Composite fiber membrane as well as preparation method and application thereof

Abstract

The invention provides a composite fiber membrane and a preparation method and application thereof, and belongs to the technical field of food fresh-keeping packaging, the preparation method of the composite fiber membrane comprises the following steps: (1) mixing gelatin and Arabic gum to form a gelatin-Arabic gum solution, adjusting the pH value to be acidic, standing, then sequentially adding nano-zinc oxide and origanum vulgare essential oil into the gelatin-Arabic gum solution, and uniformly stirring; performing homogenizing treatment to obtain origanum vulgare essential oil emulsion; (2) preparing a gelatin solution, mixing the gelatin solution with the origanum vulgare essential oil emulsion, and adding tween-80 to obtain an electrostatic spinning solution; and (3) injecting the electrostatic spinning solution into an injector, carrying out electrostatic spinning treatment, and collecting spinning fibers through receiving oil paper to obtain the composite fiber membrane. The obtained composite fiber membrane and UVC ultraviolet light can achieve a synergistic effect, origanum essential oil in the inner packaging layer is excited and released, and more effective bacteriostatic and antioxidant effects are achieved in the packaging and storage period of chilled fresh meat.

Description

Technical Field

[0001] The invention belongs to the technical field of food fresh-keeping packaging, and in particular relates to a composite fiber film and a preparation method and application thereof. Background Art

[0002] The transportation chain of meat and meat products has been extended with the rapid development of e-commerce and logistics industries, which has put higher requirements on preservation technology. Improving the packaging system to maintain the quality of meat has become an important challenge facing the food industry.

[0003] Most of the existing traditional food packaging uses plastic films such as polyethylene (PE), polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC) for pallet packaging, and combines singeing and disinfectant treatment to disinfect and sterilize cold fresh meat. The existing research on active packaging of meat and meat products uses preparation methods including extrusion, blow molding, casting, stretching, electrospinning, etc., and adds active ingredients (such as plant essential oils, plant extracts, etc.) in the form of blending, multi-layer composites, emulsions or microcapsule carriers. Among them, the active ingredients migrate from the packaging to the packaging headspace or the food surface through diffusion, thereby achieving the purpose of extending the shelf life.

[0004] However, the existing methods have the following main problems: (1) The existing traditional packaging is simple and passive, and the packaging materials are difficult to meet environmental protection requirements. In addition, the disinfection and sterilization methods may leave potential residues on the surface of fresh meat, leaving safety hazards; (2) The sustained release effect of active ingredients such as plant essential oils is poor, and it is difficult to accurately exert long-term antibacterial and antioxidant effects during the packaging and storage of meat and meat products. In addition, some packaging technologies that can achieve sustained release of essential oils have high equipment requirements and complicated processes, which are not conducive to industrial use.

[0005] The effect of food preservation is closely related to the release rate of active substances in the packaging. Improper protection or premature release of active ingredients will reduce their activity. Light stimulation is an effective method of non-contact stimulation and release. Among them, ultraviolet rays can not only sterilize food, but also promote the release of active ingredients, so that they can more effectively show their active efficacy in the packaging. However, this method has high requirements on the performance of cling film. Therefore, the development of suitable cling film has important application value. Summary of the invention

[0006] The present invention aims to develop a gelatin-based composite fiber membrane using electrospinning technology to provide a packaging system with sustained release capability and ultraviolet excitation characteristics. By combining ultraviolet irradiation treatment, the present invention can stimulate the release of active substances while carrying out the food sterilization step to maintain the quality of fresh meat during packaging and storage.

