A kind of cold fresh chicken composite antibacterial film and preparation method thereof

Abstract

The present invention provides a method for preparing a cold fresh chicken composite antibacterial film, comprising the following steps: (1) mixing starch with sebacic acid, performing ultrasonic treatment, and obtaining a modified starch solution; (2) mixing an adhesive, ammonium bicarbonate and water to obtain a mixed solution; (3) mixing the modified starch solution and the mixed solution to use as a shell spinning solution; (4) ultrasonically treating a plant essential oil antibacterial agent to prepare a nanoemulsion as a core spinning solution; (5) preparing a film by coaxial electrospinning technology, and drying at 40°C. The present invention uses bean starch with a larger proportion of straight chain starch as a film-forming matrix, and is modified by sebacic acid to replace the hydrophilic groups in the starch, thereby improving the film-forming property, and the plant essential oil nanoemulsion has better dispersibility and stability. The fiber with a core-shell structure is prepared by coaxial electrospinning technology to wrap the antibacterial agent, reduce the loss of the antibacterial agent, enhance the antibacterial effect of the composite antibacterial film, and extend the storage time of chicken.

Description

Technical Field

[0001] The invention relates to the technical field of meat preservation, and in particular to a method for preparing a composite antibacterial film for chilled fresh chicken. Background Art

[0002] As people's living standards improve, the safety and nutritional characteristics of food have received widespread attention. Chicken is rich in essential amino acids, vitamins and minerals, and is increasingly favored by people, while also placing higher demands on its quality. Low-temperature storage of chicken can inhibit the fat oxidation process and microbial reproduction, and can maintain its original quality for a certain period of time. However, since a completely sanitary environment cannot be guaranteed during the slaughtering, transportation, and sales processes, as the storage time increases, microorganisms grow and reproduce, and fat is oxidized, causing the chicken to rot and deteriorate.

[0003] The degradable and antibacterial composite film prepared with natural biological materials as the matrix can inhibit the exchange of gas, water and solutes inside and outside the food and hinder the invasion of microorganisms on food, and has broad application prospects in food preservation. Bio-based degradable films generally use natural biological materials such as polysaccharides, proteins and lipids as the membrane matrix, and add natural antibacterial agents and antioxidants to make the film have better antiseptic ability, but it has certain deficiencies in terms of barrier and mechanical properties, and the antibacterial ability of natural antibacterial agents is significantly reduced due to their own properties and the influence of the external environment. Summary of the invention

[0004] Technical problem to be solved: In view of the above problems, the purpose of the present invention is to provide a method for preparing a composite antibacterial film for chilled fresh chicken, using bean starch with a higher content of amylose as the matrix, and modifying it by sebacic acid to enhance the hydrophobicity of the film and improve the film-forming property, and prepare a film with a core-shell fiber structure by coaxial electrospinning technology, wrapping the natural antibacterial agent in the fiber, reducing the loss and volatilization of the antibacterial agent, and enhancing the antibacterial and fresh-keeping effects.

[0005] Technical solution: A method for preparing a composite antibacterial film for chilled fresh chicken, which is carried out according to the following steps:

[0006] (1) weighing bean starch and sebacic acid solution, mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and subjecting the mixed solution to ultrasonic reaction to obtain a modified bean starch solution;

[0007] (2) uniformly mixing the adhesive, ammonium bicarbonate and water to obtain a mixed solution;

[0008] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0009] (4) Mix the plant essential oil antibacterial agent, Tween and water, mix them on a magnetic stirrer for 10 minutes, then use an ultrasonic cell disruptor to ultrasonically treat the mixed emulsion for 10 minutes at a frequency of 20 kHz and a power of 450 W, control the system temperature to 25°C by an ice water bath, and obtain a plant essential oil nanoemulsion as the core spinning solution;

[0010] (5) preparing a film by coaxial electrospinning technology, collecting the film on a metal plate, and then drying the film at 40° C. Further, the bean starch in step (1) includes mung bean starch and pea starch.

[0011] Furthermore, in step (1), the sebacic acid solution is prepared by dissolving sebacic acid in 80 v / v% ethanol solution, and the concentration of the sebacic acid solution is 0.1-0.3 wt.%.

