Aerogel fiber membrane with humidity response and capable of being used for food preservation and preparation method of aerogel fiber membrane

Abstract

The invention belongs to the technical field of food preservation, and particularly discloses an aerogel fiber membrane with humidity response and capable of being used for food preservation and a preparation method of the aerogel fiber membrane. The preparation method comprises the following steps: mixing a shell film-forming substance with a first solvent to obtain a shell spinning solution; mixing a core layer gel substance, a biological preservative, a cross-linking agent and a second solvent to obtain a core layer gel spinning solution; and then carrying out coaxial electrostatic spinning on the obtained shell layer spinning solution and core layer gel spinning solution at 40-60% RH to obtain the aerogel fiber membrane which has humidity response and can be used for food preservation. The core layer with the porous aerogel structure is prepared in one step, preparation is simple, industrialization is easy to achieve, and good application prospects are achieved; the aerogel fiber membrane not only can solve the problem of juice seepage in the storage process of fresh food, but also can perform humidity response to the environment and intelligently release an antibacterial agent in a controlled mode, growth and reproduction of dominant putrefying bacteria in the storage process of the fresh food are inhibited, and the preservation period is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of food preservation, and in particular to an aerogel fiber membrane with humidity response and capable of being used for food preservation, and a preparation method thereof. Background Art

[0002] With rising living standards, public demand for fresh foods such as organic fruits and vegetables, chilled meat, and live seafood continues to grow. Fresh seafood is rich in high-quality protein, vitamins, minerals, and essential polyunsaturated fatty acids. However, due to its high water activity, near-neutral pH, and rich nutritional profile, it is highly susceptible to spoilage during storage and transportation, resulting in significant economic losses. Packaging materials are crucial in preventing the deterioration of fresh foods during storage and transportation, and new, environmentally friendly packaging materials are gradually replacing traditional ones.

[0003] Biopreservatives are natural substances extracted from organisms such as animals, plants, and microorganisms that possess antimicrobial and antioxidant activity. They are highly safe and environmentally friendly and can be used as food additives. However, due to their instability and easy inactivation, they are difficult to use directly in food preservation and usually require encapsulation using other technologies to enhance their effectiveness. By utilizing the intelligent adsorption properties of packaging materials, coaxial electrospinning can be used to continuously prepare ultrafine fibers with a core-shell structure in a single step, encapsulating bioactive substances in the core layer and slowing their release. However, the thicker shell reduces the total release of active substances from the core layer.

[0004] However, the exudate produced during the storage and transportation of fresh aquatic and meat products, as well as the moisture generated by the respiratory metabolism of fruits and vegetables during storage and transportation, promotes the growth and reproduction of microorganisms, thereby deteriorating the quality of fresh food. Currently, few smart preservatives on the market release biopreservatives in response to exudate and moisture. Therefore, there is a need to utilize new technologies and simple preparation processes to develop a new humidity-responsive preservative material for food preservation, effectively improving the preservation of fresh food. Summary of the Invention

[0005] In view of this, the present invention provides a humidity-responsive aerogel fiber membrane that can be used for food preservation and a preparation method thereof, so as to solve the problems of low total release of active substances in existing methods and inability to regulate the release rate according to the state of fresh food.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a humidity-responsive aerogel fiber membrane that can be used for food preservation comprises the following steps:

[0008] 1) mixing a shell membrane-forming material and a first solvent to obtain a shell spinning solution;

[0009] mixing the core gel material, the biological preservative, the cross-linking agent and the second solvent to obtain a core gel spinning solution;

[0010] 2) coaxially electrospinning the obtained shell spinning solution and core gel spinning solution to obtain a humidity-responsive aerogel fiber membrane that can be used for food preservation;

[0011] The ambient humidity of the coaxial electrospinning is 40-60% RH.

[0012] Preferably, the mass concentration of the shell film-forming substance in the shell spinning solution in step 1) is 0.1-0.3 g / mL.