[0007] The present invention provides a method for preparing a composite fiber membrane, comprising the following steps: (1) mixing gelatin and gum arabic to form a gelatin-gum arabic solution, adjusting the pH value to be acidic, standing, and then sequentially adding nano zinc oxide and oregano essential oil thereto, and homogenizing to obtain an oregano essential oil emulsion; (2) preparing a gelatin solution, mixing it with the oregano essential oil emulsion, and adding Tween-80 to obtain an electrospinning solution; (3) The electrospinning solution is injected into a syringe, and after electrospinning, the spun fibers are collected by receiving oil paper to obtain a composite fiber membrane. Furthermore, in step (1), gelatin is mixed in the form of an acetic acid aqueous solution of gelatin; preferably, the concentration of the acetic acid aqueous solution of gelatin is 3-20% g / mL; more preferably, the volume concentration of the acetic acid aqueous solution is 20-65%; In step (1), gum arabic is mixed in the form of an ultrapure aqueous solution of gum arabic; preferably, the concentration of the ultrapure aqueous solution of gum arabic is 50% g / mL; In step (1), the mass ratio of gelatin to gum arabic is 2:1-4. Furthermore, in step (1), the concentration of the gelatin-gum arabic solution is 25% g / mL.

[0008] Further, in step (1), the pH value is adjusted to 3.5-3.9; More preferably, in step (1), the pH value is adjusted to 3.6. Furthermore, in step (1), the concentration of nano zinc oxide in the system is 1-3% g / mL; In step (1), the concentration of oregano essential oil in the system is 5-50% g / mL.

[0009] Further, in step (2), the concentration of the gelatin solution is 4-25% g / mL; In step (2), the concentration of Tween-80 in the system is 0.1% to 1% g / mL; In step (2), the volume ratio of the gelatin solution to the oregano essential oil emulsion is 1:0.5-1.5.

[0010] Further, in step (3), the high voltage of electrospinning is 16-20 kV, and the flow rate of electrospinning is 0.15-0.35 mL / h; Preferably, in step (3), the electrospinning high voltage is set to 18 kV and the spinning flow rate is set to 0.35 mL / h.

[0011] The present invention also provides a composite fiber membrane prepared by any of the above-mentioned preparation methods.

[0012] The present invention also proposes the use of any of the above composite fiber membranes in the storage and preservation of cold fresh meat. When in use, the composite fiber membrane needs to be irradiated with ultraviolet rays.

[0013] Furthermore, the ultraviolet light includes at least one of long-wave ultraviolet light, medium-wave ultraviolet light or short-wave ultraviolet light; preferably, the ultraviolet light is short-wave ultraviolet light; Preferably, the irradiation time is 1 to 10 hours. The present invention has the following advantages: The preparation method of the composite fiber membrane proposed by the present invention, first, gelatin and gum arabic are mixed in a suitable proportion to prepare a stable gelatin-arabic gum solution. Then, nano zinc oxide and oregano essential oil are added to the gelatin-arabic gum solution to obtain oregano essential oil emulsion. Since oregano essential oil is highly volatile, it has poor stability when used as a packaging active ingredient, and the formation of a gelatin-arabic gum composite emulsifier is conducive to enhancing the stability of the emulsion, which can effectively reduce the meaningless release of oregano essential oil. Then, using gelatin solution as a film-forming matrix, oregano essential oil emulsion is added thereto to prepare an electrostatic spinning solution, so that the emulsion droplets are distributed in the "structural network" composed of the gelatin solution for electrostatic spinning, which can effectively avoid the difficulty of forming spinning fibers due to electrostatic spinning with oregano essential oil emulsion alone. Finally, a composite fiber membrane with ultraviolet excitation characteristics is prepared by electrostatic spinning. The composite fiber membrane obtained by the present invention can synergize with ultraviolet light to excite and release the oregano essential oil in the inner layer of the packaging, and play a more effective antibacterial and antioxidant effect during the packaging and storage of cold fresh meat. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0015] Figure 1 is a Fourier infrared spectrum of the electrospun fiber membrane prepared in Test Example 1 of the present invention; Figure 2 This is the electronic nose radar image of the electrospun fiber membrane prepared in Test Example 2 of the present invention; Figure 3 is a graph showing the antioxidant properties of the electrospun fiber membrane prepared in Test Example 3 of the present invention; Figure 4 It is the stability of the oregano essential oil emulsion at different oregano essential oil emulsion EA concentrations in Test Example 4 of the present invention; Figure 5It is the spun fiber formed by the electrospinning solution GE-EA25 in Test Example 5 of the present invention; Figure 6 This is a graph showing the change in total colony count when the electrospun fiber membrane prepared in Experimental Example 1 of the present invention is used to preserve chilled fresh chicken breast. DETAILED DESCRIPTION

