Temperature response type antibacterial packaging fresh-keeping film loaded with cinnamon essential oil as well as preparation method and application of temperature response type antibacterial packaging fresh-keeping film

Abstract

The invention discloses a temperature response type antibacterial packaging fresh-keeping film as well as a preparation method and application thereof, and belongs to the technical field of fruit packaging fresh-keeping. The preparation method comprises the following steps: mixing polyvinyl alcohol (PVA) and polyvinyl caprolactam (PNVCL), stirring and dissolving to obtain a shell solution; the preparation method comprises the following steps: mixing polylactic acid (PLA) and hexafluoroisopropanol, stirring and dissolving to obtain a PLA solution, adding cinnamon essential oil (CEO), and uniformly stirring to obtain a core layer solution; degassing and standing; and performing coaxial electrostatic spinning on the shell layer solution and the core layer solution to obtain the fresh-keeping film. The fresh-keeping film has good hydrophilicity, antibacterial property and oxidation resistance, can intelligently respond to environment temperature change to realize CEO slow release, can effectively delay softening, decaying and deterioration of the picked waxberries, and remarkably prolongs the fresh-keeping period.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fruit packaging, in particular to a temperature-responsive antibacterial packaging preservation film loaded with cinnamon essential oil and a preparation method and application thereof. BACKGROUND

[0002] Myrica rubra belongs to the Myricaceae family and is a characteristic berry originating from subtropical regions. In China, the history of wild Myrica rubra can be traced back more than 7000 years, and the history of artificial cultivation has exceeded 2000 years. Myrica rubra is favored by consumers for its bright color, unique flavor, and rich nutritional value. Since the outer surface of Myrica rubra has no peel, the fruit is easily damaged mechanically, which accelerates the invasion of microorganisms, leading to postharvest Myrica rubra being prone to corruption and deterioration. Therefore, extending the shelf life of postharvest Myrica rubra is the focus of current producers and consumers.

[0003] Fruit preservation is crucial for reducing losses during production and transportation, so it is particularly important to find a natural and green fruit preservative. Essential oils are aromatic oil-like liquids extracted from various parts of plants such as flowers, flower buds, seeds, leaves, bark, fruits, and roots. They are of great interest due to their antibacterial properties and biodegradability. Cinnamon essential oil (CEO) is a natural essential oil obtained by distilling cinnamon leaves, and its main component is cinnamaldehyde, which has excellent antibacterial activity. However, the volatility and degradability of CEO pose challenges for its application in fruit preservation.

[0004] To address the above problems, the temperature-sensitive properties of poly-N-vinylcaprolactam (PNVCL) provide a solution for the controlled release of CEO. PNVCL is a temperature-responsive polymer with the advantages of low cytotoxicity, high biocompatibility, and a lower critical solution temperature (LCST) in water between 32℃ and 35℃. PNVCL is also a typical polyvinylamide with hydrophilic amide groups and hydrophobic carbon-carbon main chains. The temperature-sensitive properties of PNVCL allow its structure to change at different environmental temperatures, thereby achieving controlled release of the contents.

[0005] Based on the above background and material properties, a preparation method and application of a temperature-responsive antibacterial nanofiber preservation film are proposed. SUMMARY

[0006] The application aims to provide a packaging fresh-keeping film with temperature response and antibacterial activity, which is used for postharvest packaging fresh-keeping of waxberries, and the main content is that a core layer is prepared by taking polylactic acid (PLA) as a film-forming base material and taking cinnamon essential oil (CEO) as an antibacterial component; a shell layer is prepared by taking polyvinyl alcohol (PVA) as a film-forming base material and taking poly (N-vinyl caprolactam) (PNVCL) as a temperature sensor, and a packaging film with temperature response and antibacterial performance is prepared by a coaxial electrospinning technology, so that the packaging film has a long-lasting fresh-keeping effect during postharvest storage of the waxberries.

[0007] The application achieves the above-mentioned purpose by the following technical scheme:

[0008] (1) PLA and PVA are taken as film-forming base materials;

[0009] (2) A temperature-sensitive polymer PNVCL is additionally added to the film-forming material;

[0010] (3) An antibacterial agent CEO is added to the film-forming material;

[0011] (4) A coaxial electrospinning technology is adopted to prepare a temperature-sensitive packaging film loaded with the CEO;

[0012] (5) Multiple characterization technologies are adopted to prove that the packaging film has excellent performance;

[0013] (6) The prepared temperature-responsive antibacterial packaging fresh-keeping film loaded with the CEO has temperature sensitivity due to the presence of the PNVCL and has antibacterial property due to the presence of the CEO, so that the effect of slow release fresh-keeping under variable temperature can be achieved.

