A method for preparing antibacterial and antiviral packaging material and packaging material using the same

Abstract

The present invention relates to a method for preparing an antibacterial and antiviral packaging material, comprising the following steps: S1: extracting ryegrass leaves with a solvent to obtain ryegrass extract; S2: dissolving the obtained ryegrass extract with a solvent, and mixing it with modified mesoporous silica to obtain a nano drug-carrying material; S3: mixing the obtained nano drug-carrying material with modified polylactic acid, and then mixing it with an organic solvent to prepare a spinning solution, and spinning into a film through an electrostatic spinning process to obtain the antibacterial and antiviral packaging material.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional packaging materials, and in particular, relates to a method for preparing an antibacterial and antiviral packaging material and a packaging material using the same. Background Art

[0002] In the traditional field of food preservation, chemical preservative materials need to be added to food to prevent food from being contaminated by microorganisms or other substances during production, transportation, storage, and sales. Generally speaking, traditional antimicrobial agents used in food will affect the flavor of food, have high toxicity, threaten human health, and have poor antibacterial effects. For example, preservatives such as sorbate, benzoate, nitrite, and hydrogen peroxide are directly mixed into food formulas, which will change the original flavor of the food; antibacterial cardboard or antibacterial pouches containing metal ions such as silver, copper, and zinc are directly placed in the packaging, which has low antibacterial efficiency. With the development of new food packaging materials and people's attention to their own health, antibacterial packaging has emerged in order to ensure food quality, reduce health hazards, and improve antibacterial efficiency. Antibacterial packaging refers to adding antibacterial substances (antibacterial agents) to packaging materials. This antibacterial substance can be gradually released from the packaging material to the surface of the food to control the growth of microorganisms in the food. A packaging technology.

[0003] Ryegrass is a perennial plant with culms 30-90 cm high and soft roots at the base nodes. The ligule is about 2 mm long; the leaves are soft, with fine hairs, sometimes with ear. The spike-shaped inflorescence is erect or slightly curved; the spikelet axis is smooth and hairless; the glumes are lanceolate, with narrow membranous margins; the lemma is oblong, herbaceous, smooth, and without awns at the top; the two ridges have short cilia. The caryopsis is about 3 times longer than it is wide. Flowering and fruiting period is May-July. Summary of the invention

[0004] The purpose of the present invention is to develop a method for preparing an antibacterial and antiviral packaging material and a packaging material using the same. By extracting effective active ingredients from ryegrass and mixing them with modified polylactic acid, an antibacterial and antiviral packaging material is prepared, and the packaging material also has the advantages of sustained release and biodegradability.

[0005] According to one aspect of the present invention, a method for preparing an antibacterial and antiviral packaging material is provided, and the preparation of the antibacterial and antiviral packaging material comprises the following steps:

[0006] S1: extracting ryegrass leaves using a solvent to obtain ryegrass extract;

[0007] S2: dissolving the obtained ryegrass extract with a solvent and mixing it with modified mesoporous silica to obtain a nano drug-carrying material;

[0008] S3: The obtained nano drug-carrying material is mixed with modified polylactic acid, and then mixed with an organic solvent to prepare a spinning solution, which is spun into a film through an electrostatic spinning process to obtain the antibacterial and antiviral packaging material.

[0009] Compared with traditional food packaging, the preparation method of the present invention reduces the demand for active substances in ryegrass by adding active substances of ryegrass to packaging materials, compared with the traditional food preservation method of directly adding chemical preservatives to food. Moreover, the present invention combines the ryegrass extract with the polylactic acid modified with the camellia shell after specific treatment, and forms a packaging film with certain mechanical strength and barrier properties through the chemical bonding between the two; the flavonoid active substances in the ryegrass extract can complement the antibacterial spectrum of the modified polylactic acid, improve the antibacterial ability of the antibacterial film, and the synergistic effect of the two plays a sustained release effect on the release of the antibacterial agent, prolongs the antibacterial time, and achieves the purpose of active packaging. Moreover, the film formed by spinning of the present invention is sustained-release, degradable, highly breathable, and highly hydrophobic, and has broad application prospects in new food packaging materials in the post-epidemic era.

[0010] Preferably, in step S1, the main effective active ingredients of the ryegrass extract are flavonoid compounds, including at least one of prunin, acteoside, and 5,7-dihydroxydihydroflavone.