[0016] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0017] Oregano essential oil is a kind of plant essential oil, which has antioxidant and antibacterial effects and can be used for food preservation. Gelatin (GE) is a collagen hydrolyzate, which can be used as a natural food packaging material because of its wide source, good biocompatibility and biodegradability. Nano zinc oxide has low toxicity and can effectively kill bacteria. Ultraviolet light irradiation can promote it to produce free radicals, thereby achieving food sterilization and controllable excitation release of active ingredients simultaneously, maintaining meat quality. The inventor of the present application cleverly combined the above raw materials to prepare a packaging system with sustained release ability and ultraviolet excitation characteristics.

[0018] On the one hand, an embodiment of the present invention provides a method for preparing a composite fiber membrane, comprising the following steps: (1) mixing gelatin and gum arabic to form a gelatin-gum arabic solution, adjusting the pH value to be acidic, standing, and then sequentially adding nano zinc oxide and oregano essential oil thereto, and homogenizing to obtain an oregano essential oil emulsion; (2) preparing a gelatin solution, mixing it with the oregano essential oil emulsion, and adding Tween-80 to obtain an electrospinning solution; (3) The electrospinning solution is injected into a syringe, and after electrospinning, the spun fibers are collected by receiving oil paper to obtain a composite fiber membrane. In step (1) of the embodiment of the present invention, nano zinc oxide particles are first added to the gelatin-arabic gum solution, and after mixing, the gelatin-arabic gum can be combined to form a final emulsifier. Thereafter, oregano essential oil is added and homogenized, and the oregano essential oil can be wrapped in the interface layer composed of gelatin-arabic gum and nano zinc oxide to form an essential oil emulsion.

[0019] In one embodiment of the present invention, in step (1), gelatin (GE) is mixed in the form of an acetic acid aqueous solution of gelatin; preferably, the concentration of the acetic acid aqueous solution of gelatin is 3-20% g / mL; preferably, the concentration of the acetic acid aqueous solution of gelatin is 20% g / mL. Gelatin is a type of protein obtained by partial hydrolysis of collagen, and its raw material sources are mainly fish skin, pig skin, cow hide and cow bones, etc. "GB 6783-2013 National Food Safety Standard Food Additive Gelatin" stipulates that gelatin can be used as edible animal casings for meat products, and as an additive for a variety of foods. Therefore, compared with traditional packaging materials and some biodegradable polymer compounds (such as polyvinyl alcohol, etc.), gelatin used as packaging materials is more environmentally friendly and natural, has a shorter biodegradation cycle, and is more in line with green and sustainable production needs.

[0020] Furthermore, in step (1), the volume concentration of the acetic acid aqueous solution is 20-65%; further, in step (1), the volume concentration of the acetic acid aqueous solution is 40%.

[0021] In one embodiment of the present invention, in step (1), gum arabic (GA) is mixed in the form of an ultrapure aqueous solution of gum arabic; preferably, the concentration of the ultrapure aqueous solution of gum arabic is 50% g / mL.

[0022] Preferably, in step (1), the mass ratio of gelatin to gum arabic is 2:1-4; preferably, in step (1), the mass ratio of gelatin to gum arabic is 2:1.

[0023] Preferably, in step (1), the concentration of gelatin-arabic gum solution is 25% g / mL. In an embodiment of the present invention, in step (1), under acidic conditions of pH, gelatin and arabic gum can attract each other to form aggregates, wherein arabic gum can increase solution viscosity, and gelatin plays a role in reducing interfacial tension. Gelatin and arabic gum constitute a composite emulsifier, and the emulsion of suitable concentration formed by the two can enhance the stability of the emulsion, prevent the essential oil from being released at will, and thus improve its bioavailability. Therefore, compared to single gelatin or arabic gum as an emulsifier, the composite emulsifier formed by the gelatin-arabic gum solution of suitable concentration is more effective in improving the stability of the emulsion. Preferably, in step (1), the pH value is adjusted to 3.5 to 3.9. More preferably, in step (1), the pH value is adjusted to 3.6.