[0013] Preferably, the mass concentration of the core gel material in the core gel spinning solution in step 1) is 0.1-0.3 g / mL;

[0014] The mass concentration of the biological preservative in the core layer gel spinning solution is 0.01-0.1 g / mL;

[0015] The mass concentration of the crosslinking agent in the core layer gel spinning solution is 0.005-0.015 g / mL.

[0016] Preferably, the shell membrane-forming material comprises polysulfone;

[0017] The core layer gel material includes pullulan and / or zein;

[0018] The cross-linking agent is 1,1'-carbonyldiimidazole;

[0019] The first solvent and the second solvent independently include N,N-dimethylformamide and / or N,N-dimethylacetamide.

[0020] Preferably, the biological preservative includes one or more of lysozyme, thymol, carvacrol, natamycin, eugenol, thymol, methyl ferulate, resveratrol, tea polyphenols, spikenard essential oil, oregano essential oil, laurel essential oil, tea tree essential oil, osmanthus essential oil, lemon essential oil, nisin, clove leaf oil, mustard essential oil, malic acid, citronella essential oil, tannic acid, basil essential oil, litsea cubeba essential oil, rosemary essential oil, ginger essential oil, tsaoko essential oil, juniper essential oil, and ε-polylysine hydrochloride.

[0021] Preferably, when the core layer gel material is a mixture of pullulan and zein, the mass ratio of pullulan to zein is 1-5:1-3.

[0022] Preferably, in step 2), the flow rate of the shell layer spinning solution of the coaxial electrospinning is 2-4 mL / h, and the flow rate of the core layer gel spinning solution is 1.5-3 mL / h.

[0023] Preferably, the positive spinning voltage of the coaxial electrospinning in step 2) is 17-22 kV, the negative voltage is -1.6-1.9 kV, the roller receiving speed is 20-35 r / min, and the receiving distance is 15-25 cm.

[0024] Another object of the present invention is to provide an aerogel fiber membrane prepared by the preparation method and having humidity response and can be used for food preservation.

[0025] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention utilizes non-solvent-induced phase separation to induce a porous structure in the shell layer of the coaxial electrospun membrane. The core aerogel is sensitive to humidity changes, resulting in a stable, non-toxic, and highly safe aerogel fiber membrane. The porous structure of the shell layer improves the total release rate and release rate of the antimicrobial agent. The core aerogel swells and releases the antimicrobial agent upon increasing humidity, achieving humidity-responsive, intelligently controlled release. During the storage and transportation of fresh aquatic and meat products, exuded juices provide nutrients and moisture to microorganisms, promoting their growth and proliferation and accelerating food spoilage. During the storage and transportation of fresh fruits and vegetables, water vapor generated by respiratory metabolism promotes the growth and proliferation of microorganisms, promoting their spoilage. Therefore, during the storage and transportation of these fresh foods, when the humidity within the packaging increases, the aerogel within the fiber membrane swells due to water absorption, simultaneously releasing the biological preservative, providing antimicrobial and antioxidant benefits. The release rate and amount of the biological preservative are positively correlated with the ambient humidity.

[0027] 2. The present invention prepares an aerogel fiber membrane having a porous aerogel structure in the core layer and a porous aerogel structure in the shell layer in one step. The preparation is simple, easy to industrialize, and has good application prospects.

[0028] 3. The aerogel fiber membrane prepared by the present invention can not only solve the problem of juice leakage during the storage of fresh food, but also respond to the humidity of the environment and intelligently control the release of biological preservatives, inhibiting the growth and reproduction of dominant spoilage bacteria during the storage of fresh food and extending the shelf life of the food. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0030] Figure 1 The microscopic morphology of the aerogel fiber membrane prepared in Example 1 and Comparative Example 1 of the present invention is shown in FIG. Figure 1 (a1) is a scanning electron microscope image of the surface of the aerogel fiber membrane of Example 1. Figure 1 (a2) is a scanning electron microscope image of the cross section of the aerogel fiber membrane in Example 1. Figure 1 (a3) is a projection electron microscope image of the aerogel fiber membrane fiber of Example 1. Figure 1 (b1) is a scanning electron microscope image of the surface of the aerogel fiber membrane of Comparative Example 1. Figure 1 (b2) is a scanning electron microscope image of the fiber cross section of the aerogel fiber membrane of Comparative Example 1. Figure 1 (b3) is a projection electron microscope image of the aerogel fiber membrane fiber of Comparative Example 1;