[0012] Furthermore, in step (1), the ultrasonic treatment temperature is 55-85° C., and the ultrasonic treatment time is 60-120 min.

[0013] Furthermore, the adhesive in step (2) is one of methyl cellulose, hydroxypropyl methyl cellulose, sodium carboxymethyl cellulose, and hydroxyethyl cellulose.

[0014] Furthermore, in step (2), the mass ratio of the adhesive, ammonium bicarbonate and water is (0.5-1):(0.2-1.2):100.

[0015] Furthermore, in step (4), the plant essential oil antibacterial agent includes lemongrass essential oil, cinnamon essential oil, thyme essential oil and oregano essential oil, and the mass ratio of the plant essential oil antibacterial agent, Tween and water is (0.1-0.5):1.5:100.

[0016] Furthermore, in step (5), the coaxial electrospinning technical conditions are: spinning voltage is 20 kV, shell solution flow rate is 0.6 mL / h, core solution flow rate is 0.4 mL / h, and time is 5-8 h.

[0017] Beneficial effects:

[0018] 1. In the present invention, bean starch is selected. Compared with cereal starch and potato starch, bean starch has a larger proportion of amylose. The linear chain of amylose can form more hydrogen bonds, and its linear structure can form a double helix structure when retrograded, which is easier to recombine to form a film than amylopectin.

[0019] 2. In the present invention, sebacic acid can undergo an esterification reaction with starch to replace the hydrophilic group hydroxyl group in the starch, thereby improving the hydrophobicity of the starch-based film and enhancing the film-forming property of the starch.

[0020] 3. In the present invention, the plant essential oil antibacterial agent is prepared into a nanoemulsion by ultrasonic emulsification, which has the characteristics of small particle size, large specific surface area, good stability, uniform dispersion, high biological activity, etc., and can improve the shortcomings of plant essential oils being oily at room temperature, extremely poor water solubility, and strong volatility, reduce the volatilization of nitrogen-containing and sulfur-containing compounds with strong irritating odors in the essential oils, and delay the oxidation and polymerization chemical reactions of the essential oils affected by environmental factors such as light and heat, thereby improving the aroma quality and biological activity of the essential oils and enhancing the antibacterial property of the composite antibacterial film.

[0021] 4. The present invention adopts coaxial electrospinning technology to prepare a film with a core-shell fiber structure, and the plant essential oil antibacterial agent is wrapped in the core layer fiber. Ammonium bicarbonate is added at the same time. After thermal decomposition and volatilization, the shell layer fiber can have a porous structure. The film prepared from the porous core-shell fiber can reduce the loss and volatilization of the plant essential oil antibacterial agent and enhance the antibacterial and fresh-keeping effect. DETAILED DESCRIPTION

[0022] Example 1

[0023] The cold fresh chicken composite antibacterial film is prepared according to the following steps:

[0024] (1) weighing mung bean starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0025] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0026] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0027] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0028] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0029] Example 2

[0030] The cold fresh chicken composite antibacterial film is prepared according to the following steps:

[0031] (1) Weighing pea starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0032] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0033] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0034] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0035] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0036] Example 3

[0037] The cold fresh chicken composite antibacterial film is prepared according to the following steps:

[0038] (1) weighing mung bean starch and 0.1 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0039] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0040] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0041] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0042] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0043] Example 4

[0044] The cold fresh chicken composite antibacterial film is prepared according to the following steps:

[0045] (1) weighing mung bean starch and 0.3 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0046] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0047] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0048] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0049] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0050] Example 5

[0051] The cold fresh chicken composite antibacterial film is prepared according to the following steps:

[0052] (1) weighing mung bean starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0053] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.5:0.8:100 to obtain a mixed solution;

[0054] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0055] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0056] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0057] Example 6

[0058] The cold fresh chicken composite antibacterial film is prepared according to the following steps:

[0059] (1) weighing mung bean starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0060] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.8:0.8:100 to obtain a mixed solution;

[0061] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0062] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0063] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0064] Example 7

[0065] The cold fresh chicken composite antibacterial film is prepared according to the following steps:

[0066] (1) weighing mung bean starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0067] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.2:100 to obtain a mixed solution;

[0068] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0069] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0070] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0071] Example 8

[0072] The cold fresh chicken composite antibacterial film is prepared according to the following steps:

