阅读说明：本技术 一种冷鲜肉托盘包装的抑菌吸水垫及其制备方法和应用 (Bacteriostatic water absorption pad for tray packaging of chilled fresh meat and preparation method and application thereof ) 是由 刘骞 于栋 孔保华 冯旸旸 徐敬欣 王浩 *** 于 2019-11-20 设计创作，主要内容包括：本发明公开了一种冷鲜肉托盘包装的抑菌吸水垫及其制备方法,该方法包括以下步骤：将丁香油乙醇溶液加入到聚乙烯醇和柠檬酸的混合溶液中,搅拌均匀后通过静电纺丝技术制备出聚乙烯醇基抑菌纳米纤维垫,之后对聚乙烯醇纳米纤维垫进行加热处理从而得到疏水性的聚乙烯醇基抑菌纳米纤维垫。根据本发明制备的纳米纤维垫具有较高的吸水性和抗菌性,其功能性优于目前现有的冷鲜肉吸水垫,这为食品活性包装提供了新的思路。此外,聚乙烯醇可完全降解,是一种环境友好型包装材料,符合绿色生态的发展趋势。本发明制备的疏水性聚乙烯醇基抑菌食品吸水垫可用在生鲜肉的包装盒中,不仅能提高冷鲜肉的感官特性还可以起到延长货架期的作用。(The invention discloses a bacteriostatic water absorption pad for tray packaging of chilled fresh meat and a preparation method thereof, wherein the method comprises the following steps: adding the clove oil ethanol solution into a mixed solution of polyvinyl alcohol and citric acid, uniformly stirring, preparing the polyvinyl alcohol-based antibacterial nanofiber pad by an electrostatic spinning technology, and then heating the polyvinyl alcohol-based antibacterial nanofiber pad to obtain the hydrophobic polyvinyl alcohol-based antibacterial nanofiber pad. The nanofiber mat prepared according to the invention has higher water absorption and antibacterial property, and the functionality of the nanofiber mat is superior to that of the existing cold fresh meat water absorption mat, so that a new idea is provided for active packaging of food. In addition, the polyvinyl alcohol can be completely degraded, is an environment-friendly packaging material, and accords with the development trend of green ecology. The hydrophobic polyvinyl alcohol-based bacteriostatic food water absorbent pad prepared by the invention can be used in a packaging box of fresh meat, can improve the sensory characteristics of the cold fresh meat and can also play a role in prolonging the shelf life.)

1. The bacteriostatic water absorption pad for tray packaging of the chilled fresh meat is characterized by comprising the steps of preparing a mixed solution of 5-12% of polyvinyl alcohol and 0.2-1.0% of citric acid, stirring until the mixed solution is completely dissolved, dropwise adding a clove oil solution prepared in advance into the polyvinyl alcohol solution, preparing a polyvinyl alcohol-based bacteriostatic nanofiber pad by an electrostatic spinning technology, heating the polyvinyl alcohol-based nanofiber pad, and finally preparing the bacteriostatic water absorption pad for the chilled fresh meat.

2. The bacteriostatic water-absorbing pad for tray packaging of chilled fresh meat according to claim 1, wherein the hydrophobicity of the polyvinyl alcohol nanofiber pad is improved by citric acid.

3. The bacteriostatic water-absorbing pad for the tray package of the chilled fresh meat as claimed in claim 1, wherein the mass fraction of the polyvinyl alcohol is 5-12%, and the mass fraction of the citric acid is 0.2-1.0%.

4. The method for preparing the bacteriostatic water-absorbing pad for the tray package of the chilled fresh meat as claimed in claim 1, wherein the method for preparing the bacteriostatic water-absorbing pad for the chilled fresh meat comprises the following steps:

(1) preparing a clove oil solution: accurately weighing clove oil and completely dissolving the clove oil in 1-5 mL of absolute ethyl alcohol for later use;

(2) preparing a polyvinyl alcohol solution: adding a certain amount of citric acid and polyvinyl alcohol into double distilled water, then placing the double distilled water into a magnetic water bath kettle, and continuously stirring the double distilled water and the polyvinyl alcohol at the temperature of 70-95 ℃ until the polyvinyl alcohol is completely dissolved, wherein the mass fraction percentage of the polyvinyl alcohol in the prepared polyvinyl alcohol solution is 5-12%, and the mass fraction percentage of the citric acid is 0.2-1.0%;

(3) preparation of the electrospinning solution: dropwise adding the clove oil solution prepared in the step (1) into the polyvinyl alcohol solution prepared in the step (2), and magnetically stirring for 7-12 hours to prepare an electrostatic spinning solution;

(4) adding the spinning solution obtained in the step (3) into a 10mL injector, wherein the dosage of the spinning solution is 10mL, and the parameters of the electrostatic spinning process are as follows: the voltage is 10-25 KV; the propelling speed is 0.2-1 mL/h; the receiving distance is 10-30 cm;

(5) and (4) placing the polyvinyl alcohol nanofiber mat obtained in the step (4) in an oven, and heating for 2-10 min at 120-180 ℃ to obtain the bacteriostatic water absorption mat for the chilled fresh meat.