[0031] Figure 2 This is a graph showing the water absorption rate of aerogel fiber membranes of Example 1 of the present invention and Comparative Example 1;

[0032] Figure 3 This is a graph showing the water retention rate of the aerogel fiber membrane prepared in Example 1 of the present invention at different temperatures;

[0033] Figure 4 This is the release kinetic curve of eugenol from the aerogel fiber membrane at different humidity in Example 1 of the present invention;

[0034] Figure 5 This is a comparison chart of the antibacterial properties of aerogel fiber membranes of Example 1 of the present invention and Comparative Example 1;

[0035] Figure 6 This is a graph showing changes in TVC values ​​of sea bass fillets during the preservation process of aerogel fiber membranes of Example 1 of the present invention and Comparative Example 1;

[0036] Figure 7 This is a graph showing changes in TVB-N values ​​of sea bass fillets during the preservation process of aerogel fiber membranes of Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0037] The present invention provides a method for preparing a humidity-responsive aerogel fiber membrane that can be used for food preservation, comprising the following steps:

[0038] 1) mixing a shell membrane-forming material and a first solvent to obtain a shell spinning solution;

[0039] mixing the core gel material, the biological preservative, the cross-linking agent and the second solvent to obtain a core gel spinning solution;

[0040] 2) The obtained shell spinning solution and core gel spinning solution are coaxially electrospun to obtain an aerogel fiber membrane with humidity response that can be used for food preservation.

[0041] In the present invention, the ambient humidity for the coaxial electrospinning is 40-60% RH, specifically 42% RH, 45% RH, 48% RH, 50% RH, 52% RH, 55% RH, or 58% RH.

[0042] In the present invention, the mass concentration of the shell film-forming substance in the shell spinning solution in step 1) is 0.1-0.3 g / mL, specifically 0.12 g / mL, 0.15 g / mL, 0.18 g / mL, 0.2 g / mL, 0.22 g / mL, 0.25 g / mL, or 0.28 g / mL.

[0043] In the present invention, the mass concentration of the core layer gel substance in the core layer gel spinning solution in step 1) is 0.1~0.3 g / mL, specifically 0.12 g / mL, 0.15 g / mL, 0.18 g / mL, 0.2 g / mL, 0.22 g / mL, 0.25 g / mL, and 0.28 g / mL.

[0044] In the present invention, the mass concentration of the biological preservative in the core layer gel spinning solution is 0.01-0.1 g / mL, specifically 0.02 g / mL, 0.04 g / mL, 0.05 g / mL, 0.06 g / mL, and 0.08 g / mL.

[0045] In the present invention, the mass concentration of the crosslinking agent in the core layer gel spinning solution is 0.005-0.015 g / mL, specifically 0.006 g / mL, 0.008 g / mL, 0.010 g / mL, 0.012 g / mL, or 0.014 g / mL.

[0046] In the present invention, the shell membrane-forming substance includes polysulfone.

[0047] In the present invention, the core layer gel material includes pullulan and / or zein.

[0048] In the present invention, the cross-linking agent is 1,1'-carbonyldiimidazole.

[0049] In the present invention, the first solvent and the second solvent independently include N,N-dimethylformamide and / or N,N-dimethylacetamide.

