Trans-2-hexenal slow-release long-acting bacteriostatic packaging material as well as preparation method and application thereof

Abstract

The invention discloses a trans-2-hexenal slow-release long-acting bacteriostatic packaging material and a preparation method and application thereof.According to the preparation method, halloysite nanotubes are modified, trans-2-hexenal is loaded into the modified halloysite nanotubes, and the trans-2-hexenal slow-release long-acting bacteriostatic packaging material is obtained; and carrying out encapsulation treatment on the modified halloysite nanotube loaded with the trans-2-hexenal by adopting chitosan or a derivative thereof, so as to obtain the trans-2-hexenal slow-release long-acting antibacterial packaging material. According to the invention, the halloysite nanotube is used as a carrier to load the trans-2-hexenal, and the chitosan or the derivative thereof is used for encapsulation, so that the slow-release long-acting antibacterial effect of the trans-2-hexenal is realized. The packaging material can be widely applied to the field of food preservation, and the shelf life of food is effectively prolonged.

Description

Technical Field

[0001] This invention belongs to the technical field of food preservation packaging materials, specifically relating to a trans-2-hexenal slow-release long-acting antibacterial material, its preparation method, and its application. Background Technology

[0002] Trans-2-hexenal is a six-carbon aldehyde formed in plants from C18 and C16 unsaturated fatty acids (linolenic acid or linoleic acid) through the combined action of fatty acid oxidase (LOX) and hydroperoxide lyase (HPL). It has a green leafy or grassy aroma and is widely present in plants, being rapidly released when plants are subjected to stress such as mechanical damage or insect bites. Under appropriate storage conditions, such as protection from light, sealing, and low temperature, trans-2-hexenal can maintain its stability for a relatively long period and is not prone to decomposition or spoilage.

[0003] Chitosan and its derivatives are safe, non-toxic, biodegradable, and biocompatible natural polymers. Derived from chitin, the second most abundant polysaccharide in nature after cellulose, it is obtained through deacetylation. It has been approved as a recognized safe substance by the US Food and Drug Administration (FDA) and the European Union, among other regulatory agencies, and is widely used in the food industry, pharmaceuticals, and cosmetics. Chitosan and its derivatives possess broad-spectrum antibacterial activity, inhibiting various bacteria, fungi, and yeasts. Under acidic conditions, the amino groups on the chitosan molecular chain protonate into positively charged ammonium ions. The cell membranes of most microorganisms are negatively charged. The attraction between positive and negative charges leads to the adsorption of large amounts of chitosan onto the surface of microbial cells. This adsorption disrupts cell membrane integrity, increases membrane permeability, and causes leakage of essential intracellular components, resulting in cell lysis and death. Chitosan can effectively chelate metal ions, depriving microorganisms of essential trace elements for growth and inhibiting their enzyme activity and normal metabolism. Low molecular weight chitosan oligosaccharides may penetrate the cell wall, enter the cell interior, bind to DNA or RNA, and interfere with the replication and transcription of genetic material.

[0004] Therefore, using trans-2-hexenal and chitosan and its derivatives for food preservation is not only safe and non-toxic, but also highly effective in inhibiting and killing bacteria, making it a sustainable development option.

[0005] However, trans-2-hexenal has a small molecular weight, a low boiling point, and a high vapor pressure. At room temperature and pressure, trans-2-hexenal readily transforms from a liquid to a gaseous state, evaporating into the air. During storage and transportation, even when stored in sealed containers, small gaps or frequent opening and closing can cause trans-2-hexenal to leak out. To reduce volatilization, high-barrier packaging materials and complete sealing are required, which greatly limits its practical application. In the food processing industry, even a slight increase in temperature will cause most of the trans-2-hexenal to evaporate completely, leaving no trace in the product. Even if successfully added to a product, due to its volatility, it will evaporate entirely within a very short time after opening, failing to provide lasting flavor and antibacterial effects.

[0006] Therefore, how to develop a novel trans-2-hexenal sustained-release long-acting antibacterial material is an urgent problem that needs to be solved. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing trans-2-hexenal sustained-release long-acting antibacterial packaging material.

[0008] The present invention also aims to provide a trans-2-hexenal sustained-release long-acting antibacterial packaging material prepared by the above method.