5. The preparation method of the bacteriostatic water-absorbing pad for the tray package of the chilled fresh meat as claimed in claim 4, wherein in the step (1), the clove essential oil is added into 1-5 mL of absolute ethanol, and the mixture is shaken up to completely dissolve the clove oil.

6. The method for preparing the bacteriostatic water-absorbing pad for the tray package of chilled fresh meat according to claim 4, wherein in the step (5), the polyvinyl alcohol nanofiber pad is placed in an oven and heated at 120-180 ℃ for 2-10 min.

Technical Field

The invention relates to a bacteriostatic water absorption pad for tray packaging of chilled fresh meat, a preparation method and application thereof, and belongs to the field of food packaging.

Background

Along with the increasing development of national economy, the living standard of people is continuously improved, and the cold fresh meat in fine package is more and more favored by people. However, moisture and blood in the chilled meat may flow out during transportation, storage, sale, etc., which seriously affects the sensory quality of the chilled meat. At present, most of the water absorption pads on the market adopt non-woven fabrics and cotton fabrics to absorb water and blood flowing out from cold fresh meat, but the water absorption capability of the water absorption pads is insufficient and the growth and the propagation of microorganisms cannot be inhibited. Therefore, the development of the food water absorption pad with the bacteriostatic effect has very important practical significance.

Polyvinyl alcohol is a multifunctional polymer, has the advantages of chemical corrosion resistance, excellent physical property and gas barrier property, safety, no toxicity, easy degradation and the like, and is widely applied to industry. The polyvinyl alcohol nanofiber mat prepared by the electrostatic spinning technology has the advantages of high porosity and high specific surface area, and can quickly absorb moisture and release antibacterial substances for a long time. However, the polyvinyl alcohol nanofiber mat is easily dissolved in water, which limits its application in food packaging. The hydrophobic property of the polyvinyl alcohol nanofiber mat can be improved by adding citric acid into the polyvinyl alcohol solution and then heating the nanofiber mat to promote the esterification reaction between the citric acid and the nanofiber mat. The polyvinyl alcohol nanofiber pad does not have bacteriostatic activity per se, and antibacterial substances such as plant essential oil and the like are usually added into a polyvinyl alcohol solution to achieve the purpose of bacteriostasis. The clove oil is natural plant aromatic oil and has remarkable antibacterial and antioxidant properties, but the clove oil is volatile in air and not easy to dissolve in water, so that the utilization rate of the essential oil is greatly reduced. Therefore, the clove oil is embedded by using the electrostatic spinning fiber, so that the stability and the utilization rate of the clove oil are improved.

Therefore, the citric acid and the clove oil are added into the polyvinyl alcohol solution, so that the hydrophobicity of the polyvinyl alcohol nanofiber mat can be improved, and the function of bacteriostasis can be given to the polyvinyl alcohol nanofiber mat.

Disclosure of Invention

The invention aims to provide a bacteriostatic water absorption pad for tray packaging of chilled fresh meat and a preparation method and application thereof. The preparation method comprises the following steps: (1) preparing a clove oil solution: accurately weighing clove oil and completely dissolving the clove oil in 1-5 mL of absolute ethyl alcohol for later use.

(2) Preparing a polyvinyl alcohol solution: respectively adding citric acid and polyvinyl alcohol into double distilled water, heating in a water bath at 70-95 ℃ for 1h, and then magnetically stirring until the polyvinyl alcohol is completely dissolved, wherein the mass fraction percentage of the polyvinyl alcohol in the prepared polyvinyl alcohol solution is 5-12%, and the mass fraction percentage of the citric acid is 0.2-1.0%.

(3) Preparation of the electrospinning solution: dropwise adding the clove oil solution prepared in the step (1) into the polyvinyl alcohol solution prepared in the step (2), and magnetically stirring for 7-12 hours to prepare the electrostatic spinning solution.

(4) Adding the spinning solution obtained in the step (3) into a 10mL injector, wherein the dosage of the spinning solution is 10mL, and the parameters of the electrostatic spinning process are as follows: the voltage is 10-25 KV; the propelling speed is 0.2-1 mL/h; the receiving distance is 10-30 cm.

(5) Placing the polyvinyl alcohol nanofiber mat obtained in the step (4) in an oven under the conditions that: heating at 120-180 ℃ for 2-10 min to obtain the hydrophobic polyvinyl alcohol-based bacteriostatic food water absorbent pad.

The invention has the advantages that: the bacteriostatic water absorption pad for the tray package of the chilled fresh meat is made of biodegradable polyvinyl alcohol, and has the advantages of no toxicity, high biocompatibility, high safety and the like. Secondly, citric acid is used as a cross-linking agent, and the hydrophobicity of the polyvinyl alcohol nanofiber mat is improved through heating treatment, so that the polyvinyl alcohol nanofiber mat belongs to a cross-linking mode acceptable for green food. The clove oil used in the invention is natural plant essential oil, is extracted from the parts of buds, branches and leaves and the like of clove trees, and has high safety and high consumer acceptance. The hydrophobic polyvinyl alcohol-based bacteriostatic food water absorption pad prepared by the invention belongs to a nano material, has the advantages of high porosity, high specific surface area and low production cost. The water-absorbing pad has high water-absorbing capacity and can play a role in bacteriostasis, and the functionality of the water-absorbing pad is superior to that of the water-absorbing pad on the market at present.