[0050] In the present invention, the biological preservative includes one or more of lysozyme, thymol, carvacrol, natamycin, eugenol, thymol, methyl ferulate, resveratrol, tea polyphenols, spikenard essential oil, oregano essential oil, laurel essential oil, tea tree essential oil, osmanthus essential oil, lemon essential oil, nisin, clove leaf oil, mustard essential oil, malic acid, citronella essential oil, tannic acid, basil essential oil, litsea cubeba essential oil, rosemary essential oil, ginger essential oil, tsaoko essential oil, juniper essential oil, and ε-polylysine hydrochloride.

[0051] In the present invention, when the core layer gel material is a mixture of pullulan and zein, the mass ratio of pullulan to zein is 1-5:1-3, preferably 2-5:1-2, and more preferably 5:1.

[0052] In the present invention, the flow rate of the shell spinning solution of the coaxial electrospinning in step 2) is 2~4 mL / h, specifically 2.2 mL / h, 2.4 mL / h, 2.5 mL / h, 2.6 mL / h, 2.8 mL / h, 3 mL / h, 3.2 mL / h, 3.4 mL / h, 3.5 mL / h, 3.6 mL / h, 3.8 mL / h; the flow rate of the core layer gel spinning solution is 1.5~3 mL / h, specifically 1.6 mL / h, 1.8 mL / h, 2 mL / h, 2.2 mL / h, 2.4 mL / h, 2.5 mL / h, 2.6 mL / h, 2.8 mL / h.

[0053] In the present invention, the positive spinning voltage of the coaxial electrospinning in step 2) is 17-22 kV, specifically 18 kV, 19 kV, 20 kV, 21 kV, and 22 kV; the negative voltage is -1.6-1.9 kV, specifically -1.65 kV, -1.70 kV, -1.8 kV, and -1.85 kV; the roller receiving speed is 20-35 r / min, specifically 22 r / min, 24 r / min, 25 r / min, 26 r / min, 28 r / min, 30 r / min, 32 r / min, and 34 r / min; and the receiving distance is 15-25 cm, specifically 16 cm, 17 cm, 18 cm, 19 cm, 20 cm, 21 cm, 22 cm, 23 cm, 24 cm, and 25 cm.

[0054] In the present invention, controlling the ambient humidity during the spinning process can control the solvent volatilization rate, affecting the size of the small droplets formed by condensation of water vapor, and thus controlling the porous structure of the fiber surface. The present invention also provides a humidity-responsive aerogel fiber membrane produced by the preparation method and used for food preservation.

[0055] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0056] Example 1

[0057] Polysulfone (MW ~80000, Shanghai Maclean Biochemical Technology Co., Ltd.) was dissolved in N,N-dimethylformamide (Shanghai Maclean Biochemical Technology Co., Ltd.) to prepare a shell spinning solution with a concentration of 0.2 g / mL. Pullulan (Shanghai Jizhi Biochemical Technology Co., Ltd.) and zein (Beijing Zhongcheng Jinnian Technology Co., Ltd.) at a mass ratio of 5:1 were dissolved in N,N-dimethylformamide to prepare a mixed solution with a concentration of 0.20 g / mL. Eugenol at a concentration of 0.04 g / mL and 1,1'-carbonyldiimidazole (Shanghai Dibai Biotechnology Co., Ltd.) at a concentration of 0.010 g / mL were then dissolved in this mixed solution to prepare the core gel spinning solution. The electrospinning operation was carried out using a coaxial electrospinning equipment. The process conditions were as follows: positive voltage 19.78 kV, negative voltage -1.80 kV, shell layer spinning solution flow rate 3 mL / h, core layer gel spinning solution 2 mL / h, roller receiving speed 30 r / min, receiving distance 20.0 cm, and ambient humidity 50% RH. A humidity-responsive aerogel fiber membrane that can be used for food preservation was produced.