[0009] The final objective of this invention is to provide the application of the above-mentioned trans-2-hexenal sustained-release long-acting antibacterial packaging material in the sustained-release inhibition of bacterial growth.

[0010] The first objective of this invention can be achieved by the following technical solution: a method for preparing a trans-2-hexenal sustained-release long-lasting preservation packaging material, comprising the following steps: (1) Modified halloysite nanotubes (HNT) are obtained by one or more of the following methods: ball milling, strong acid etching, calcium ion exchange and silane treatment. (2) Trans-2-hexenal was loaded into the modified halloysite nanotubes prepared in step (1) by vacuum loading or solvent-assisted loading to obtain modified halloysite nanotubes loaded with trans-2-hexenal. (3) The modified halloysite nanotubes loaded with trans-2-hexenal prepared in step (2) are encapsulated with chitosan or chitosan derivative solution and glutaraldehyde to obtain trans-2-hexenal sustained-release long-acting antibacterial packaging material.

[0011] In the preparation method of the above-mentioned trans-2-hexenal sustained-release long-acting antibacterial packaging material: Preferably, the halloysite nanotubes described in step (1) have a purity greater than 90%.

[0012] Preferably, the ball milling in step (1) is wet milling or dry milling.

[0013] Preferably, the strong acid used for etching in step (1) is a strong acid such as hydrochloric acid, sulfuric acid, nitric acid or hydrofluoric acid.

[0014] Preferably, the calcium salt used for calcium ion exchange in step (1) is calcium chloride or calcium nitrate.

[0015] The silane coupling agent used in step (1) is γ-aminopropyltriethoxysilane KH-550 or γ-glycidoxypropyltrimethoxysilane KH-560, etc.

[0016] Preferably, the ball milling speed in step (1) is 4000~6000 r / min, more preferably 5000 r / min, and the time is 30 min~2 h.

[0017] Preferably, the concentration of the strong acid used in step (1) is 1M to 5M, and the time is 3h to 8h.

[0018] Preferably, during the calcium ion exchange in step (1), the concentration of calcium ions is 0.01M~1.0M and the time is 2h~12h.

[0019] Preferably, the volume percentage of the silane coupling agent used in step (1) during the silane treatment is 2-3%, the reaction temperature during the silane treatment is 50-110℃, and the time is 2-24h.

[0020] Preferably, the mass ratio of trans-2-hexenal in step (2) to the modified halloysite nanotubes prepared in step (1) is 3:1 to 5:1.

[0021] Preferably, the pressure of the vacuum load in step (2) is -0.5MPa to -0.1MPa, and the processing time is 30min to 60min.

[0022] Preferably, the solvent used for solvent-assisted loading in step (2) is glyoxal or glutaraldehyde, and the processing time is 30 min to 90 min.

[0023] Preferably, the chitosan derivative in step (3) is a chitosan quaternary ammonium salt, carboxymethyl chitosan, chitosan oligosaccharide, or sulfonated chitosan.

[0024] Preferably, the degree of deacetylation of the chitosan or chitosan derivative in step (3) is greater than 55%.

[0025] Preferably, the chitosan or chitosan derivative in the chitosan or chitosan derivative solution in step (3) has a mass percentage content of 0.5% to 3%.

[0026] Preferably, the ratio of the amount of chitosan or chitosan derivative solution in step (3) to the amount of halloysite nanotubes modified with trans-2-hexenal prepared in step (2) is 1~3 mL: 1 g.

[0027] The second objective of the present invention can be achieved by the following technical solution: a trans-2-hexenal sustained-release long-acting antibacterial packaging material, prepared by the above method.

[0028] The last objective of the present invention can be achieved by the following technical solution: the application of the above-mentioned trans-2-hexenal sustained-release long-acting antibacterial packaging material in the sustained-release inhibition of bacterial growth.

[0029] Preferably, the bacteria are Staphylococcus aureus and / or Escherichia coli.

[0030] In some embodiments of the present invention, the present invention also provides the application of the above-described trans-2-hexenal sustained-release long-acting antibacterial packaging material in the sustained-release inhibition of the growth of Staphylococcus aureus and / or Escherichia coli.