[0073] (1) weighing mung bean starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0074] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:1.2:100 to obtain a mixed solution;

[0075] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0076] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0077] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0078] Example 9

[0079] The cold fresh chicken composite antibacterial film is prepared according to the following steps:

[0080] (1) weighing mung bean starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0081] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0082] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0083] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.1:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min at a frequency of 20 kHz and a power of 450 W using an ultrasonic cell disruptor. The system temperature was controlled to 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0084] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0085] Example 10

[0086] The cold fresh chicken composite antibacterial film is prepared according to the following steps:

[0087] (1) weighing mung bean starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0088] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0089] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0090] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.5:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0091] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0092] Embodiment 11

[0093] The cold fresh chicken composite antibacterial film is prepared according to the following steps:

[0094] (1) weighing mung bean starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0095] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0096] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0097] (4) oregano essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0098] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0099] Comparative Example 1

[0100] The difference between this comparative example and Example 1 is that corn starch is used instead of mung bean starch. The specific preparation method is as follows:

[0101] (1) Weigh corn starch and 0.2 wt.% sebacic acid solution and mix them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and perform ultrasonic treatment at 80° C. for 90 min to obtain a modified starch solution;

[0102] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0103] (3) mixing the modified starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0104] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0105] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0106] Comparative Example 2

[0107] The difference between this comparative example and Example 1 is that sebacic acid is not added in step (1). The specific preparation method is as follows:

[0108] (1) weighing mung bean starch and mixing it with water to prepare a solution with a starch content of 10 wt.%, and ultrasonically treating it at 80° C. for 90 min to obtain a starch solution;

[0109] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0110] (3) mixing the bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0111] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0112] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0113] Comparative Example 3

[0114] The difference between this comparative example and Example 1 is that ammonium bicarbonate is not added in step (2). The specific preparation method is as follows:

[0115] (1) weighing mung bean starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0116] (2) mixing methyl cellulose and water in a mass ratio of 0.6:100 to obtain a mixed solution;

[0117] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0118] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min with an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W. The system temperature was controlled at 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution;

[0119] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0120] Comparative Example 4

[0121] The difference between this comparative example and Example 1 is that no antibacterial agent is added, and the specific preparation method is as follows:

[0122] (1) weighing mung bean starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0123] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0124] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a spinning solution;

[0125] (4) The film was prepared by electrospinning technology with a voltage of 20 kV, a solution flow rate of 0.6 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0126] Comparative Example 5

[0127] The difference between this comparative example and Example 1 is that the film is prepared by a casting method. The specific preparation method is as follows:

[0128] (1) weighing mung bean starch and 0.2 wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and ultrasonically treating the mixture at 80° C. for 90 min to obtain a modified bean starch solution;

[0129] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0130] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a premixed solution;

[0131] (4) Cinnamon essential oil, Tween and water were mixed in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min, and then the mixed emulsion was ultrasonically treated for 10 min at a frequency of 20 kHz and a power of 450 W using an ultrasonic cell disruptor, and the system temperature was controlled to 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion;

[0132] (5) The premixed liquid and the plant essential oil nanoemulsion were mixed evenly in a ratio of 2:1, and a film was prepared by a casting method. The film was collected on a metal plate and dried at 40°C.

[0133] Comparative Example 6

[0134] The difference between this comparative example and Example 1 is that the plant essential oil antibacterial agent is not prepared as a nanoemulsion, and the specific preparation method is as follows: (1) weighing mung bean starch and 0.2wt.% sebacic acid solution and mixing them thoroughly to prepare a mixed solution with a starch content of 10wt.%, and ultrasonically treating it at 80°C for 90min to obtain a modified bean starch solution;

[0135] (2) mixing methyl cellulose, ammonium bicarbonate and water in a mass ratio of 0.6:0.8:100 to obtain a mixed solution;

[0136] (3) mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to obtain a shell spinning solution;

[0137] (4) Mixing cinnamon essential oil, Tween and water in a mass ratio of 0.4:1.5:100 on a magnetic stirrer for 10 min to prepare a core spinning solution;

[0138] (5) The film was prepared by coaxial electrospinning technology with a voltage of 20 kV, a shell solution flow rate of 0.6 mL / h, a core solution flow rate of 0.4 mL / h, and a time of 5 h. The film was collected on a metal plate and then dried at 40 °C.

