A composite film for mycotoxin degradation and antibiosis and a preparation method thereof

Abstract

This invention belongs to the field of nanomaterials and food packaging, specifically relating to a nanocomposite packaging film with dual functions of degrading toxins and antibacterial properties, and its preparation method. This invention provides a dual-functional composite film for degrading and inhibiting the growth of mycotoxins (aflatoxin B1), and its preparation method. Prussian blue nanoparticles are loaded onto a chitosan-gelatin composite film to prepare a nanomaterial-based dual-functional composite film that not only degrades mycotoxins and kills bacteria, but also allows for timely recycling, further protecting the nutritional components of food.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials and food packaging, specifically relating to a nanocomposite packaging film with dual functions of degrading toxins and antibacterial properties, and its preparation method. Background Technology

[0002] Mycotoxins are toxic metabolites produced by molds in contaminated food, posing a serious threat to human and animal health. Fungal growth and mycotoxin production can occur in the field or during storage under suitable temperature and humidity conditions. These toxins can enter the bodies of humans and animals through feed or food, causing acute or chronic poisoning and damaging the liver, kidneys, nervous tissue, hematopoietic tissue, and skin. Furthermore, mycotoxins cause significant economic losses annually, including loss of human and animal lives, livestock productivity losses, and losses of forage crops. Many traditional physical and chemical strategies for eliminating or inactivating mycotoxins have been reported in the literature. However, these methods have limitations in terms of safety, loss of nutritional value, and feed palatability, coupled with limited effectiveness and cost. Therefore, it is urgent to find an effective, specific, feasible, and environmentally friendly removal technology.

[0003] In addition, during the storage, transportation and preservation of food, changes in conditions can easily lead to bacterial growth, and food safety issues caused by foodborne pathogens are receiving increasing attention worldwide. Song Aiqing, Ren Liping, Zhang Geng. Preparation of gelatin composite film and its application in food preservation [J]. Food Industry, 2015, 36(3):4. DOI:CNKI:SUN:SPGY.0.2015-03-035. It was disclosed that when the amount of gelatin added was 70%, the amount of chitosan added was 35%, and the amount of glycerol added was 2%, the gelatin composite film had the best performance. Application tests proved that it played a good role in the preservation of strawberries and fresh meat. Zhang Liting, Jiang Ziwen, Gao Lei, et al. Preparation and antibacterial properties of edible chitosan-gelatin composite film [J]. Food Research and Development, 2020, 41(6):7. DOI:CNKI:SUN:SPYK.0.2020-06-022. Using chitosan and gelatin as the composite film skeleton material, an edible composite film with significant antibacterial properties was prepared by adding 0.3% (volume ratio) glycerol plasticizer. A series of sterilization methods, such as heat sterilization, high-pressure steam sterilization, chemical preservative sterilization and radiation sterilization, are widely used. However, high temperature will bring about changes in the physical and chemical properties of food and adverse effects on flavor and nutritional components, and sterilization by-products will bring carcinogenic risks. Therefore, it is urgent to develop green and reliable methods to kill bacteria in food.

[0004] Prussian blue nanoparticles (PB) have become a research hotspot in recent years due to their excellent near-infrared (NIR)-driven photothermal conversion properties (photothermal effect), peroxidase properties, and good optical properties. Their low preparation cost, ease of synthesis, good stability, and biocompatibility have led to their rapid development in the fields of biosensing and photothermal therapy. Even more exciting is their potential for excellent degradation of fungal toxins and bactericidal activity under near-infrared light irradiation. The principle of PB's toxin degradation relies on its role as a photo-Fenton reagent in catalytically degrading mycotoxins under near-infrared light conditions. Although research on PB as a photothermal bactericide has yielded some results, many problems remain, the most important being biosafety. PB recycling is relatively troublesome, requiring complex methods such as membrane filtration; failure to recycle in a timely manner can lead to residues in food, thus posing a health risk. Conversely, timely recycling can not only avoid residues but also prevent resource waste. Therefore, in order to achieve the recyclability of PB photothermal materials, if PB can be fixed into a composite containing chitosan and gelatin to prepare a composite smart membrane, it can not only achieve the functions of degrading fungal toxins and killing bacteria, but also be recycled in time, further protecting the nutritional components of food. Summary of the Invention