[0024] Preferably, in step (1), the standing temperature is room temperature and the standing time is 24 h.

[0025] Preferably, in step (1), the concentration of nano zinc oxide in the system is 1-3% g / mL; more preferably, in step (1), the concentration of nano zinc oxide in the system is 2% g / mL. GB 14880-2012 National Food Safety Standard for the Use of Food Nutrition Fortifiers stipulates that zinc oxide can be used as a source of zinc in food as a nutrition fortifier. Nanoparticles of zinc oxide, i.e., nano zinc oxide, are sensitive to light and can destroy the molecular structure after ultraviolet irradiation, promote the migration of active ingredients, and increase the release rate of essential oils in specific links.

[0026] Preferably, in step (1), the concentration of oregano essential oil in the system is 5-50% g / mL. Preferably, in step (1), the concentration of oregano essential oil in the system is 20% g / mL.

[0027] In step (2) of the embodiment of the present invention, gelatin solution and oregano essential oil emulsion are used to prepare the electrospinning solution.

[0028] In one embodiment of the present invention, in step (2), the concentration of the gelatin solution is 4-25% g / mL. Preferably, in step (2), the concentration of the gelatin solution is 20% g / mL. The gelatin solution is an acetic acid aqueous solution of gelatin; wherein the volume concentration of the acetic acid aqueous solution is 20-65%; preferably, in step (2), the volume concentration of the acetic acid aqueous solution is 40%; In one embodiment of the present invention, in step (2), the concentration of Tween-80 in the system is 0.1% to 1% g / mL. Preferably, in step (2), the concentration of Tween-80 in the system is 0.5% g / mL.

[0029] In one embodiment of the present invention, in step (2), the volume ratio of the gelatin solution to the oregano essential oil emulsion is 1:0.5-1.5. Preferably, in step (2), the volume ratio of the gelatin solution to the oregano essential oil emulsion is 1:1.

[0030] In the embodiment of the present invention, the gelatin in step (1) is mainly used as an emulsifier; in step (2), due to insufficient polymer molecular weight, electrostatic spinning using oregano essential oil emulsion alone will result in difficulty in forming spinning fibers, and electrostatic spraying will occur. Therefore, using gelatin solution as a film-forming matrix and adding the prepared oregano essential oil emulsion thereto is beneficial to increasing the molecular weight of the solution, and the emulsion droplets are distributed in the "structural network" formed by the gelatin solution for electrostatic spinning.

[0031] In step (3) of the embodiment of the present invention, the active substance is encapsulated by electrospinning technology. Compared with the traditional preparation methods such as casting and blow molding, the present invention adopts electrospinning technology to prepare the packaging film, which is easy to operate and the process is flexible and controllable.

[0032] In one embodiment of the present invention, in step (3), the high voltage of electrospinning is 16-20 kV, and the flow rate of electrospinning is 0.15-0.35 mL / h. Preferably, in step (3), the high voltage of electrospinning is set to 18 kV, and the spinning flow rate is set to 0.35 mL / h.

[0033] In one embodiment of the present invention, in step (3), during the electrospinning process, the syringe is connected to a 21G needle as a nozzle, the distance between the collector and the needle is set to 17.5 cm, the temperature is room temperature, and the ambient humidity is less than 50%. Preferably, in step (3), during the electrospinning process, the syringe is connected to a 21G needle as a nozzle, the distance between the collector and the needle is set to 17.5 cm, the temperature is room temperature, and the ambient humidity is less than 50%.

[0034] On the other hand, an embodiment of the present invention provides a composite fiber membrane prepared by any of the above-mentioned preparation methods.

[0035] On the other hand, an embodiment of the present invention further provides the use of any of the above-mentioned composite fiber membranes in the storage and preservation of cold fresh meat. When in use, the composite fiber membrane needs to be irradiated with ultraviolet rays.