[0031] Compared with the prior art, the present invention has the following advantages: (1) The trans-2-hexenal sustained-release long-acting antibacterial packaging material of the present invention improves the specific surface area and loading rate by modifying halloysite nanotubes, and achieves sustained release by electrostatic encapsulation of chitosan or chitosan derivatives, thereby extending the antibacterial effect of the natural antibacterial agent trans-2-hexenal by more than 1 time (the unencapsulated material becomes ineffective after 5 days, while the encapsulated material maintains strong antibacterial effect for 10 days and becomes completely ineffective after 12 days). (2) The preparation method of trans-2-hexenal sustained-release long-acting antibacterial packaging material in this invention is simple, easy to operate, and easy to implement; (3) The trans-2-hexenal slow-release long-acting antibacterial packaging material of the present invention is non-toxic and safe for food contact, and can significantly improve the long-acting antibacterial performance against Staphylococcus aureus and Escherichia coli. Attached Figure Description

[0032] Figure 1 The nitrogen adsorption-desorption curves of AHNT and AHNT / Hexenal in Example 1 of this invention are shown. The horizontal axis represents relative pressure, and the vertical axis represents the absorption volume. Figure 2 The figure shows the pore size distribution of AHNT and AHNT / Hexenal in Example 1 of this invention. The horizontal axis represents pore width, and the vertical axis represents d. V / d(lg D () represents the unit logarithmic particle size volume distribution; Figure 3These are scanning electron microscope (SEM) images of chitosan-encapsulated HNT-3M nanotubes before and after acid etching in Example 1 of the present invention, where (a) is the morphology image of HNT-3M before CTS encapsulation and (b) is the morphology image of HNT-3M after CTS encapsulation. Figure 4 The infrared spectra of chitosan-encapsulated halloysite nanotubes before and after acid etching in Example 1 of this invention are shown. Figure 5 The images show the antibacterial effect of halloysite nanotubes loaded with trans-2-hexenal in Example 4 of this invention; the four images on the left show Staphylococcus aureus, and the four images on the right show Escherichia coli. Figure 6 The above images show the sustained-release effect of halloysite nanotubes loaded with trans-2-hexenal in Example 5 of this invention. The top three images show Staphylococcus aureus, and the bottom three images show Escherichia coli. Figure 7 The images show the antibacterial and sustained-release effects of chitosan-encapsulated halloysite nanotubes loaded with hexenal in Example 5 of this invention. The four images on the left show Staphylococcus aureus, and the four images on the right show Escherichia coli. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0034] Unless otherwise specified, all reagents and materials used in the following examples are commercially available products. Example 1

[0035] The preparation method of the trans-2-hexenal sustained-release long-acting antibacterial packaging material provided in this embodiment includes the following steps: (1) Weigh 5g of halloysite nanotubes (HNT, purity greater than 90%) and put them into a three-necked flask. Add 120 mL of 1M sulfuric acid solution and react for 7h. After the reaction is completed, centrifuge at 8000r / min for 3min to separate the solid part. Dry it and grind it into powder. Disperse the acid-etched halloysite nanotube powder in 0.5M CaCl2 solution. Place the mixed suspension on a magnetic stirrer and stir vigorously at room temperature for 5 hours. After the reaction is completed, use a high-speed centrifuge to separate the solid product. Place the washed filter cake in an oven at 60~80℃ and dry it overnight. Grind it into powder the next day to obtain the target intermediate product modified halloysite nanotubes (AHNT). (2) The solid from the previous step was mixed with trans-2-hexenal (Hexenal) at a mass ratio of 1:3. The mixture was stirred with a glass rod for 30 min. The suspension was transferred to a vacuum dryer. After the vacuum reached -0.1 MPa, the suspension was kept in this state for 40 min. The suspension was centrifuged at 8000 r / min for 3 min to separate the solid phase from the suspension and obtain modified halloysite nanotubes loaded with trans-2-hexenal. (3) Weigh 5g of the above solid-loaded trans-2-hexenal modified halloysite nanotubes, add 10 mL of chitosan (deacetylation degree greater than 55%) with a concentration of 1.5wt% and 0.5 mL of glutaraldehyde, and stir continuously for 5 min. Transfer the above mixture to a centrifuge tube, set the centrifuge speed to 5000 r / min, centrifuge for 3 min, and place the precipitate obtained after centrifugation in a fume hood to dry for 12 h to obtain the target product trans-2-hexenal sustained-release long-acting antibacterial packaging material.