[0005] To obtain a composite membrane capable of degrading fungal toxins and killing foodborne pathogens, the present invention provides the following technical solution:

[0006] On one hand, this invention provides a method for preparing a composite membrane for degrading aflatoxin. Prussian blue nanoparticles (PB) are introduced into a chitosan-gelatin matrix membrane to prepare a nanomaterial composite membrane, which further significantly improves the photothermal, electrical, chemical, and other properties of the synthesized composite membrane. The preparation method is as follows:

[0007] Potassium ferrocyanide was weighed and completely dissolved in hydrochloric acid solution. The supernatant was removed by centrifugation and the solution was dried under vacuum to obtain PB. Subsequently, chitosan (CS) was dissolved in glacial acetic acid and stirred until homogeneous, which was denoted as solution A. Gelatin (Gel) was added to the aqueous solution and stirred until homogeneous, which was denoted as solution B. Solutions A and B were mixed and stirred until homogeneous. PB and glycerol were added to the mixture and stirred until homogeneous. Solution C was obtained after PB was completely dissolved. Solution C was poured into a membrane container and dried in a drying oven. After complete drying, the composite membrane was peeled off to obtain a composite membrane with fungal toxin degradation function.

[0008] On the other hand, the present invention provides a composite membrane with antibacterial function, which is prepared by the above-described preparation method.

[0009] The beneficial effects of this invention are:

[0010] Experiments have shown that the composite membrane prepared by the method of the present invention exhibits excellent degradation performance against aflatoxin B1, and also has a certain inhibitory and bactericidal effect on foodborne pathogens. Attached Figure Description

[0011] Figure 1 This is a circuit diagram for the preparation of the bifunctional composite membrane of the present invention.

[0012] Figure 2 A comparison of the removal rates of AFB1 by chitosan (CS) membrane, gelatin (Gel) membrane, chitosan-gelatin (CS+Gel) composite membrane, and chitosan-gelatin-Prussian blue (CS+Gel+PB) membrane.

[0013] Figure 3 The test results for the photothermal properties of the composite film of this application are as follows: Figure 3 (a) Photothermal properties of films with different PB contents (PB1: 0.1 mg / mL, PB2: 0.2 mg / mL, PB3: 0.3 mg / mL, PB4: 0.5 mg / mL) in aqueous solution under 808 nm laser irradiation; Figure 3 (b) Composite film under 808nm laser irradiation (C PB Five repeated photothermal cycles of (0.5 mg / mL) were obtained.

[0014] Figure 4 The composite membrane prepared in this invention exhibits inhibitory and bactericidal effects against Escherichia coli. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0016] Example 1

[0017] The preparation method of the composite membrane for degrading aflatoxin according to Example 1 of the present invention will be described with reference to the accompanying drawings. Figure 1 As shown, this preparation method loads Prussian blue nanoparticles (PB) onto a chitosan-gelatin composite membrane matrix to obtain a composite membrane for degrading aflatoxin. The preparation method is as follows:

[0018] Weigh 0.0422 g of potassium ferrocyanide, add 10 mL of hydrochloric acid (0.25 M), react at 60 °C for 6 h, centrifuge to remove the supernatant, and vacuum dry (60 °C) overnight. Add 0.18 g of chitosan (CS) to 12 mL of glacial acetic acid aqueous solution (1%), stir evenly at 40 °C, and label this solution A. Add 0.1 g of gelatin (Gel) to 8 mL of aqueous solution, stir evenly at 40 °C, and label this solution B. Mix solutions A and B evenly, add 4 mg of PB to make the PB concentration in the entire liquid 0.2 mg / mL, add 0.06 mL of glycerol, stir evenly, and wait for PB to completely dissolve to obtain solution C. Degas the solution by sonication, let it stand for a period of time until the bubbles completely disappear. Pour solution C into a mold and dry it overnight in a drying oven at 40 °C to obtain a composite membrane, which is used for photocatalytic degradation of aflatoxin.