[0058] The microstructure of the aerogel fiber membrane was characterized, and the results were as follows: Figure 1 As shown, the scanning electron microscope image of the surface of the aerogel fiber membrane of Example 1 is as shown Figure 1 As shown in (a1), the scanning electron microscope image of the cross section of the aerogel fiber membrane of Example 1 is as follows Figure 1 As shown in (a2), the projection electron microscope image of the aerogel fiber membrane fiber of Example 1 is as follows Figure 1 As shown in (a3) ​​in .

[0059] Comparative Example 1

[0060] The only difference between this comparative example and Example 1 is that eugenol is not added. Figure 1 As shown, the scanning electron microscope image of the surface of the aerogel fiber membrane of Comparative Example 1 is as shown Figure 1As shown in (b1), the scanning electron microscope image of the fiber cross section of the aerogel fiber membrane of comparative example 1 is as follows Figure 1 As shown in (b2), the projection electron microscope image of the aerogel fiber membrane fiber of comparative example 1 is as follows Figure 1 As shown in (b3) in Figure 1 It can be seen that the fibers of the aerogel fiber membrane prepared above all have a core-shell structure, and the surface of the shell layer has a porous structure, and the core layer presents a porous three-dimensional network gel structure. The addition of eugenol has little effect on the gel network structure.

[0061] The water absorption and water retention properties of the aerogel fiber membranes prepared in Example 1 and Comparative Example 1, as well as their antibacterial properties against Pseudomonas fragariae, a dominant spoilage bacteria in aquatic products, were measured. The specific testing methods are as follows:

[0062] (1) Water absorption and retention performance

[0063] Cut the aerogel fiber membrane into 1×1 cm 2 Place a small piece of the sample on a balance and weigh its mass m1. Immerse the sample in water until swelling equilibrium is reached. Wipe the surface and immediately weigh its mass m2 after absorption. The water absorption rate is calculated according to the following formula:

[0064]

[0065] Wherein, SD represents the water absorption rate, g / g; m1 represents the mass before water absorption, g; m2 represents the mass after water absorption, g.

[0066] Comparative Example 1 is recorded as 1, Example 1 is recorded as 2, and the test results are as follows Figure 2 shown.

[0067] Weigh the aerogel fiber membrane (Example 1) that has completely absorbed and swelled with water, record it as m3, and place it in a watch glass. Place it at different temperatures (4°C and 25°C) and weigh the remaining mass m4 at intervals. Continue measuring until the mass remains constant. The water retention rate is calculated as follows:

[0068]

[0069] Wherein, R represents the water retention rate, %; m3 represents the mass of the fully swollen aerogel fiber membrane, g; and m4 represents the mass of the aerogel fiber membrane after heat drying, g.

[0070] The water retention test results are as follows Figure 3 As shown, through Figure 2 and 3 It can be seen that the aerogel fiber membrane prepared above has good water absorption and water retention properties.

[0071] (II) Determination of sustained-release performance of eugenol in aerogel fiber membranes at different humidity

[0072] The aerogel fiber membrane prepared in Example 1 was placed in a desiccator at 30°C, containing saturated solutions of potassium carbonate, sodium chloride, and potassium sulfate, respectively, to simulate relative humidity environments of 50%, 75%, and 90%. A certain amount of the aerogel fiber membrane was removed at regular intervals and placed in anhydrous ethanol. After sonication for 30 minutes and 12 hours, the membrane was allowed to stand for 12 hours. The absorbance at 281 nm was measured, and the release of eugenol was calculated based on a standard curve for eugenol. A release curve was plotted and fitted with a curve equation.

[0073] The results are as follows Figure 4 As shown, the gel structure in the aerogel fiber membrane produced above undergoes changes such as volume expansion under different humidity environments. By controlling the release of the biopreservative in the material under different humidity environments, its antibacterial and preservation effects can be better exerted. Under high humidity, the gel network structure expands and its internal pores increase, providing a wider diffusion channel for the biopreservative, which is conducive to its release and effect.