[0139] The various properties of Examples 1-11 and Comparative Examples 1-6 were measured according to the following methods:

[0140] Antibacterial performance: The size of the inhibition zone of common Salmonella, Escherichia coli, and Staphylococcus aureus in fresh cold chicken was used as an evaluation index. An indicator bacteria suspension with a concentration of 100 CFU / mL was prepared, and the indicator bacteria were cultured using an agar medium. The composite antibacterial film prepared by the present invention was cut into a circle with a diameter of 1 cm, attached to a plate containing bacteria, and cultured at 37°C for 48 hours. The diameter of the inhibition zone was observed and measured to determine the antibacterial performance of the composite antibacterial film.

[0141] Water permeability: Cut the composite fresh-keeping antibacterial agent into appropriate sizes, seal it in a container filled with anhydrous calcium chloride, place the container in an environment with constant relative humidity, and regularly measure the weight gain of the container filled with anhydrous calcium chloride. The water permeability is determined by the following formula:

[0142]

[0143] Where t is the interval between two times after the mass increment stabilizes, h; ΔM is the mass increment within t time, g; A is the water vapor permeability area of ​​the sample, m 2 .

[0144] Oxygen permeability: The composite fresh-keeping antibacterial agent was cut into a certain size, placed in an environment of 25°C and 53% RH, and the oxygen permeability was measured using Oxtran.

[0145] After treating chicken with the composite antibacterial films prepared in Examples 1-11 and Comparative Examples 1-6 for 14 days, various indicators of the chicken were measured: Volatile basic nitrogen (TVB-N value): the volatile basic nitrogen was determined by the "semi-micro nitrogen determination method" in GB 5009.228-2016.

[0146] Total colony count: Determine according to the method for total colony count in GB4789.2-2022 "Food Microbiology Examination".

[0147] Table 1 Diameter of inhibition zone (mm)

[0148] Escherichia coli salmonella Staphylococcus aureus Example 1 7.92 8.52 9.89 Example 2 7.85 8.48 9.85 Example 3 7.62 8.24 9.61 Example 4 7.88 8.45 9.76 Example 5 7.83 8.42 9.71 Example 6 7.61 8.39 9.66 Example 7 7.75 8.41 9.73 Example 8 7.81 8.37 9.72 Example 9 7.45 8.02 9.28 Example 10 7.88 8.46 9.81 Embodiment 11 7.86 8.61 9.88 Comparative Example 1 7.11 7.75 8.64 Comparative Example 2 7.02 7.62 8.52 Comparative Example 3 6.95 7.24 8.41 Comparative Example 4 6.87 7.21 8.35 Comparative Example 5 7.22 8.02 8.97 Comparative Example 6 7.58 8.21 9.32

[0149] As shown in Table 1, compared with the antibacterial films prepared in Comparative Examples 1-6, the composite antibacterial films prepared in Examples 1-11 have stronger antibacterial properties and have good inhibitory effects on the three pathogenic bacteria. In Comparative Example 4, no plant essential oil antibacterial agent was added, which greatly reduced the antibacterial properties of the composite antibacterial film. In Comparative Example 3, a plant essential oil antibacterial agent was added, but it may be due to the fact that no ammonium bicarbonate was added, the prepared core-shell fiber structure does not have a porous structure, and the plant essential oil antibacterial agent cannot be released, resulting in a reduction in the antibacterial properties of the composite antibacterial film. Example 1 and Comparative Example 6 have better inhibitory effects on the three pathogenic bacteria, which may be due to the direct addition of the plant essential oil antibacterial agent in Comparative Example 6, while Example 1 is prepared as a nanoemulsion, which has better dispersibility and stability, so the antibacterial effect of the composite antibacterial film is better.

[0150] Table 2 Water vapor transmission rate and oxygen transmission rate

[0151]

[0152] As shown in Table 2, Examples 1-11 use coaxial electrospinning technology to prepare composite antibacterial films. Compared with Comparative Example 5, they have larger void structures, so the water vapor permeability and oxygen permeability are larger. In Comparative Example 3, no ammonium bicarbonate is added, the porous structure is reduced, and the water vapor permeability and oxygen permeability are also reduced. In Comparative Examples 1 and 2, other starches are selected or the starch is not modified, which may cause poor film-forming properties, so the water vapor permeability and oxygen permeability are significantly increased, which is not conducive to the storage of fresh chicken.