[0011] Preferably, the main effective active ingredients of the ryegrass extract also include at least one of 3-O-β-sitosterol glycoside, 7-methoxyauricularin, 5-[5-methyl-5-(4-methyl-2-oxopentyl)-tetrahydrofuran-2-yl]-1H-pyrrol-2(3H)-one, 3,4'-dimethoxy-3',5,7-trihydroxyflavone, myoporumine A, myoporumine B, (3R)-oct-1-en-3-ol-O-β-D-glucopyranosyl-(1"→2')-O-β-D-glucopyranoside, etc.

[0012] Preferably, in step S1, ryegrass leaves are first extracted using a solvent with low polarity and then using a solvent with high polarity, wherein the solvent is selected from n-hexane, petroleum ether, ethyl acetate, acetone, ethanol, and water. The polarities of the above solvents are arranged from small to large as follows: n-hexane < petroleum ether < ethyl acetate < acetone < ethanol < water. This method utilizes a solvent with high polarity to re-extract the extract of the solvent with low polarity, which can further concentrate the extract. Compared with the traditional extraction process, the present invention adopts a method of extracting the extracting solvent in batches from low polarity to high polarity, so that inactive or less active substances such as oils and fats in the powder are extracted first, thereby increasing the content of active ingredients in the extract during the subsequent extraction process, and achieving more accurate and effective extraction of active substances.

[0013] Preferably, in step S1, the leaves are dried and crushed before extraction to obtain ryegrass leaf powder. Compared with the traditional extraction process, this method is more conducive to the extraction operation, and can greatly retain the content of active ingredients in the extract while improving the extraction rate; and the powder after crushing has a small particle size and can be fully mixed and contacted with the extraction solvent, thereby increasing the extraction amount of effective active ingredients in the extraction process.

[0014] Preferably, in step S1, the mass ratio of the ryegrass leaves to the solvent is 1:5-7, the extraction temperature is 75-90°C, and the extraction time is 20-40 minutes. Under this ratio, temperature and time, the effective components in the ryegrass extract, such as flavonoids, etc., can be better obtained, and the effective active components will not be destroyed by high temperature.

[0015] Preferably, in step S1, the extract formed by ryegrass leaves and solvent needs to be vacuum filtered and then rotary evaporated at 40-50° C. Through vacuum filtration and low-temperature rotary evaporation, it is possible to remove excess powder and solvent to obtain ryegrass extract containing active ingredients, and it is also possible to ensure that the extraction of effective active ingredients is carried out at a lower temperature, thereby ensuring the activity of the effective ingredients.

[0016] Preferably, in step S2, the mass ratio of the modified mesoporous silica to the ryegrass extract is 1:0.8-1.2. As a carrier of the ryegrass extract, the modified mesoporous silica not only has a large specific surface area and pore volume, which increases its loading capacity, but also has two active groups, amino and carboxyl, which can be coupled with the extracted active substances, so that the active substances are loaded or adsorbed on the surface and inside of the mesoporous silica, forming a uniform and stable system, which is beneficial to improve the stability of the active substances and has a sustained release effect.

[0017] Preferably, in step S2, the detailed steps are: use anhydrous ethanol to dissolve the obtained ryegrass extract, add modified mesoporous silica, first ultrasonically treat for 10 to 20 minutes, then stir for 1.0 to 2.0 hours, then continue to stir for 15 to 25 minutes under vacuum, then shake for 20 to 30 hours, and then centrifuge at 9000 rpm for 30 minutes to obtain a nano drug delivery material.

[0018] Preferably, in step S2, preparing the modified mesoporous silica comprises the following steps:

[0019] According to the mass volume ratio of mesoporous silica: xylene = 1:90-110, a silane coupling agent is added and mixed for 20-28 hours, and then dried to obtain a mixture;

[0020] The mixture is mixed at a mass ratio of 1:20 to obtain a toluene mixture, 6 to 7 mmol of succinic anhydride is added to every 100 ml of the toluene mixture, and the mixture is stirred for 20 to 28 hours, followed by drying to obtain the modified mesoporous silica.