[0036] The composite fiber membrane obtained in the embodiment of the present invention has ultraviolet response characteristics, and the combined ultraviolet irradiation treatment is beneficial to stimulating the release of essential oil in the film in a specific sterilization link. It has good sustained-release effect, antioxidant and antibacterial capabilities, is simple to operate, and has broad application prospects. It has practical application value for maintaining the quality of fresh cold meat and meat products.

[0037] In one embodiment of the present invention, the ultraviolet (UV) is mainly divided into three bands, namely long-wave ultraviolet (UVA), medium-wave ultraviolet (UVB) and short-wave ultraviolet (UVC).

[0038] In a preferred embodiment of the present invention, the ultraviolet rays are short-wave ultraviolet rays. In the embodiment of the present invention, short-wave ultraviolet rays (Ultraviolet C radiation, UVC) are also called deep ultraviolet bands, which have strong bactericidal ability. The ultraviolet wavelength range of the UVC band is between 200 and 280 nanometers, and the ultraviolet rays in this band have higher energy. At present, food factories often use this band for ultraviolet sterilization to disinfect the surface of food. Therefore, using the UVC band as an excitation light source is beneficial for enterprises to simultaneously carry out the excitation and release of active substances in conjunction with ultraviolet disinfection during actual application, so as to maintain product quality.

[0039] In one embodiment of the present invention, the irradiation time is 1 to 10 hours. More preferably, the irradiation time is 4 hours.

[0040] In one embodiment of the present invention, when in use, the composite fiber membrane is not in direct contact with the chilled fresh meat or is in direct contact with the chilled fresh meat. Preferably, the composite fiber membrane is not in direct contact with the chilled fresh meat.

[0041] In one embodiment of the present invention, the chilled fresh meat includes chicken, duck, pork, beef or mutton.

[0042] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[0043] Example 1 A method for preparing a composite fiber membrane comprises the following steps: (1) Gelatin (the concentration of gelatin in acetic acid aqueous solution is 20% g / mL, and the volume concentration of acetic acid aqueous solution is 40%) and gum arabic (the concentration of ultrapure gum arabic aqueous solution is 50% g / mL) are mixed in a mass ratio of 2:1 to form a gelatin-gum arabic solution with a concentration of 25% g / mL, the pH value is adjusted to 3.6, and after standing at room temperature for 24 h, 2% g / mL nano zinc oxide and 20% g / mL oregano essential oil are added in sequence, and the oregano essential oil emulsion (denoted as EA25) is obtained by homogenization; (2) Prepare a gelatin solution (the concentration of the acetic acid aqueous solution of gelatin is 20% g / mL, and the volume concentration of the acetic acid aqueous solution is 40%), mix the solution with the emulsion in step (1) at a volume ratio of 1:1, and then add 0.5% g / mL Tween-80 to obtain an electrospinning solution (denoted as GE-EA25). (3) The spinning solution obtained in step (2) was injected into the syringe, and the syringe was connected to a 21G needle as a nozzle. The electrospinning high voltage was set to 18 kV, the spinning flow rate was set to 0.35 mL / h, the distance between the collector and the needle was set to 17.5 cm, the spinning temperature was room temperature, and the ambient humidity was less than 50%. The spun fibers were collected by receiving oil paper to obtain the final composite fiber membrane.

[0044] Test Example 1 Structural characteristics of electrospun membranes Irradiation group: the composite fiber membrane obtained in Example 1 was irradiated with UVC for 4 h; Unirradiated group: composite fiber membrane obtained in Example 1; Experimental method: Fourier transform infrared spectrometer was used to characterize the structural characteristics of electrospun fiber membranes in the unirradiated group and the irradiated group. Band range: 4000 cm -1 ~500 cm -1 ; Resolution: 40 cm -1 ; The ambient conditions are room temperature. Results are shown in Figure 1 .