[0036] The nitrogen adsorption / desorption curves of the modified halloysite nanotubes (AHNT / Hexenal) supported on trans-2-hexenal prepared in step (2) and the modified halloysite nanotubes (AHNT) prepared in step (1) are shown below. Figure 1 As shown.

[0037] Figure 1 The nitrogen adsorption / desorption curves showed that the AHNT (halothallium nanotubes) / Hexenal supported on trans-2-hexenal exhibited a significant decrease in adsorption capacity compared to the unsupported sample (AHNT). Figure 2 The pore size distribution shows that the intensity of the pore size distribution in the 3-30 nm range is significantly reduced; Specifically, the specific surface area decreased from 108 m² / g (AHNT) to 25.3 m² / g (AHNT / Hexenal); the pore volume decreased from 0.552 cm³ / g (AHNT) to 0.241 cm³ / g (AHNT / Hexenal); and the intensity of the 3-30 nm pore size distribution was significantly reduced.

[0038] The above changes confirm that the trans-2-hexenal molecule selectively occupies the cavity space of halloysite nanotubes, resulting in a reduction in the effective volume of the pores. This phenomenon directly verifies the successful loading of the target molecule into the cavity.

[0039] Table 1 Surface area and pore volume of AHNT / Hexenal and AHNT sample <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Pore volume (cm 3 / g)]]> AHNT 108 0.552 AHNT / Hexenal 25.3 0.241 The scanning electron microscope (SEM) images of the chitosan-encapsulated halloysite nanotubes before and after acid etching in this embodiment are as follows: Figure 3 As shown.

[0040] Figure 3 (a) shows that the AHNT surface is smooth and of uniform length. Figure 3 In (b), the surface of the chitosan-coated sample exhibits significant roughening. This phenomenon is due to the protonation of chitosan amino groups at a specific pH: positively charged chitosan molecules bind to the surface of negatively charged halloysite nanotubes through electrostatic adsorption, enhancing the electrostatic repulsion between nanotubes and leading to structural rearrangement, thus forming a rough surface morphology. This result indicates that effective coating of chitosan on the surface of halloysite nanotubes can be achieved based on the electrical difference controlled by pH (chitosan is slightly soluble in water, and acid needs to be added to adjust the pH when preparing a solution).

[0041] The infrared spectra of chitosan-encapsulated halloysite nanotubes before and after acid etching in this embodiment are as follows: Figure 4 As shown.

[0042] Comparative analysis Figure 4 Infrared spectrum: AHNT / Hexenal characteristic peaks: 3682 / 3609 cm⁻¹ -1 (Surface hydroxyl stretching vibration), 10¹¹ cm -1 (Intra-Si-O bond vibration); CTS characteristic peak: 3452 cm⁻¹ -1 (NH stretching vibration), 2885 cm -1 (CH stretching vibration), 1611 cm -1 (Amide I band); AHNT / Hexenal@CTS new peak: 1623 cm⁻¹ (amide I band) → compared with CTS 1611 cm⁻¹ -1 Consistent; 2890cm -1 (CH stretching vibration) → 2885 cm with CTS -1 Correspondingly, the appearance of the above CTS characteristic peaks directly confirms the formation of halloysite nanotube-chitosan composite structure in the sample. Example 2