[0021] Preferably, in step S3, the modified polylactic acid is camellia oleifera shell modified polylactic acid, and the preparation of the camellia oleifera shell modified polylactic acid comprises the following steps:

[0022] The camellia oleifera shell powder is treated with alkali solution, and then mixed with a silane coupling agent for modification. The modified camellia oleifera shell powder is then mixed with polylactic acid to obtain camellia oleifera shell modified polylactic acid, wherein the content of the modified camellia oleifera shell is 3-8wt% by mass.

[0023] Among them, camellia oleifera shells contain tannins, saponins, flavonoids and other substances. Therefore, after the polylactic acid is modified by the camellia oleifera shells, the polylactic acid modified by the camellia oleifera shells has antibacterial, antioxidant and antiviral effects, and can work together with the effective active ingredients in ryegrass to achieve a synergistic improvement in the antibacterial effect. In addition, the modified polylactic acid modified by the camellia oleifera shells has stronger hydrophobicity. At the same time, as an agricultural and forestry waste, the addition of camellia oleifera shells to products not only greatly enhances the biodegradability of the products, but also realizes the resource utilization of camellia oleifera shells, which is of great significance for environmental protection.

[0024] Preferably, in step S3, the organic solvent is a mixed solvent, wherein the mixed solvent has a mass ratio of dichloromethane:N,N-dimethylformamide=1.2-1.8:1.

[0025] Preferably, in step S3, the spinning solution comprises, by mass percentage, 0.25-0.4 wt% of nano drug-carrying material and 6-9 wt% of camellia oleifera shell-modified polylactic acid.

[0026] Preferably, in step S3, the voltage of the electrospinning process is 17 KV, the spinning flow rate is 5 mL / h, the spinning receiving distance is 10 cm, and the spinning time is 3 h.

[0027] According to one aspect of the present invention, an antibacterial and antiviral packaging material is provided. The antibacterial and antiviral packaging material is prepared by the above-mentioned method for preparing the antibacterial and antiviral packaging material.

[0028] Preferably, the antibacterial and antiviral packaging material can inhibit the viral activity of SARS-CoV-2.

[0029] Preferably, the antibacterial and antiviral packaging material can inhibit Escherichia coli and Staphylococcus aureus.

[0030] In summary, compared with the prior art, the solution provided by the present invention has the following beneficial effects:

[0031] (1) The preparation method of the antibacterial and antiviral packaging material provided by the present invention adopts a specific extraction method to extract the effective active ingredients of ryegrass, which is rich in flavonoids such as prunin, phylloside, and 5,7-dihydroxyflavone. By using molecular simulation docking technology, it is proved that prunin, phylloside, and 5,7-dihydroxyflavone have the effect of inhibiting the activity of SARS-CoV-2 virus, and also have the effect of inhibiting Escherichia coli and Staphylococcus aureus. The antibacterial and antiviral effects of the prepared antibacterial and antiviral packaging material are further enhanced by the synergistic effect of tea oil shell modified polylactic acid.

[0032] (2) The method for extracting active substances from ryegrass provided by the present invention is simple and convenient. By extracting the active substances in different polar solvents in batches, the active substances can be traced and extracted, thereby obtaining a ryegrass extract with antibacterial and antiviral properties.

[0033] (3) The present invention utilizes modified mesoporous silica with two active groups, amino and carboxyl, which can be coupled with the effective active substance loaded in ryegrass, so that the drug carrier can slowly release the effective active substance, which prolongs the shelf life of the active substance and greatly improves the antibacterial and antiviral period of the packaging material;

[0034] (4) The present invention utilizes tea oil shell modified polylactic acid as a spinning substrate, and the resulting antibacterial and antiviral packaging film has strong hydrophobicity, high porosity, high air permeability, and is biodegradable. In addition, due to the raw materials and methods used to prepare the packaging film, the prepared packaging material has both antibacterial and antiviral effects, and can be applied to the field of new generation active food packaging. It can not only avoid adding chemical preservatives to food, but also provide food with antibacterial, antioxidant and antiviral effects.