[0074] (3) Antibacterial properties

[0075] Using Pseudomonas fragrans as a model bacterium (preserved in the laboratory), the bacterial suspension was adjusted to OD 595 ≈0.5; respectively set up a blank group (no treatment, recorded as CK), a control group (immersed in 0.10 g of aerogel fiber prepared in Comparative Example 1, recorded as 1) and an experimental group (immersed in 0.10 g of aerogel fiber prepared in Example 1, recorded as 2), and cultured them in a constant temperature shaker at 28 ° C. The OD of the bacterial suspension was measured. 595 value.

[0076] Antibacterial performance comparison chart Figure 5 As shown, through Figure 5 It can be seen that the antibacterial performance of Example 1 with eugenol added is better than that of Comparative Example 1 without eugenol added.

[0077] Fish fillets were placed in plastic boxes and set up as a blank group (untreated, designated CK), a control group (containing 2.0 g of aerogel fibers prepared in Comparative Example 1, designated 1), and an experimental group (containing 2.0 g of aerogel fibers prepared in Example 1, designated 2). The fish fillets were stored at 4°C. Every three days, 10.00 g of fish meat was collected and tested for total bacterial count (TVC) according to the "National Food Safety Standard - Food Microbiological Examination - Determination of Total Colony Count" (GB 4789.2-2022). Every three days, 5.00 g of fish meat was collected and tested for TVB-N (volatile basic nitrogen) according to the "First Method Semi-micro Nitrogen Determination Method" in GB 5009.228-2016.

[0078] TVC value changes as shown in the figure Figure 6 As shown, the TVB-N value change diagram is as follows Figure 7 shown; through Figure 6 and Figure 7 It can be seen that Example 1 in which eugenol is added has a good preservation effect on sea bass fillets.

[0079] Example 2

[0080] Polysulfone (MW ~80000, Shanghai Maclean Biochemical Technology Co., Ltd.) was dissolved in N,N-dimethylacetamide (Shanghai Maclean Biochemical Technology Co., Ltd.) to prepare a shell spinning solution with a concentration of 0.22 g / mL. Pullulan (Shanghai Jizhi Biochemical Technology Co., Ltd.) and zein (Beijing Zhongcheng Jinnian Technology Co., Ltd.) at a mass ratio of 3:1 were dissolved in N,N-dimethylacetamide to prepare a mixed solution with a concentration of 0.20 g / mL. Carvacrol at a concentration of 0.06 g / mL and 1,1'-carbonyldiimidazole (Shanghai Dibai Biotechnology Co., Ltd.) at a concentration of 0.010 g / mL were then dissolved in this mixed solution to prepare the core gel spinning solution. The electrospinning operation was carried out using a coaxial electrospinning equipment. The process conditions were positive voltage 21 kV, negative voltage -1.80 kV, shell layer spinning solution flow rate 3 mL / h, core layer gel spinning solution 2 mL / h, roller receiving speed 30 r / min, receiving distance 23.0 cm, and ambient humidity 55% RH. A humidity-responsive aerogel fiber membrane that can be used for food preservation was produced.

[0081] Example 3

[0082] Polysulfone (MW ~80,000, Shanghai Maclean Biochemical Technology Co., Ltd.) was dissolved in N,N-dimethylacetamide (Shanghai Maclean Biochemical Technology Co., Ltd.) to prepare a shell spinning solution with a concentration of 0.22 g / mL. Pullulan (Shanghai Jizhi Biochemical Technology Co., Ltd.) and zein (Beijing Zhongcheng Jinnian Technology Co., Ltd.) at a mass ratio of 1:1 were dissolved in N,N-dimethylacetamide to prepare a mixed solution with a concentration of 0.15 g / mL. Eugenol at a concentration of 0.02 g / mL and 1,1'-carbonyldiimidazole (Shanghai Dibai Biotechnology Co., Ltd.) at a concentration of 0.010 g / mL were then dissolved in this mixed solution to prepare the core gel spinning solution. Electrospinning was carried out using a coaxial electrospinning device. The process conditions were as follows: positive voltage 21 kV, negative voltage -1.80 kV, shell layer spinning solution flow rate 2.2 mL / h, core layer gel spinning solution 1.8 mL / h, roller receiving speed 24 r / min, receiving distance 18.0 cm, and ambient humidity 48% RH. A humidity-responsive aerogel fiber membrane that can be used for food preservation was produced.