[0043] The preparation method of the trans-2-hexenal sustained-release long-acting antibacterial packaging material provided in this embodiment includes the following steps: (1) Add anhydrous ethanol and deionized water to a beaker in proportion, adjust the pH of the mixed solution to 4-5 with glacial acetic acid, slowly add a measured amount of KH-550 while stirring continuously, the volume percentage of silane coupling agent is 2.5%, continue stirring for 30 minutes to 1 hour to allow it to be fully hydrolyzed; weigh 10g halloysite nanotubes (HNT), add them to the above hydrolysate, transfer the mixed system to a three-necked flask equipped with a condenser, place it in a constant temperature water bath at 70-80°C, reflux for 4-6 hours while stirring continuously and vigorously, after the reaction is completed, cool to room temperature; wash by centrifugation or filtration multiple times with ethanol / water mixed solution or anhydrous ethanol until no white precipitate is detected in the supernatant by silver nitrate solution, place the washed filter cake in an oven at 80°C and dry for 12 hours, gently grind the dried block product in an agate mortar, and sieve to obtain modified halloysite nanotubes; (2) The solid from the previous step was mixed with trans-2-hexenal at a mass ratio of 1:5. The mixture was stirred with a glass rod for 30 min. The suspension was transferred to a vacuum dryer. After the vacuum reached -0.1 MPa, the suspension was kept in this state for 40 min. The suspension was centrifuged at 8000 r / min for 3 min to separate the solid phase from the suspension. The dried block product was gently ground in an agate mortar and sieved to obtain modified halloysite nanotubes loaded with trans-2-hexenal. (3) Weigh 10g of the above solid, add 10mL of 1.5% carboxymethyl chitosan solution and 0.5mL of glutaraldehyde, and stir continuously for 10min. Transfer the above mixture to a centrifuge tube, set the centrifuge speed to 5000r / min, centrifuge for 3min, place the precipitate obtained after centrifugation in a fume hood and dry for 12h. Gently grind the dried block product in an agate mortar and sieve to obtain the target product trans-2-hexenal sustained-release long-acting antibacterial packaging material. Example 3

[0044] The preparation method of the trans-2-hexenal sustained-release long-acting antibacterial packaging material provided in this embodiment includes the following steps: (1) Weigh 5g halloysite nanotubes (HNT) and put them into a three-necked flask. Add an appropriate volume of 0.01M calcium chloride solution and then place them in a constant temperature water bath at 60℃ for 2 hours. After the reaction is complete, cool the suspension to room temperature and use a vacuum filtration device to separate the solid and liquid. Carefully scrape the washed filter cake off the filter paper and place it in a petri dish or petri dish. Spread it into a thin layer and dry it in an oven at 60℃ for 24 hours. Gently grind the dried block product in an agate mortar and sieve it to obtain uniform modified powder modified halloysite nanotubes. (2) Mix the solid from the previous step with trans-2-hexenal at a mass ratio of 1:5, stir with a glass rod for 30 min, add an appropriate amount of glutaraldehyde solution to the suspension, stir continuously for 40 min, centrifuge the suspension at a speed of 8000 r / min for 3 min, separate the solid phase in the suspension, gently grind the dried block product in an agate mortar, and sieve to obtain modified halloysite nanotubes loaded with trans-2-hexenal; (3) Weigh 5g of the above solid, add 10mL of 1.5% chitosan solution and 0.5mL of glutaraldehyde, and stir continuously for 15min. Transfer the mixture to a centrifuge tube, set the centrifuge speed to 5000r / min, centrifuge for 3min, place the precipitate obtained after centrifugation in a fume hood and dry for 12h. Gently grind the dried block product in an agate mortar and sieve to obtain the target product trans-2-hexenal sustained-release long-acting antibacterial packaging material.

[0045] Example 3 Antibacterial test of trans-2-hexenal powder Prepare the culture medium according to the culture medium formula (the preparation method of LB liquid medium: dissolve 10g of tryptone, 5g of yeast extract and 10g of sodium chloride in 1L of distilled water, then adjust the pH to about 7.0 and incubate at a constant temperature of 37℃ for 48h). Sterilize at 121℃ for 20min. Activate Escherichia coli and Staphylococcus aureus on the corresponding culture medium. Use a specific punch with a diameter of 0.8cm to punch holes on the surface of the solidified culture medium. Weigh 0.1g of the first-loaded trans-2-hexenal powder (without chitosan encapsulation), 0.1g of the second-loaded sample (repeated from the first-loaded step), and 0.1g of the third-loaded sample (repeated from the second-loaded step) prepared in Example 1, and slowly and evenly inject them into the previously drilled holes. At the same time, use the modified halloysite nanotubes (prepared in step (1) of Example 1) as a blank group, and perform pre-diffusion at 4°C for 1h. Place the plate in a 37°C constant temperature bacterial incubator and incubate for 24h. After cultivation, the diameter of the inhibition zone on the plate was measured using the cross-cross method. This method involves running a ruler across the center of the colony growth to measure two perpendicular diameters, and then calculating their average value to obtain the average diameter of the inhibition zone.