[0035] Therefore, the present invention discloses a method for preparing an antibacterial and antiviral packaging material and a packaging material using the same. By using a fractional extraction method, the effective active substances of ryegrass are extracted and then prepared with mesoporous silica to prepare a nano drug-carrying material, and then the drug carrier and the tea shell modified polyemulsion are compounded in a certain proportion to prepare an antibacterial and antiviral packaging material, and the material can be used in the food packaging industry and can be used for various types of packaging such as fruits, seafood, and takeout. In particular, the antibacterial and antiviral packaging material provided by the present invention can prevent the invasion of the new coronavirus and inhibit the activity of Escherichia coli and Staphylococcus aureus. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a flow chart of the preparation method of the present invention;

[0037] Figure 2A docking diagram showing some active compounds and therapeutic targets related to SARS-CoV-2;

[0038] Explanation of numbers: A. 3D display of docking between structure No. 1 and target 6LU7, B. 2D display of docking between structure No. 1 and target 6LU7, C. 3D display of docking between structure No. 2 and target 6LU7, D. 2D display of docking between structure No. 2 and target 6LU7, E. 3D display of docking between structure No. 3 and target 6LU7, F. 2D display of docking between structure No. 3 and target 6LU7. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the drawings in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0040] Example 1

[0041] 1. Preparation of modified mesoporous silica

[0042] First, mesoporous silica and xylene were mixed, and the mass volume ratio was mesoporous silica: xylene = 1:100. 100 mL of the mixture was taken, and 6 mmol of silane coupling agent (KH-550) was added dropwise thereto. After ultrasonication, vacuum was drawn, and the mixture was slowly stirred and reacted for 24 hours. The filter cake was washed alternately with methanol and xylene, and dried to obtain a mixture. The mixture was then mixed with toluene, and the mass ratio was mixture: toluene = 1:20, and a toluene mixture was obtained. Then 6.6 mmol of succinic anhydride was added to 100 ml of the toluene mixture, stirred and reacted for 24 hours, and vacuum dried at room temperature to obtain modified mesoporous silica.

[0043] 2. Preparation of polylactic acid modified with camellia oleifera shell

[0044] (1) Alkali treatment of camellia oleifera shell and its modification: The camellia oleifera shell powder was placed in a 5% NaOH solution and stirred at 500 rpm for 4 h at 25°C. After stirring, it was washed with deionized water and filtered to obtain an alkali-treated powder. The alkali-treated camellia oleifera shell powder was then mixed with a silane coupling agent for modification in a mass ratio of 5:1. The mixture was stirred at 80°C for 4 h. After ultrasonic treatment for 30 min, the mixture was filtered and dried to obtain the modified camellia oleifera shell powder.

[0045] (2) Preparation of camellia oleifera shell modified polylactic acid: The modified camellia oleifera shell powder was mixed with polylactic acid using a high-speed mixer, wherein the mass ratio of modified camellia oleifera shell powder to polylactic acid was 1:19. The mixture was then melt-blended and extruded using a co-rotating twin-screw extruder, and pelletized using a matching pelletizer to obtain a composite material.

[0046] 3. Preparation of packaging film with antibacterial and antiviral properties

[0047] S1: Dry and crush fresh ryegrass leaves, take 200 g of dry powder, extract with n-hexane, according to the mass volume ratio of ryegrass leaves: solvent = 1:6, the extraction temperature is 70°C, the extraction time is 30 min, extract three times and filter, collect the extracted dry powder, and then extract with petroleum ether in the same proportion and steps, the extraction temperature is 75°C, collect the extract after filtration, and rotary evaporate at 42°C to obtain the petroleum ether phase active extract.

[0048] S2: Dissolve 1g of the extract in 5g of anhydrous ethanol and mix it with modified mesoporous silica in a mass ratio of modified mesoporous silica: ryegrass extract = 1:1. After ultrasonic treatment for 15min, stir magnetically for 1.5h, and then stir in a vacuum chamber for 20min. Place the mixture in a constant temperature shaker for 24h to allow the active substances to enter the pores of the modified mesoporous silica. Centrifuge at 9000rpm for 30min to obtain a nano drug delivery material.

[0049] S3: 0.08g of the nano drug-carrying material and 2g of the modified polylactic acid material were mixed in 25g of a mixed solvent, wherein DCM:DMF=1.5:1 in the mixed solvent according to mass percentage, and the mixture was stirred at 40°C to prepare a spinning solution. The spinning solution was drawn with a 25mL sterile syringe, and the fiber was spun on an electrospinning machine with set parameters, including a voltage of 17KV, a flow rate of 5mL / h, a receiving distance of 10cm, and a spinning time of 3h, and the fiber was received on a rotating drum with tin foil (speed of 1200r / min) to obtain a packaging film with antibacterial and antiviral properties.