[0045] Experimental results: Figure 1As shown in the figure, UV irradiation can destroy hydrogen bonds. The broad peaks representing the stretching vibrations of hydroxyl and amino groups in the irradiated group shift slightly to the high wavenumber direction (3280.32 cm -1 →3280.81 cm -1 ). 2945 cm -1 The absorption peak at 1636 cm-1 is related to the asymmetric stretching vibration of the methylene group in oregano essential oil. The intensity of this absorption peak in the irradiated group is higher than that in the unirradiated group, indicating that after ultraviolet irradiation, oregano essential oil can escape from the inside of the electrospinning membrane to the surface. In addition, compared with the unirradiated group, the amide I band (1636 cm-1 -1 →1632 cm -1 ), amide II band (1545 cm -1 →1540 cm -1 ) and the symmetric stretching vibration of the carboxyl group (1401 cm -1 →1397 cm -1 ) decreased in absorption peak vibration frequency and weakened in molecular interaction. These changes indicate that UV light can destroy the fiber membrane structure and promote the release of essential oils.

[0046] Test Example 2 Electronic nose properties of electrospun membranes Irradiation group: the composite fiber membrane obtained in Example 1 was irradiated with UVC for 4 h; Unirradiated group: composite fiber membrane obtained in Example 1; Experimental method: The treated film samples (size 4cm) of the unirradiated group and the irradiated group were 2 The samples were heated in a water bath at 50°C for half an hour and then measured using a PEN3 electronic nose. The samples were heated for five minutes at intervals. In addition, oregano essential oil was measured in the same way to determine the flavor profile of the essential oil. Figure 2 .

[0047] Experimental results: Figure 2 As shown, the electronic nose flavor profiles of the irradiated group were consistent with those of the non-irradiated group and oregano essential oil, and the electronic nose values ​​of the irradiated group increased compared with those of the non-irradiated group, especially R2 (nitrogen oxides), R7 (inorganic sulfides) and R9 (aromatic components), which indicated that UV irradiation helped stimulate the release of flavor components in oregano essential oil.

[0048] Test Example 3 Antioxidant properties of electrospun membranes Irradiation group: the composite fiber membrane obtained in Example 1 was irradiated with UVC for 4 h; Unirradiated group: composite fiber membrane obtained in Example 1; Experimental methods: (1) 2,2-Azobis(3-ethylbenzothiazole-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging rate: The treated unirradiated and irradiated film samples (size 4 cm 2 The squares (with the shape of 20 μm) were placed in 4 mL of the diluted ABTS reaction solution and reacted for different time periods (0.67 h, 3 h, 6 h, 24 h, 48 h, 72 h, and 96 h) in the dark. The absorbance of the solution was measured at 734 nm, and the ABTS free radical scavenging rate was calculated as follows:

[0049] Where: A0 is the absorbance of blank solution; A1 is the absorbance of sample solution after reaction.

[0050] (2) 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) free radical scavenging rate: The treated film samples (size 4 cm) of the unirradiated group and the irradiated group were 2 The squares (with the shape of a square) were placed in 4 mL of 0.2 mM DPPH working solution, protected from light for different reaction times, the absorbance of the solution was measured at 517 nm, and the DPPH free radical scavenging rate was calculated according to the following formula:

[0051] Where: A0 is the absorbance of blank solution; A1 is the absorbance of sample solution after reaction.

[0052] Experimental results: Figure 3 As shown in (a), the DPPH free radical scavenging rate of the irradiated group and the non-irradiated group showed an upward trend with the increase of reaction time, among which the value of the irradiated group after 3 days of reaction was significantly higher than that of the non-irradiated group. Figure 3 (b) Demonstrates the ABTS free radical scavenging ability of the fiber membrane. The free radical scavenging rates of both the unirradiated and irradiated groups can reach over 80%, and the irradiated group changes slowly during the reaction time. The above results show that the fiber membrane made by electrospinning technology can exhibit excellent antioxidant properties and sustained release effects, and UVC irradiation can promote the dissipation of active substances. This finding is consistent with the electronic nose detection results of Test Example 2 ( Figure 2 ) are consistent.