[0046] The antibacterial effect of halloysite nanotubes loaded with trans-2-hexenal is shown in the figure below. Figure 5 As shown.

[0047] Figure 5 The antibacterial experimental data show that: Unloaded sample (modified halloysite nanotubes prepared in step (1) of Example 1): The diameter of the inhibition zone against Staphylococcus aureus / Escherichia coli was 0 mm (insensitive); Sample loading in one run: Staphylococcus aureus: 12 mm (intermediate sensitivity), Escherichia coli: 13 mm (intermediate sensitivity); Two loading samples: Staphylococcus aureus: 21 mm (extremely sensitive), Escherichia coli: 20 mm (extremely sensitive); Three loading samples: Staphylococcus aureus: 32 mm (extremely sensitive), Escherichia coli: 29 mm (extremely sensitive); from Figure 5 It can be seen that the diameter of the inhibition zone increases significantly with the increase of loading times, proving that the loading amount of trans-2-hexenal is positively correlated with the antibacterial strength, and the sample with 3 loading times performed the best.

[0048] Example 5: Sustained-release assay of halloysite nanotubes supporting trans-2-hexenal Halloysite nanotubes loaded with trans-2-hexenal (see Example 4, without chitosan encapsulation) were selected as the antibacterial material. Before conducting the antibacterial experiment, the material was placed in a constant temperature drying oven at 25°C. After three days, it was removed and used as the antibacterial material to verify the antibacterial efficacy of the halloysite nanotubes loaded with trans-2-hexenal. The effective antibacterial period of the halloysite nanotubes loaded with trans-2-hexenal was determined by the following experiment. Figure 6 (5 days) Chitosan-encapsulated halloysite nanotubes loaded with trans-2-hexenal were placed in a 25°C constant temperature drying oven for more than the effective antibacterial period of the halloysite nanotubes loaded with trans-2-hexenal before being taken out for antibacterial experiments.

[0049] The sustained-release effect of halloysite nanotubes supporting trans-2-hexenal is as follows: Figure 6 As shown.

[0050] Antibacterial test data ( Figure 6 According to the relevant standards of the National Clinical Laboratory Standards Committee (NCCIS) (inhibition zone diameter >20mm is extremely sensitive; 10mm-20mm is moderately sensitive; 5mm-10mm is lowly sensitive; ≤5mm is insensitive), the antibacterial efficacy of three loaded samples (HNT / Hexenal) after storage at 25℃ was tested as follows: 1 day of storage: Staphylococcus aureus: 29mm (extremely sensitive), Escherichia coli: 30mm (extremely sensitive); 3 days of storage: Staphylococcus aureus: 19mm (moderately sensitive), Escherichia coli: 18mm (moderately sensitive); 5 days of storage: inhibition zone diameter was 0mm (insensitive). The data show that the antibacterial efficacy of the samples decreased in a stepwise manner with prolonged storage time, and was completely ineffective after 5 days.

[0051] The sustained-release effect of chitosan-encapsulated halloysite nanotubes supporting trans-2-hexenal is as follows: Figure 7 As shown.

[0052] The antibacterial efficacy of chitosan-coated samples (HNT / Hexenal@CTS) was tested after being stored at a constant temperature of 25℃. Figure 7 ): After 5 days of storage: Staphylococcus aureus: 29 mm (extremely sensitive), Escherichia coli: 27 mm (extremely sensitive); After 8 days of storage: Staphylococcus aureus: 25 mm (extremely sensitive), Escherichia coli: 22 mm (extremely sensitive); After 10 days of storage: Staphylococcus aureus: 17 mm (moderately sensitive), Escherichia coli: 17 mm (moderately sensitive); After 12 days of storage: The diameter of the inhibition zone was 0 mm (insensitive); Compared with the uncoated sample (AHNT / Hexenal), which completely failed after 5 days, the coated sample maintained extremely sensitive antibacterial efficacy for 8 days, extending the shelf life by ≥100%. This result confirms that chitosan coating achieves long-term sustained release of trans-2-hexenal.