[0050] Example 2

[0051] Take 200 g of the dry powder extracted with petroleum ether in Example 1 and extract it with ethyl acetate. According to the mass volume ratio, the dry powder extracted with petroleum ether: solvent = 1:6, the extraction temperature is 85°C, the extraction time is 30 min, and after three extractions, filter and collect the extract. Rotary evaporate at 35°C to obtain an active extract in the ethyl acetate phase.

[0052] This treatment group prepared modified mesoporous silica, tea shell modified polylactic acid and packaging film with antibacterial and antiviral properties by referring to the formula and method provided by treatment group 1. Except for the above differences, the method used by this treatment group to prepare the packaging film with antibacterial and antiviral properties was strictly consistent with Example 1.

[0053] Example 3

[0054] Take 200 g of the dry powder after ethyl acetate extraction in Example 2, extract with anhydrous ethanol, according to the mass volume ratio, the dry powder after ethyl acetate extraction: solvent = 1:6, the extraction temperature is 90°C, the extraction time is 30 min, extract three times and filter, collect the extract, and rotary evaporate at 40°C to obtain an anhydrous ethanol phase active extract.

[0055] This treatment group prepared modified mesoporous silica, tea shell modified polylactic acid and packaging film with antibacterial and antiviral properties by referring to the formula and method provided by treatment group 1. Except for the above differences, the method used by this treatment group to prepare the packaging film with antibacterial and antiviral properties was strictly consistent with Example 1.

[0056] Comparative Example 1

[0057] 2g of polylactic acid material was mixed in 25g of mixed solvent, and DCM:DMF in the mixed solvent was 1.5:1 according to mass percentage, and the spinning solution was prepared by stirring at 40°C. The spinning solution was sucked with a 25mL sterile syringe, and the fiber was spun on an electrospinning machine with set parameters, including voltage of 17KV, flow rate of 5mL / h, receiving distance of 10cm, and spinning time of 3h, and received on a rotating drum with tin foil (speed of 1200r / min) to obtain a polylactic acid film.

[0058] Comparative Example 2

[0059] 2g of polylactic acid material modified by camellia oleifera shell was mixed in 25g of mixed solvent, and DCM:DMF in the mixed solvent was 1.5:1 according to mass percentage, and the spinning solution was prepared by stirring at 40°C. The spinning solution was drawn with a 25mL sterile syringe, and the fiber was spun on an electrospinning machine with set parameters, including voltage of 17KV, flow rate of 5mL / h, receiving distance of 10cm, and spinning time of 3h, and received on a rotating drum with tin foil (speed of 1200r / min) to obtain a polylactic acid film modified by camellia oleifera shell.

[0060] In this comparative example 2, the formula and method provided in reference example 1 were used to prepare camellia oleifera shell modified polylactic acid.

[0061] Comparative Example 3

[0062] 1g of mesoporous silica and 1g of polylactic acid material modified by camellia oleifera shell were mixed in 25g of mixed solvent, and DCM:DMF in the mixed solvent was 1.5:1 according to mass percentage, and the spinning solution was prepared by stirring at 40°C. The spinning solution was sucked with a 25mL sterile syringe, and the fiber was spun on an electrospinning machine with set parameters, including voltage of 17KV, flow rate of 5mL / h, receiving distance of 10cm, and spinning time of 3h. The fiber was received on a rotating drum with tin foil (speed of 1200r / min) to obtain a porous camellia oleifera shell modified polylactic acid membrane.

[0063] This comparative group prepared tea oil shell modified polylactic acid and mesoporous silica according to the formula and method provided in Example 1.

[0064] Test Example 1

[0065] 1. Test subjects

[0066] After testing, the main active ingredients in ryegrass extract are flavonoids, which can effectively inhibit the replication activity of SARS-CoV-2, including at least one of prunin, actinoside, 5,7-dihydroxydihydroflavone, 3-O-β-sitosterol glycoside, 7-methoxycitronellal, 5-[5-methyl-5-(4-methyl-2-oxopentyl)-tetrahydrofuran-2-yl]-1H-pyrrol-2(3H)-one, 3,4'-dimethoxy-3',5,7-trihydroxyflavone, (3R)-oct-1-en-3-ol-O-β-D-glucopyranosyl-(1"→2')-O-β-D-glucopyranoside, myoporumine A, and myoporumine B.