[0014] The preparation method of the temperature-responsive antibacterial packaging fresh-keeping film loaded with the CEO comprises the following steps:

[0015] (1) PLA / CEO core layer spinning solution is prepared: 0.6g of PLA is dissolved in 5mL of hexafluoroisopropanol to obtain a PLA solution (12% v / v), the prepared PLA solution is taken, 200ul of CEO (4% v / v) is added into the PLA solution, and the PLA / CEO spinning solution is obtained by fully mixing the PLA solution through a magnetic stirrer.

[0016] (2) PVA / PNVCL shell layer spinning solution is prepared: 0.1g of PVA and 0.2g of PNVCL (v:v=5:1) are dissolved in 10mL of pure water to obtain the PVA / PNVCL spinning solution.

[0017] (3) Preparation of temperature-sensitive coaxial electrospun packaging film loaded with CEO: The prepared PLA / CEO core spinning solution was injected into a 5 mL syringe pump, and the PVA / PNVCL shell solution was injected into a 10 mL syringe pump for coaxial electrospinning. The feed rate of the pump was set to 0.3 mL·h. -1 0.6 mL·h -1 The distance between the needle and the flywheel collector (300r / min) is 15cm, and the applied voltage is 18kV, thus obtaining the temperature-sensitive packaging preservation film with the load CEO (shell: PVA / PNVCL + core: PLA / CEO, hereinafter referred to as: PP / PC-4, where the number represents the percentage of essential oil content in the core layer solution).

[0018] The temperature-responsive antibacterial preservative film obtained by the above preparation method has a significant preservation effect in the post-harvest storage of bayberries when used as a packaging material.

[0019] The beneficial effects of this invention are as follows:

[0020] (1) The temperature-responsive antibacterial packaging and preservation film (PP / PC-4) loaded with CEO described in this invention is prepared using coaxial electrospinning technology. Cold field scanning electron microscopy reveals a smooth and porous nanofiber network structure on its surface, with the average diameter of the nanofibers reaching a maximum of 864.47±21.20 nm. This core-shell structure can effectively encapsulate CEO, preventing its degradation and facilitating long-term preservation of bayberries and extending their shelf life.

[0021] (2) The PP / PC-4 membrane with a CEO load described in this invention has good mechanical properties, with tensile strength and maximum force reaching 5.26±0.72MPa and 3.08±0.31N respectively, which is crucial for maintaining the integrity and sustainability of bayberry after harvest.

[0022] (3) The PP / PC-4 film with a load of CEO described in this invention has good thermal stability and is suitable for use in the post-harvest environment of bayberry at room temperature and high temperature, thus avoiding deformation and rupture that would lead to preservation failure.

[0023] (4) The PP / PC-4 membrane loaded with CEO described in this invention has good antibacterial activity and the inhibition diameter against Aspergillus niger reaches 18.92±0.58mm. It can effectively delay the quality deterioration of berries such as bayberries after harvest, such as softening, rotting and spoilage, and extend their shelf life to 4 days.

[0024] (5) The film-forming material PLA and the additives PNVCL and CEO used in the PP / PC-4 film of the present invention are non-toxic, harmless and biodegradable, have food safety, and are environmentally friendly materials that will not harm the environment. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art or ordinary skills, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram illustrating the production process and application principle of the temperature-responsive antibacterial packaging and preservation film (PP / PC) with a CEO load according to the present invention.

[0027] Figure 2 The image shows the microstructure of the temperature-responsive antibacterial packaging and preservation film (PP / PC) with a CEO load according to the present invention. In the image, A is a scanning electron microscope (SEM) image of the PP / PC-0 nanofiber membrane and its fiber diameter distribution; B is a scanning electron microscope (SEM) image of the PP / PC-2 nanofiber membrane and its fiber diameter distribution; C is a scanning electron microscope (SEM) image of the PP / PC-4 nanofiber membrane and its fiber diameter distribution; D is a scanning electron microscope (SEM) image of the PP / PC-6 nanofiber membrane and its fiber diameter distribution; and E is a transmission electron microscope (TEM) image of the PP / PC nanofiber membrane.