The bacteriostatic water absorption pad packaged by the prepared chilled meat tray is used as a chilled meat water absorption pad.

Drawings

FIG. 1 scanning Electron microscopy of nanofiber mats and diameter distributions

FIG. 2 Water absorption Capacity diagram

FIG. 3 bacteriostatic circle of clove oil polyvinyl alcohol nanofiber mat

FIG. 4 Infrared Spectroscopy of polyvinyl alcohol nanofiber mats

Detailed Description

(1) Preparing a clove oil solution: adding oleum Caryophylli 0g, 0.08g, 0.16g, 0.24g, 0.32g, and 0.40g into 2mL anhydrous ethanol, stirring to dissolve completely, and keeping.

(2) Preparing a polyvinyl alcohol solution: respectively adding citric acid and polyvinyl alcohol into double distilled water, heating in a water bath at 90 ℃ for 1h, and then magnetically stirring until the polyvinyl alcohol is completely dissolved, wherein the mass fraction percentage of the polyvinyl alcohol in the prepared polyvinyl alcohol solution is 7.5%, and the mass fraction percentage of the citric acid is 0.6%.

(3) Preparation of the electrospinning solution: dropwise adding the clove oil solution prepared in the step (1) into the polyvinyl alcohol solution prepared in the step (2), wherein the mass fraction percentage of polyvinyl alcohol is 7.5%, the mass fraction percentage of citric acid is 0.6%, and magnetically stirring for 12h to prepare the electrostatic spinning solution.

(4) Adding the spinning solution obtained in the step (3) into a 10mL injector, wherein the dosage of the spinning solution is 10mL, and the parameters of the electrostatic spinning process are as follows: the voltage is 15 KV; the propelling speed is 0.5 mL/h; the receiving distance is 20 cm.

(5) Placing the polyvinyl alcohol nanofiber mat obtained in the step (4) in an oven under the conditions that: heating at 180 deg.C for 8 min. Obtaining the hydrophobic polyvinyl alcohol-based bacteriostatic food absorbent pad.

It can be seen from fig. 1 that the average diameter of the nanofibers tends to increase with the increase of the concentration of polyvinyl alcohol because the increase of the viscosity of the solution increases the entanglement between the molecular chains of polyvinyl alcohol, resulting in the increase of the diameter of the fibers. In particular, nanofibers of 5% polyvinyl alcohol contain many nodules and exhibit a spindle-type distribution as a whole due to a low solution viscosity resulting in a small degree of entanglement of molecular chains. In contrast, the morphology of the polyvinyl alcohol nanofiber containing clove oil is greatly different from that of a pure polyvinyl alcohol nanofiber, the uniformity is obviously poor, a plurality of nodules exist, and a plurality of clove oil exists at the positions where the nodules protrude. Therefore, experiments prove that the clove oil is successfully loaded into the polyvinyl alcohol nanofiber in the electrostatic spinning process, the fiber structure is stable, and the phenomenon of filament breakage is avoided.

As can be seen from FIG. 2, the water absorption capacity of the water absorption film on the market is 4.94g/g, and the water absorption capacity of the nanofiber mat is obviously improved after citric acid with different concentrations is added. The water absorption capacity of the nanofiber membrane containing 0.6% of citric acid is the strongest and is as high as 9.28 g/g. The addition of citric acid is proved to improve the water absorption of the nanofiber mat while improving the hydrophobicity.

Fig. 3 shows that the clove oil embedded nanofiber mat has significant bacteriostatic activity against staphylococcus aureus.

FIG. 4 shows that the PVA/citric acid nanofiber membrane is 3000-3500cm^-1An O-H bond stretching vibration absorption peak appears; 2941cm^-1C-H stretching vibration absorption peaks of alkyl appear; 1717cm^-1C ═ O stretching vibration absorption peak appears; 1435cm^-1Occurrence of CH₂An absorption peak; 1094cm^-1A C-O stretching vibration absorption peak appears. Compared with the polyvinyl alcohol nanofiber, the polyvinyl alcohol/citric acid nanofiber membrane has a new C ═ O functional group, and a C ═ O stretching vibration absorption peak can prove that the polyvinyl alcohol and the citric acid have an esterification reaction. The characteristic peak of clove oil has O-H stretching vibration absorption peak (3521 cm)^-1) (ii) a C-H stretching vibration absorption peak (2937 cm)^-1) (ii) a C ═ C vibration absorption peak (1514 cm)^-1). C-H stretching vibration absorption peak (2941 cm) of nanofiber embedded with essential oil compared with nanofiber not embedded with essential oil^-1) The clove oil has a C-H stretching vibration absorption peak (2937 cm)^-1) This indicates that the enhancement of the C-H stretching vibration absorption peak is due to the entrapment of clove oil, demonstrating the presence of clove oil in the polyvinyl alcohol nanofiber mat.