[0067] Among them, the test objects are structure No. 1 prunin, structure No. 2 acteoside, and structure No. 3 5,7-dihydroxydihydroflavone.

[0068] 2. Test Method

[0069] This test example is a simulation docking of the novel coronavirus molecule. Some of the compound structures in the active ingredients of the extracts of treatment groups 1A to 3A in Example 1 were imported into Discovery Studio 2017, and the minimize module was used to optimize the drug structure. The optimized small molecule structure was imported into the receptor-ligand interaction module for molecular docking using the CDOCKER algorithm.

[0070] 3. Test results

[0071] Among them, the molecular structures of compounds 1, 2, and 3 are as follows, and the molecular docking results of compounds 1, 2, and 3 are as follows Figure 2 The docking results are shown in Table 1:

[0072]

[0073] Among them, (1) is the molecular structure No. 1 prunin, (2) is the molecular structure No. 2 acteoside, and (3) is the molecular structure No. 3 5,7-dihydroxydihydroflavone.

[0074] Table 1 Molecular docking result evaluation table

[0075]

[0076]

[0077] The new coronavirus (SARS-CoV-2) belongs to the beta coronavirus, and there are 11 functional genes encoding structural proteins, non-structural proteins and auxiliary proteins. Among them, the non-structural proteins include two important proteins, Mprofrom SARS-CoV-2 (Mpro) and SARS-CoV-2 RNA-directed RNA polymerase (RdRp). These two proteins are involved in the replication and transcription of the virus. After the virus infects the cell, it enters the cell by interacting with the host cell protein. At present, the protein in the body that is more clearly related to the new coronavirus is angiotensin-converting enzyme 2 (ACE2). Based on this mechanism, the current screening of small molecule drugs that are effective in inhibiting the activity of SARS-CoV-2 mainly focuses on Mpro, RdRp and ACE2.

[0078] In Table 1, the molecular structure numbers are Figure 2 Correspondingly, 6LU7, 6XQB, and 2AJF are the PDB IDs of the three COVID-19-related therapeutic targets (Mpro, RdRp, and ACE2) that have been confirmed. -CDOCKER INETRNATION ENERGY is an evaluation indicator of the molecular docking results under the CDOCKER algorithm. This molecular docking only uses energy value as a measurement indicator. The larger the value, the better the result is generally considered. Combined with Figure 2 The results in Table 1 show that the extracted active compounds are mainly involved in the replication and transcription of the new coronavirus. The targets are mainly concentrated on the two proteins Mpro and RdRp. Among them, the No. 2 structural phyllotoxin has a stronger effect on the targets 6LU7 and 6XQB.

[0079] Test Example 2

[0080] 1. Test subjects

[0081] (1) The extracts of the effective active ingredients obtained in Examples 1 to 3 were tested for antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus);

[0082] (2) The antibacterial and antiviral packaging films prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to antibacterial tests using the inhibition zone method.

[0083] 2. Test Method

[0084] (1) The extracts of effective active ingredients obtained in Examples 1 to 3 were respectively subjected to MIC determination by the multiple dilution method. The determination method is as follows: 1 g of each extract was diluted to 0.39 mg / mL by multiple dilution method, and then the same amount of bacterial suspension was added to the extracts of each tube with different dilutions. A physiological saline control group was set up at the same time. After each tube was mixed evenly, 100 μL of each was drawn and coated on the surface of the culture medium plate, and cultured in a 37°C incubator for 24 hours. The growth of colonies on the surface of the culture medium was observed. The minimum inhibitory concentration of the extract in the sterile growth medium is the minimum inhibitory concentration, that is, the MIC of the extract.

[0085] (2) The films prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to antibacterial tests using the inhibition zone method. The specific method is as follows: the films were prepared into 6 mm discs using a sterile puncher, 150 μL of the bacterial suspension was aspirated under sterile conditions, and evenly spread on the corresponding culture medium, and the discs were spread flat on the bacterial culture dishes, 3 discs per dish, and repeated 3 times. After culturing for 24 hours, the diameters of the inhibition zones in two perpendicular directions were measured using a vernier caliper, and the data were recorded to obtain the average result.