[0028] Figure 3 This is a schematic diagram of the hydrophilicity and hydrophobicity of the temperature-responsive antibacterial packaging and preservation film (PP / PC) loaded with CEO of the present invention. A is a schematic diagram of the water contact angle of the PP / PC nanofiber membrane at 25℃ and 40℃; B is a schematic diagram of the water vapor permeability of the PP / PC nanofiber membrane at 25℃ and 40℃; C is a schematic diagram of the phase transition mechanism of the temperature-sensitive polymer PNVCL.

[0029] Figure 4 This is the infrared spectrum of the temperature-responsive antibacterial packaging and preservation film (PP / PC) with a CEO load of the present invention.

[0030] Figure 5 Thermogravimetric analysis diagram of the temperature-responsive antibacterial packaging and preservation film (PP / PC) with CEO load of the present invention.

[0031] Figure 6 This is a diagram showing the antibacterial diameter of the temperature-responsive antibacterial packaging and preservation film (PP / PC) loaded with CEO according to the present invention. A is the diameter of the inhibition zone of Escherichia coli and Staphylococcus aureus; B is the diameter of the colony against Aspergillus niger.

[0032] Figure 7 This is a schematic diagram illustrating the antioxidant activity of the temperature-responsive antimicrobial packaging and preservation film (PP / PC) loaded with CEO of the present invention at 25°C and 40°C.

[0033] Figure 8A schematic diagram showing the changes in appearance of bayberries with different packaging treatments after being stored at 25℃ and 70% relative humidity for 2 days and then at 35℃ and 70% relative humidity for 2 days. Detailed Implementation

[0034] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the specific embodiments described below are only for further illustration of the present application and are quite detailed, but should not be construed as limiting the scope of protection of this invention. Those skilled in the art can make various improvements and adjustments without departing from the concept of the present invention, and these improvements and adjustments all fall within the scope of protection of this invention.

[0035] Example 1

[0036] Combination Figure 1 As shown, the preparation method of the temperature-responsive antibacterial packaging and preservation film (PP / PC-4) loaded with cinnamon essential oil is as follows:

[0037] S1. Prepare PLA / CEO core spinning solution: Weigh 0.6g PLA and dissolve it in 5mL hexafluoroisopropanol. Stir with a magnetic stirrer until fully dissolved to obtain PLA solution (12% v / v). Take the prepared PLA solution and add 200μL of CEO (4% v / v). Mix thoroughly with a magnetic stirrer to obtain PLA / CEO spinning solution.

[0038] S2, Prepare PVA / PNVCL shell spinning solution: Weigh 0.1g PVA and 0.2g PNVCL (v:v=5:1), dissolve them together in 10mL of pure water, and stir with a magnetic stirrer to make them fully dissolved and uniform, so as to obtain PVA / PNVCL spinning solution.

[0039] S3, Preparation of temperature-responsive antibacterial packaging and preservation film (PP / PC-4) loaded with cinnamon essential oil: The prepared PLA / CEO core layer spinning solution was injected into a 5 mL syringe pump, and the PVA / PNVCL shell layer solution was injected into a 10 mL syringe pump for coaxial electrospinning. The feed rate of the propulsion pump was set to 0.3 mL·h. -1 0.6 mL·h -1 The distance between the needle tip and the flywheel collector (300 r / min) was 15 cm, and a voltage of 18 kV was applied, resulting in a polyvinyl alcohol / polyvinylacrylamide / polylactic acid / cinnamon oil-PP / PC (4%) nanocomposite film with a length and width of 27 cm × 17.5 cm. The microstructure and nanodiameter distribution of the prepared thermosensitive coaxial electrospun packaging film loaded with cinnamon oil are shown in the figure. Figure 2 As shown in C.