[0083] In summary, it can be seen that the aerogel fiber membrane prepared by the technical solution of the present invention has stable physical and chemical properties, high safety, and good water absorption performance; it can be used for the preservation of fresh food, can better absorb the exudate generated during the storage of fresh food, intelligently control the release of biological preservatives, and extend the shelf life of food.

[0084] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0085] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a humidity-responsive aerogel fiber membrane that can be used for food preservation, characterized in that: The steps include: 1) mixing a shell membrane-forming material and a first solvent to obtain a shell spinning solution; mixing the core gel material, the biological preservative, the cross-linking agent and the second solvent to obtain a core gel spinning solution; 2) coaxially electrospinning the obtained shell spinning solution and core gel spinning solution to obtain a humidity-responsive aerogel fiber membrane that can be used for food preservation; The ambient humidity of the coaxial electrospinning is 40-60% RH.

2. The method for preparing a humidity-responsive aerogel fiber membrane for food preservation according to claim 1, characterized in that: The mass concentration of the shell film-forming substance in the shell spinning solution in step 1) is 0.1-0.3 g / mL.

3. The method for preparing a humidity-responsive aerogel fiber membrane for food preservation according to claim 2, characterized in that: The mass concentration of the core gel material in the core gel spinning solution in step 1) is 0.1-0.3 g / mL; The mass concentration of the biological preservative in the core layer gel spinning solution is 0.01-0.1 g / mL; The mass concentration of the crosslinking agent in the core layer gel spinning solution is 0.005-0.015 g / mL.

4. The method for preparing a humidity-responsive aerogel fiber membrane for food preservation according to any one of claims 1 to 3, characterized in that: The shell membrane-forming material includes polysulfone; The core layer gel material includes pullulan and / or zein; The cross-linking agent is 1,1'-carbonyldiimidazole; The first solvent and the second solvent independently include N,N-dimethylformamide and / or N,N-dimethylacetamide.

5. The method for preparing a humidity-responsive aerogel fiber membrane for food preservation according to claim 4, characterized in that: The biological preservative includes one or more of lysozyme, thymol, carvacrol, natamycin, eugenol, thymol, methyl ferulate, resveratrol, tea polyphenols, spikenard essential oil, oregano essential oil, laurel essential oil, tea tree essential oil, osmanthus essential oil, lemon essential oil, nisin, clove leaf oil, mustard essential oil, malic acid, citronella essential oil, tannic acid, basil essential oil, litsea cubeba essential oil, rosemary essential oil, ginger essential oil, tsaoko essential oil, juniper essential oil, and ε-polylysine hydrochloride.

6. The method for preparing a humidity-responsive aerogel fiber membrane for food preservation according to claim 5, characterized in that: When the core layer gel material is a mixture of pullulan and zein, the mass ratio of pullulan to zein is 1-5:1-3.

7. The method for preparing a humidity-responsive aerogel fiber membrane for food preservation according to claim 5 or 6, characterized in that: The flow rate of the shell layer spinning solution of the coaxial electrospinning in step 2) is 2-4 mL / h, and the flow rate of the core layer gel spinning solution is 1.5-3 mL / h.

8. The method for preparing a humidity-responsive aerogel fiber membrane for food preservation according to claim 7, characterized in that: The positive spinning voltage of the coaxial electrospinning in step 2) is 17-22 kV, the negative voltage is -1.6-1.9 kV, the roller receiving speed is 20-35 r / min, and the receiving distance is 15-25 cm.

9. An aerogel fiber membrane having humidity response and usable for food preservation, prepared by the preparation method according to any one of claims 1 to 8.

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