[0053] The above examples illustrate specific embodiments of the present invention. It is important to note that these specific embodiments are only for further explanation and do not constitute a limitation on the scope of protection of the present invention. Non-essential modifications and adjustments made by others based on the present invention still fall within the scope of protection of the present invention.

Claims

1. A method for preparing a trans-2-hexenal slow-releasing long-lasting bacteriostatic packaging material, characterized by, It comprises the following steps: (1) modifying halloysite nanotubes by one or more of ball milling, strong acid etching, calcium ion exchange and silane treatment to obtain modified halloysite nanotubes; (2) loading trans-2-hexenal into the modified halloysite nanotubes prepared in step (1) by vacuum loading or solvent-assisted loading to obtain trans-2-hexenal-loaded modified halloysite nanotubes; (3) encapsulating the trans-2-hexenal-loaded modified halloysite nanotubes prepared in step (2) with chitosan or chitosan derivatives and glutaraldehyde to obtain a trans-2-hexenal slow-release long-acting antibacterial packaging material.

2. The preparation method of the trans-2-hexenal sustained-release long-acting antibacterial packaging material according to claim 1, characterized in that, The purity of the halloysite nanotubes in step (1) is greater than 90%; the ball milling in step (1) is wet milling or dry milling; the strong acid for strong acid etching in step (1) is hydrochloric acid, sulfuric acid, nitric acid or hydrofluoric acid; the calcium salt used for calcium ion exchange in step (1) is calcium dichloride or calcium nitrate; and the silane coupling agent used for silane treatment in step (1) is γ-aminopropyl triethoxysilane KH-550 or γ-glycidyl ether propyl trimethoxysilane KH-560.

3. The method of claim 2, wherein the trans-2-hexenal slow-release long-lasting antimicrobial packaging material is prepared by the steps of: (a) preparing a solution of trans-2-hexenal; (b) adding the solution of trans-2-hexenal to a porous material; and (c) drying the porous material. The rotation speed of the ball milling in step (1) is 4000-6000 r / min, and the time is 30 min-2 h; the concentration of the strong acid for strong acid etching in step (1) is 1M-5M, and the time is 3h-8h; the concentration of calcium ions when the calcium ion exchange in step (1) is 0.01M-1.0M, and the time is 2h-12h; the volume percentage content of the silane coupling agent used for silane treatment in step (1) is 2-3%, the reaction temperature for silane treatment is 50-110℃, and the time is 2h-24h.

4. The preparation method of the trans-2-hexenal sustained-release long-acting antibacterial packaging material according to claim 1, characterized in that, The mass ratio of trans-2-hexenal to the modified halloysite nanotubes prepared in step (1) in step (2) is 3:1-5:

1.

5. The method for preparing the trans-2-hexenal sustained-release long-acting antibacterial packaging material according to claim 1, characterized in that, The pressure for vacuum loading in step (2) is-0.5MPa--0.1MPa, and the treatment time is 30min-60min; the solvent for solvent-assisted loading in step (2) is glycolaldehyde or glutaraldehyde, and the treatment time is 30min-90min.

6. The method for preparing the trans-2-hexenal sustained-release long-acting antibacterial packaging material according to claim 1, characterized in that, The chitosan derivative in step (3) is chitosan quaternary ammonium salt, carboxymethyl chitosan, chitooligosaccharide or sulfonated chitosan; and the degree of deacetylation of the chitosan or chitosan derivative in step (3) is greater than 55%.

7. The method for preparing the trans-2-hexenal sustained-release long-acting antibacterial packaging material according to claim 1, characterized in that, The mass percentage content of the chitosan or chitosan derivative in the chitosan or chitosan derivative solution in step (3) is 0.5%-3%; and the amount ratio of the chitosan or chitosan derivative solution to the trans-2-hexenal-loaded modified halloysite nanotubes prepared in step (2) in step (3) is 5-15mL:5g.

8. A trans-2-hexenal slow-release long-lasting bacteriostatic packaging material, characterized by, The trans-2-hexenal slow-release long-acting antibacterial packaging material is prepared by the method of any one of claims 1-7.

9. The trans-2-hexenal slow-release long-acting antibacterial packaging material of any one of claims 1-7 for use in slow-release inhibition of bacterial growth.

10. Use according to claim 8, characterized in that, The bacteria are Staphylococcus aureus and / or Escherichia coli.

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