[0040] Comparative Example 1

[0041] A polylactic acid / polyvinyl alcohol / polyvinylcaprolactam packaging film (PP / PC-0) is prepared as follows: 0.6 g of PLA is dissolved in 5 mL of hexafluoroisopropanol and stirred at room temperature (200 r / min) for 6 hours (200 r / min) using a magnetic stirrer to ensure complete and uniform dissolution, yielding a core layer PLA solution (12% w / v). This solution is then allowed to stand overnight for degassing to obtain a core layer spinning solution. 0.1 g of PVA and 0.2 g of PNVCL (v:v = 5:1) are weighed and dissolved together in 10 mL of pure water. The solution is stirred with a magnetic stirrer to ensure complete and uniform dissolution, yielding a shell layer PVA / PNVCL spinning solution. The core layer spinning solution is injected into a 5 mL syringe pump, and the shell layer spinning solution is injected into a 10 mL syringe pump for coaxial electrospinning. The feed rate of the propulsion pump is set to 0.3 mL·h. -1 0.6 mL·h -1 An 18kV voltage was applied, and a non-woven fabric was used for receiving the sample. The distance between the needle tip and the flywheel collector (300r / min) was 15cm, resulting in a nano-packaging film with a length and width of 27cm × 17.5cm. The microstructure and nanometer diameter distribution of the prepared nano-packaging film are shown below. Figure 2 As shown in Figure A.

[0042] Comparative Example 2

[0043] A polylactic acid / polyvinyl alcohol / polyvinylcaprolactam / cinnamon essential oil packaging film (PP / PC-2) is prepared as follows: 0.6 g of PLA is dissolved in 5 mL of hexafluoroisopropanol and stirred at room temperature (200 r / min) with a magnetic stirrer for 6 hours to ensure complete and homogeneous dissolution, yielding a core layer PLA solution (12% w / v). 100 μL of CEO (2% v / v) is added to the prepared PLA solution and stirred with a magnetic stirrer to ensure complete mixing, yielding a PLA / CEO core layer spinning solution. 0.1 g of PVA and 0.2 g of PNVCL (v:v = 5:1) are weighed and dissolved together in 10 mL of pure water and stirred with a magnetic stirrer to ensure complete and homogeneous dissolution, yielding a shell layer PVA / PNVCL shell layer spinning solution. The core spinning solution was injected into a 5 mL syringe pump, and the shell spinning solution was injected into a 10 mL syringe pump for coaxial electrospinning. The feed rate of the propulsion pump was set to 0.3 mL / h. -1 0.6 mL·h -1 An 18kV voltage was applied, and a non-woven fabric was used for receiving the sample. The distance between the needle tip and the flywheel collector (300r / min) was 15cm, resulting in a nano-packaging film with a length and width of 27cm × 17.5cm. The microstructure and nanometer diameter distribution of the prepared nano-packaging film are shown below. Figure 2 As shown in B.

[0044] Comparative Example 3

[0045] A polylactic acid / polyvinyl alcohol / polyvinylcaprolactam / cinnamon essential oil packaging film (PP / PC-6) is prepared as follows: 0.6g of PLA is dissolved in 5mL of hexafluoroisopropanol and stirred at room temperature (200r / min) for 6 hours (200r / min) using a magnetic stirrer to obtain a core-layer PLA solution (12% w / v). 300μL of CEO (6% v / v) is added to the prepared PLA solution and stirred thoroughly using a magnetic stirrer to obtain a PLA / CEO core-layer spinning solution. 0.1g of PVA and 0.2g of PNVCL (v:v = 5:1) are dissolved together in 10mL of pure water and stirred thoroughly using a magnetic stirrer to obtain a shell-layer PVA / PNVCL shell-layer spinning solution. The core-layer spinning solution is injected into a 5mL syringe pump, and the shell-layer spinning solution is injected into a 10mL syringe pump for coaxial electrospinning. The feed rate of the push pump is set to 0.3mL·h. -1 0.6 mL·h -1 An 18kV voltage was applied, and a non-woven fabric was used for receiving the sample. The distance between the needle tip and the flywheel collector (300r / min) was 15cm, resulting in a nano-packaging film with a length and width of 27cm × 17.5cm. The microstructure and nanometer diameter distribution of the prepared nano-packaging film are shown below. Figure 2 As shown in D.

[0046] Performance tests were conducted on Example 1 and Comparative Examples 1-3, and the results are as follows:

[0047] I. Mechanical Properties

[0048] The mechanical properties of the packaging film were tested according to GB / T 10004-2008 standard, and the results are shown in Table 1. It can be seen that the temperature-responsive antibacterial packaging and preservation film (PP / PC-4) loaded with cinnamon essential oil obtained in Example 1 exhibits good mechanical properties, with tensile strength and maximum force reaching 5.26±0.72MPa and 3.08±0.31N, respectively.