[0053] Comparative Examples 1 to 3 Same as Example 1, except that In step (1), gelatin (the concentration of the acetic acid aqueous solution of gelatin is 3.4% g / mL, 7.1% g / mL, and 11.1% g / mL, respectively, and the volume concentration of the acetic acid aqueous solution is 40%) and gum arabic (the concentration of the ultrapure aqueous solution of gum arabic is 50% g / mL) are mixed in a mass ratio of 2:1 to form gelatin-gum arabic solutions with concentrations of 5% g / mL, 10% g / mL, and 15% g / mL, respectively, and the pH value is adjusted to 3.6. After standing at room temperature for 24 h, 2% g / mL nano zinc oxide and 20% g / mL oregano essential oil are added in sequence, and homogenization is performed to obtain oregano essential oil emulsions, which are respectively recorded as EA5, EA10, and EA15.

[0054] Comparative Example 4 Same as Example 1, except that In step (1), gelatin (the concentration of the acetic acid aqueous solution of gelatin is 15.3% g / mL, and the volume concentration of the acetic acid aqueous solution is 40%) and gum arabic (the concentration of the ultrapure aqueous solution of gum arabic is 50% g / mL) are mixed in a mass ratio of 2:1 to form a gelatin-arabic gum solution with a concentration of 20% g / mL, the pH value is adjusted to 3.6, and after standing at room temperature for 24 h, 2% g / mL nano zinc oxide and 20% g / mL oregano essential oil are added in sequence, and homogenization is performed to obtain an oregano essential oil emulsion, which is recorded as EA20.

[0055] The electrospinning solution obtained in step (2) is denoted as GE-EA20.

[0056] Comparative Example 5 Same as Example 1, except that In step (3), the spinning flow rate was set to 0.15 mL / h.

[0057] Comparative Examples 6-7 Same as Example 1, except that In step (3), the electrospinning high voltage is set to 16 kV and 20 kV respectively.

[0058] Test Example 4 Test the stability of the oregano essential oil emulsions obtained in Example 1 and Comparative Examples 1 to 4 Experimental method: The prepared oregano essential oil emulsion (EA5, EA10, EA15, EA20, EA25) was placed at room temperature for 72 h (3 d), and the emulsion was photographed every 24 h (1 d) to observe its stability. Figure 4 .

[0059] Experimental results: Figure 4It can be seen that EA5, EA10, and EA15 will show emulsion stratification and flocculation within 24 h of storage; when the EA concentration is further increased to 20 and 25% g / mL, the emulsion stability is significantly increased, and no essential oil is precipitated within 3 days of storage.

[0060] Test Example 5 Testing the spinning state of electrospinning solution for electrospinning Experimental method: The electrospinning solutions (GE-EA20 and GE-EA25) prepared in Example 1, Comparative Example 4, and Comparative Examples 5 to 7 were electrospun to observe the spinning state.

[0061] Experimental results: The oregano essential oil emulsion prepared with EA20 obtained in Comparative Example 4 was added to the gelatin solution to form an electrospinning solution. However, due to insufficient molecular weight and viscosity, spinning fibers were difficult to produce.

[0062] Depend on Figure 5 It can be seen that the GE-EA25 obtained in Example 1 can meet the experimental requirements due to the increase in the concentration of the composite emulsifier. Therefore, EA25 is finally preferably used to prepare the oregano essential oil emulsion, and mixed with the gelatin solution to form the final GE-EA25 spinning solution for electrospinning.

[0063] Table 1 shows the spinning states obtained under different electrospinning treatment conditions in Comparative Examples 5 to 7. Preferably, the electrospinning high voltage is 18 kV and the spinning flow rate is 0.35 mL / h.

[0064] Table 1 Selection of electrospinning solution

[0065] Test Example 1 Effect of electrospinning membrane on preservation of chilled chicken breast Irradiation group: the composite fiber membrane obtained in Example 1 was irradiated with UVC for 4 h; Unirradiated group: composite fiber membrane obtained in Example 1; Cling film: commercially available PE cling film; Cling film @UV 4h: Commercially available PE cling film was irradiated with UVC for 4 h.

[0066] Experimental method: The treated electrospun fiber membrane was used to package the fresh chicken breast on a tray and stored at 4°C to ensure that there was no direct contact between the two. In addition, the fresh chicken breast was packaged on a tray using commercially available PE cling film irradiated with UVC for 0 h and 4 h to compare with the prepared composite fiber membrane. The total number of colonies in chicken breast was determined in accordance with the national standard GB 4789.2-2022. The results are shown in Figure 6 .