[0019] To verify the degradation performance of the composite membrane obtained by the above preparation method, 30 small circular pieces (8 mm in diameter) were cut from the composite membrane using a perforator and dispersed in 3 mL of AFB1 solution with a concentration of 1 μg / mL. The mixture was allowed to react in the dark for 30 min to reach adsorption-desorption equilibrium. Then, photocatalytic degradation experiments were conducted using 808 nm near-infrared light. Figure 2 As shown, the composite membrane has an absorption rate of 30.037% for AFB1. After adding H2O2 and irradiating with near-infrared light for 4 hours, the composite membrane achieves a removal rate of 100% for AFB1.

[0020] The photothermal properties of the composite film were studied, and five cycles of experiments were conducted to further demonstrate its photothermal stability. Figure 3 As shown in Figure a, the temperature of the composite film tends to stabilize after 8 minutes of near-infrared light irradiation, and the photothermal performance of the composite film improves with increasing PB concentration. Figure 3 As shown in b, after five repeated cycles of the experiment, the temperature of the composite film decreased by only 2.14% after illumination, which confirms that the composite film has good and stable photothermal properties.

[0021] Example 2

[0022] Same reference Figure 1 Prussian blue nanoparticles (PB) were loaded onto a chitosan-gelatin composite membrane matrix to obtain a composite membrane for antibacterial purposes.

[0023] Except for the addition of nanomaterials (10 mg of PB), the procedure was the same as in Example 1. Figure 4 The study described different treatments: chitosan (CS) membrane, gelatin (Gel) membrane, chitosan-gelatin (CS+Gel) composite membrane, and chitosan-gelatin-Prussian blue (CS+Gel+PB) membrane, along with PB, NIR, PB+NIR, CS+Gel+PB+NIR, and a control group. The antibacterial properties of the composite membranes were verified, and the results are as follows: Figure 4The diagram shows that five small circular pieces with a diameter of 8 mm were cut from the (CS+Gel+PB) membrane and mixed with diluted E. coli solution (10). 5 The sample (CFU / mL) was incubated in a biochemical incubator at a constant temperature (37℃) for 1 hour, and then subjected to near-infrared laser treatment (808nm, 4.0W / cm²). 2 After irradiating for 10 minutes, 100 μL of the mixed bacterial solution was diluted and inoculated onto a solid culture medium. The culture dish was placed in a constant temperature (37℃) biochemical incubator for 24 hours, and the bacterial growth was observed. The near-infrared light combined with the membrane and irradiated for 10 minutes showed a 100% killing effect on the foodborne bacteria Escherichia coli, which confirms that the composite membrane has excellent antibacterial activity.

Claims

1. A composite membrane for fungal toxin degradation and antibacterial purposes, characterized in that, The composite membrane comprises the following components: chitosan, gelatin, plasticizer glycerol, and Prussian blue nanoparticles; the composite membrane is prepared by completely dissolving potassium ferrocyanide in hydrochloric acid solution, centrifuging to remove the supernatant, and vacuum drying to obtain Prussian blue nanoparticles. Chitosan was dissolved in glacial acetic acid and stirred until homogeneous, denoted as solution A. Gelatin was added to an aqueous solution and stirred until homogeneous, denoted as solution B. Solution A and solution B were mixed and stirred until homogeneous. Prussian blue nanoparticles and glycerol were added to the mixture and stirred until homogeneous. Once the nanoparticles were completely dissolved, solution C was obtained. Solution C was poured into a membrane container and dried in a drying oven. Once completely dried, a composite membrane with fungal toxin degradation and antibacterial properties was obtained.

2. The application of the composite membrane according to claim 1 in the degradation of fungal toxins.

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