile basic nitrogen of chicken in other groups increased significantly more slowly, approaching 20 mg / 100 g on the 12th day, far below the prescribed limit. This may be related to the antibacterial effect of chitosan and citral.

[0112] In summary, the method for preserving meat products based on self-assembled multifunctional double-layer coating of the present invention successfully delayed the decrease in pH value, increase in juice loss rate and increase in volatile basic nitrogen of fresh free-range chicken breast meat by virtue of its excellent barrier ability, antioxidant and antibacterial properties. This shows that the preservation method has the potential to effectively prevent oxidation and microbial contamination of perishable foods such as livestock and poultry meat, aquatic products, fruits and vegetables during transportation, storage and processing.

[0113] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preserving meat products based on self-assembled multifunctional double-layer coating, characterized in that: The method comprises the following steps: (1) dissolving chitosan and glycerol in an acetic acid solution to obtain a chitosan solution; dispersing citral and Tween 80 in water, homogenizing and ultrasonicating to obtain a citral nanoemulsion; and uniformly mixing the chitosan solution and the citral nanoemulsion to obtain a citral nanoemulsion-chitosan solution; (2) dissolving gluten in an ethanol solution, extracting and centrifuging, obtaining a supernatant and adding glycerol to obtain an extract solution; (3) The fresh meat product is first soaked in the citral nanoemulsion-chitosan solution obtained in step (1), drained, and then soaked in the extract solution obtained in step (2), drained, and stored in a ziplock bag.

2. The method according to claim 1, characterized in that The mass proportion of glycerol in the chitosan solution in step (1) is 0.1%-1.0%.

3. The method according to claim 1, characterized in that The mass proportion of chitosan in the chitosan solution in step (1) is 0.5%-3.0%.

4. The method according to claim 1, characterized in that: The mass percentage of citral in the citral nanoemulsion in step (1) is 0% to 15%.

5. The method according to claim 1, characterized in that The mass ratio of the chitosan solution to the citral nanoemulsion in step (1) is 3:

1.

6. The method according to claim 1, characterized in that The mass percentage of citral in the citral nanoemulsion in step (1) is 4% to 12%.

7. The method according to claim 1, characterized in that The chitosan in step (1) is chitosan powder with a molecular weight of 5kDa-500kDa.

8. The method according to claim 1, characterized in that The extraction in step (2) is performed at a rotation speed of 300 to 500 rpm and for a time of 8 to 10 hours.

9. The method according to claim 1, characterized in that: The two soaking times in step (3) are 5 to 10 minutes.

10. Use of the method according to any one of claims 1 to 9 in food preservation.

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