[0153] Table 3 Chicken quality evaluation

[0154]

[0155] According to the provisions of GB 2707-2016 for fresh (frozen) livestock and poultry products, when TVB-N≤15mg / 100g, it can be considered as fresh meat, when 15mg / 100g≤TVB-N≤25mg / 100g, it can be considered as sub-fresh meat, and when TVB-N≥25mg / 100g, it can be considered as corrupted meat. As shown in Table 3, after chicken was treated with the composite antibacterial film prepared in Examples 1-11, its TVB-N was less than 15mg / 100g, and the total number of colonies was significantly lower than that of Comparative Examples 1-5, which proves that the composite antibacterial film prepared in the present invention has a good fresh-keeping and antibacterial effect on fresh chicken. Comparative Examples 1 and 2 provide convenient conditions for the growth and reproduction of microorganisms due to the large water vapor and oxygen permeability. Comparative Examples 3 and 5 do not have porous structures, and plant antibacterial essential oils cannot be released. No antibacterial agent is added in Comparative Example 4, so Comparative Examples 1-5 have poor antibacterial effects relative to Examples 1-11. The above embodiments are for a clear and complete description of the technical solution, and are partial embodiments of the present invention, rather than all embodiments. However, the embodiments of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations or simplifications made without departing from the spirit and principle of the present invention should all be equivalent replacement methods, and are all included in the protection scope of the present invention.

Claims

1. A method for preparing a composite antibacterial film for chilled fresh chicken, characterized in that: Follow these steps: (1) Weighing bean starch and sebacic acid solution, mixing them thoroughly to prepare a mixed solution with a starch content of 10 wt.%, and subjecting the mixed solution to ultrasonic reaction to obtain a modified bean starch solution; (2) uniformly mixing an adhesive, ammonium bicarbonate and water to obtain a mixed solution; the adhesive is one of methyl cellulose, hydroxypropyl methyl cellulose, sodium carboxymethyl cellulose and hydroxyethyl cellulose; the mass ratio of the adhesive, ammonium bicarbonate and water is (0.5-1): (0.2-1.2): 100; (3) uniformly mixing the modified bean starch solution and the mixed solution in a mass ratio of 1:1 to form a shell spinning solution; (4) Mixing a plant essential oil antibacterial agent, Tween and water, and mixing them on a magnetic stirrer for 10 min, then ultrasonically treating the mixed emulsion for 10 min using an ultrasonic cell disruptor at a frequency of 20 kHz and a power of 450 W, and controlling the system temperature to 25° C. by an ice-water bath to obtain a plant essential oil nanoemulsion as a core spinning solution; the plant essential oil antibacterial agent is any one of lemongrass essential oil, cinnamon essential oil, thyme essential oil and oregano essential oil, and the mass ratio of the plant essential oil antibacterial agent, Tween and water is (0.1-0.5):1.5:100; (5) The film was prepared by coaxial electrospinning technology, collected on a metal plate, and then dried at 40 °C.

2. The method for preparing a cold fresh chicken composite antibacterial film according to claim 1, characterized in that: In the step (1), the bean starch is mung bean starch or pea starch.

3. The method for preparing a cold fresh chicken composite antibacterial film according to claim 1, characterized in that: The method for preparing the sebacic acid solution in step (1) is to dissolve sebacic acid in 80 v / v% ethanol solution, and the concentration of the sebacic acid solution is 0.1-0.3 wt.%.

4. The method for preparing a cold fresh chicken composite antibacterial film according to claim 1, characterized in that: In the step (1), the ultrasonic treatment temperature is 55-85° C., and the ultrasonic treatment time is 60-120 min.

5. The method for preparing a cold fresh chicken composite antibacterial film according to claim 1, characterized in that: In the step (5), the coaxial electrospinning technical conditions are: spinning voltage is 20 kV, shell solution flow rate is 0.6 mL / h, core solution flow rate is 0.4 mL / h, and time is 5-8 h.

6. A cold fresh chicken composite antibacterial film prepared by the preparation method according to any one of claims 1 to 5.

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