[0049] Table 1 Mechanical properties of different packaging films

[0050]

[0051] II. Water Contact Angle (WCA) and Water Vapor Permeability (WVP)

[0052] The WCA of the fiber was accurately measured using a contact angle goniometer. 3.5 μL of distilled water was deposited on the film surface, and the contact angles on the left and right sides of the water droplet were subsequently measured at room temperature (25°C) and 40°C. WVP was measured using the ASTM E96 gravimetric method. Samples were weighed every 12 hours for 5 days. Figure 3 As shown, as the CEO content of the nanofiber membrane increased from 0% to 6%, the water contact angle also increased from 22.93±3.23°, 26.49±4.22°, 44.24±6.02°, 31.98±1.39° to 29.05±1.24°, 37.44±2.39°, 54.51±1.55° and 45.88±4.21°. Example PP / PC-4 had the highest WCA. As the temperature increased from 20°C to 40°C, the hydrophobicity of all fiber membranes increased, and the WCA also increased.

[0053] like Figure 3 As shown in Figure B, at room temperature, there was no significant difference in the WVP between Example PP / PC-4 and Comparative Examples 1-3 (PP / PC-0, 2, and 6). However, when the temperature exceeded the LCST of the temperature-sensitive material, reaching 40°C, the WVP of all fiber membranes increased. Example PP / PC-4 and Comparative Example 3 (PP / PC-6) exhibited extremely high WVPs, at 5.74 ± 0.37 g / (m³). 2 0.24h), 4.33±0.28g / (m 2 The increase in the content of CEO (hydrophobic material) (24h) is due to the increase in the content of CEO (hydrophobic material), which reduces the overall hydrophilicity of the film, destroys the polymer matrix, and thus promotes the transport of water vapor.

[0054] III. Fourier Transform Infrared Spectroscopy (FT-IR)

[0055] The intermolecular forces of the packaging film were analyzed using a vacuum Fourier transform infrared spectrometer (VERTEX 80V, Bruker GmbH, Germany), with a resolution of 4 cm⁻¹. -1 The frequency range is 4000-500cm. -1 .like Figure 4 As shown, Comparative Example 2PP / PC-2, Comparative Example 3PP / PC-6, and Example PP / PC-4 were compared at a wavelength of 2935 cm⁻¹. -1 The vibrations are attributed to the vibrations of CH; at 745 and 687 cm⁻¹ -1 The peaks represent the CH stretching vibrations of the benzene ring and olefin in cinnamaldehyde, respectively; at 1120 and 971 cm⁻¹. -1 The characteristic peak at 1440 cm⁻¹ was attributed to the COH stretching vibration of phenolic compounds in the CEO. Furthermore, the characteristic peaks of Examples 1 and Comparative Examples 2 and 3 increased from 1440 cm⁻¹. -1 Offset to 1450cm -1This indicates that CH stretching and hydrogen bonding interactions occurred between the CEO and PLA.

[0056] IV. Thermogravimetric Analysis (TGA)

[0057] The thermal stability of the nanofiber film was analyzed by thermogravimetric analysis. Figure 5 As shown, the weight loss of Examples 1-3 and Comparative Examples 1-3 is lower than that of PLA film. Figure 5 As shown in Figure B, the PLA nanofiber membrane exhibited the fastest degradation rate. The degradation rate of the nanofiber membranes decreased significantly after the addition of CEO and PNVCL, especially the nanofiber membrane in Example 1. This indicates that their addition improved the thermal stability of the PLA nanofiber membrane. The residual amount of the CEO-loaded nanofiber membrane was higher than that of the PLA nanofiber membrane, with Example 1 showing the highest residual amount and an initial decomposition temperature higher than other CEO-loaded nanofiber membranes, indicating that Example 1 had better thermal stability.