[0067] Experimental results: Figure 6 As shown in the figure, chicken breasts were packaged with commercial cling film in the irradiated group, the non-irradiated group, and UVC irradiated for 0 h and 4 h. After storage for 6 days, the total colony count in the irradiated group was significantly lower than that in the other three groups, indicating that the oregano essential oil in the prepared composite fiber membrane can be released under ultraviolet light and can exert an antibacterial effect without direct contact with food, reaching and exceeding the preservation effect of commercial cling film.

[0068] In summary, the prepared composite fiber film has an obvious sustained-release effect during packaging and storage, and the irradiated group has stronger flavor release and antioxidant capacity than the non-irradiated group. In addition, compared with the non-irradiated group and the commercially available cling film irradiated with UVC for 0 h and 4 h, the irradiated group showed a longer-lasting antibacterial and fresh-keeping effect on chilled chicken breast, and has great potential for targeted and precise release of active ingredients and maintenance of product quality during the packaging and storage of chilled meat products.

[0069] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a composite fiber membrane, characterized in that: The steps include: (1) mixing gelatin and gum arabic to form a gelatin-gum arabic solution, adjusting the pH value to be acidic, standing, and then sequentially adding nano zinc oxide and oregano essential oil thereto, and homogenizing to obtain an oregano essential oil emulsion; (2) preparing a gelatin solution, mixing it with the oregano essential oil emulsion, and adding Tween-80 to obtain an electrospinning solution; (3) The electrospinning solution is injected into a syringe, and after electrospinning, the spun fibers are collected by receiving oil paper to obtain a composite fiber membrane.

2. The preparation method according to claim 1, characterized in that: In step (1), gelatin is mixed in the form of an acetic acid aqueous solution of gelatin; preferably, the concentration of the acetic acid aqueous solution of gelatin is 3-20% g / mL; more preferably, the volume concentration of the acetic acid aqueous solution is 20-65%; In step (1), gum arabic is mixed in the form of an ultrapure aqueous solution of gum arabic; preferably, the concentration of the ultrapure aqueous solution of gum arabic is 50% g / mL; In step (1), the mass ratio of gelatin to gum arabic is 2:1-4.

3. The preparation method according to claim 1 or 2, characterized in that: In step (1), the concentration of the gelatin-gum arabic solution is 25% g / mL.

4. The preparation method according to claim 1, characterized in that: In step (1), the pH value is adjusted to 3.5-3.9; More preferably, in step (1), the pH value is adjusted to 3.

6.

5. The preparation method according to claim 1, characterized in that: In step (1), the concentration of nano zinc oxide in the system is 1-3% g / mL; In step (1), the concentration of oregano essential oil in the system is 5-50% g / mL.

6. The preparation method according to claim 1, characterized in that: In step (2), the concentration of the gelatin solution is 4-25% g / mL; In step (2), the concentration of Tween-80 in the system is 0.1% to 1% g / mL; In step (2), the volume ratio of the gelatin solution to the oregano essential oil emulsion is 1:0.5-1.

5.

7. The preparation method according to claim 1, characterized in that: In step (3), the high voltage of electrospinning is 16-20 kV, and the flow rate of electrospinning is 0.15-0.35 mL / h; Preferably, in step (3), the electrospinning high voltage is set to 18 kV and the spinning flow rate is set to 0.35 mL / h.

8. The composite fiber membrane prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the composite fiber membrane according to claim 8 in the storage and preservation of cold fresh meat, characterized in that: When in use, the composite fiber membrane needs to be irradiated with ultraviolet rays.

10. The use according to claim 1, characterized in that: The ultraviolet rays include at least one of long-wave ultraviolet rays, medium-wave ultraviolet rays or short-wave ultraviolet rays; preferably, the ultraviolet rays are short-wave ultraviolet rays; Preferably, the irradiation time is 1 to 10 hours.

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