[0058] V. Antibacterial Properties

[0059] (1) The diameter of the inhibition zone was measured by the disc diffusion method to evaluate the effect of the nanofilm on the growth of Escherichia coli and Staphylococcus aureus after 24 hours. The diameter of the colony growth was measured by the fumigation method to evaluate the antibacterial effect of the nanofilm on Aspergillus niger at 40°C (above LCST). Figure 6 A shows that the inhibition zone of this material against Staphylococcus aureus is larger than that against Escherichia coli, and the maximum diameter of Staphylococcus aureus in the comparative example 3PP / PC-6 reached 23.68±0.22 mm. Figure 6 As shown in Figure B, Example PP / PC-4 and Comparative Example 3PP / PC-6 exhibited excellent antifungal activity, with inhibition diameters against Aspergillus niger of 18.92±0.58 mm and 14.20±0.30 mm, respectively. The use of CEO significantly improved the antimicrobial activity of the PP / PC-based films, particularly in inhibiting the growth of Aspergillus niger.

[0060] VI. Antioxidant properties

[0061] The antioxidant properties of the thin film were determined using the standard DPPH radical scavenging activity (RSA) method. Figure 7As shown, at 25℃, the RSA free radical scavenging activity continuously increased with increasing CEO content after 24 hours, with the highest RSA scavenging rate of Comparative Example 3PP / PC-6 reaching 82%, indicating that antioxidant activity is directly proportional to the increase of CEO concentration. When the temperature increased to 40℃, the RSA scavenging rates of all fiber membranes decreased by approximately 20%, 30%, 18%, and 60%, respectively, indicating that PNVCL inhibited the release of CEO, thereby reducing its antioxidant activity. The RSA scavenging rate of Example PP / PC-4 fiber membrane decreased less, indicating that its antioxidant activity was better than other fiber membranes.

[0062] VII. Preservation Performance Test of Waxberries

[0063] Figure 8 The diagram shows the changes in the appearance of bayberries under different treatments after storage at 25℃ and 80% relative humidity for 2 days, followed by storage at 40℃ and 80% relative humidity for 2 days. Table 2 shows the appearance quality indicators of bayberry fruits under different treatments after storage at 25℃ and 80% relative humidity for 2 days, followed by storage at 35℃ and 80% relative humidity for 2 days. Figure 8 As shown in Table 2, the coaxial electrospun temperature-sensitive packaging film loaded with CEO in the embodiments can effectively delay the quality deterioration of bayberries such as post-harvest rot, spoilage, and softening, and extend the post-harvest shelf life of bayberries.

[0064] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] The above embodiments illustrate and describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

[0066]

Claims

1. A method for preparing a temperature-responsive antibacterial packaging and preservation film, characterized in that: The packaging film core layer uses polylactic acid (PLA) as the film-forming substrate and cinnamon essential oil (CEO) as the antibacterial component; the shell layer uses polyvinyl alcohol (PVA) as the film-forming substrate and poly(N-vinylcaprolactam) (PNVCL) as the temperature sensor, and is prepared by electrospinning technology.

2. The formulation of the thermosensitive coaxial electrospun packaging film loaded with cinnamon essential oil according to claim 1, characterized in that: Using PLA and PVA as film-forming substrates, temperature-sensitive substance PNVCL and bio-antibacterial substance CEO are added.

3. The method for preparing a temperature-responsive antibacterial packaging and preservation film loaded with cinnamon essential oil according to claim 1, characterized in that... Prepared by coaxial electrospinning technology.

4. The method for preparing the temperature-responsive antibacterial packaging and preservation film loaded with cinnamon essential oil according to claim 3, characterized in that... Includes the following steps: (1) Preparation of polylactic acid / cinnamon oil (PLA / CEO) core spinning solution: Weigh PLA and dissolve it in hexafluoroisopropanol, stir it evenly to dissolve it completely, then add CEO (4% v / v) and mix it thoroughly to obtain PLA / CEO spinning solution. (2) Preparation of polyvinyl alcohol / polyvinylcaprolactam (PVA / PNVCL) shell spinning solution: Weigh PVA and PNVCL and dissolve them in pure water until they are evenly dissolved to obtain PVA / PNVCL spinning solution. (3) Preparation of nanofiber membrane: The core and shell spinning solutions are injected into an injection pump for coaxial electrospinning to obtain the temperature-responsive antibacterial packaging and preservation film loaded with cinnamon essential oil.

5. The application of the temperature-responsive antibacterial packaging and preservation film loaded with cinnamon essential oil according to claim 1, wherein the fruits and vegetables include bayberries, etc.

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