[0086] 3. Test results

[0087] (1) Antibacterial effect of extracts of active ingredients from ryegrass

[0088] The results shown in Tables 2 and 3 show that the active extracts of ryegrass contained in Examples 1 to 3 have significant antibacterial effects, and the antibacterial effects of the active substances extracted by solvents of different polarity are significantly different. The active extracts obtained in Examples 1 and 3 show a strong antibacterial effect on Escherichia coli (E.coli), and the MIC value is 1.56 mg / mL. In addition, the active extract contained in Example 2 has a strong antibacterial effect on Staphylococcus aureus (S.aureus), and the MIC value is 3.13 mg / mL. This may be due to the extraction of different polar solvents in batches, resulting in different active substances obtained in batches, which further affects the activity of the effective ingredients.

[0089] Table 2 MIC determination results for E.coli

[0090]

[0091] Note: “++” indicates more bacterial growth; “+” indicates less bacterial growth; “-” indicates sterile growth.

[0092] Table 3 MIC determination results for S. aureus

[0093]

[0094]

[0095] Note: “++” indicates more bacterial growth; “+” indicates less bacterial growth; “-” indicates sterile growth.

[0096] (2) Antibacterial and antiviral packaging film’s antibacterial effect

[0097] It can be clearly seen from the results in Table 4 that compared with comparative examples 1 to 3, the antibacterial effects of embodiments 1 to 3 are significantly improved, among which the antibacterial circle of comparative example 1 is almost impossible to measure, the antibacterial circle of embodiment 3 is the largest, and the antibacterial circle of embodiment 2 is the largest. This may be because the fractional extraction of solvents with different polarity leads to different contents and components of the traced extracted active substances, and thus different antibacterial effects. In addition, the antibacterial effects in the embodiments are all better than those in the comparative examples, which is brought about by the synergistic effect of the effective active ingredients of ryegrass and the polylactic acid modified with oil tea shells.

[0098] Table 4 Antibacterial test results of membranes

[0099]

[0100] Note: “--” means the diameter of the inhibition zone cannot be measured.

[0101] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing an antibacterial and antiviral packaging material, characterized in that: The following steps are involved: S1: first extract the ryegrass leaves with a solvent having low polarity, and then extract the ryegrass leaves with a solvent having high polarity to obtain a ryegrass extract; wherein the solvent is selected from n-hexane, petroleum ether, ethyl acetate, acetone, ethanol, and water; the main active ingredient of the ryegrass extract is a flavonoid compound, including at least one of prunin, phylloside, and 5,7-dihydroxydihydroflavone; the extraction process comprises forming an extract with the ryegrass leaves and the solvent, extracting at 75 to 90° C. for 20 to 40 minutes, then vacuum filtering the extract, and performing rotary evaporation at 40 to 50° C. to obtain a ryegrass extract; calculated by mass ratio, the ryegrass leaves: the solvent = 1:5 to 7; S2: dissolving the obtained ryegrass extract with a solvent and mixing it with modified mesoporous silica to obtain a nano drug-carrying material; S3: The obtained nano drug-carrying material is mixed with tea oil shell modified polylactic acid, and then mixed with an organic solvent to prepare a spinning solution, and then spun into a film through an electrostatic spinning process to obtain the antibacterial and antiviral packaging material.

2. The method for preparing the antibacterial and antiviral packaging material according to claim 1, characterized in that: In step S2, the mass ratio of the modified mesoporous silica to the ryegrass extract is 1:0.8-1.

2.

3. The method for preparing the antibacterial and antiviral packaging material according to claim 1, characterized in that: In step S2, preparing the modified mesoporous silica comprises the following steps: According to the mass volume ratio of mesoporous silica: xylene = 1:90-110, a silane coupling agent is added and mixed for 20-28 hours, and then dried to obtain a mixture; The mixture is mixed at a mass ratio of 1:20 to obtain a toluene mixture, 6 to 7 mmol of succinic anhydride is added to every 100 ml of the toluene mixture, and the mixture is stirred for 20 to 28 hours, followed by drying to obtain the modified mesoporous silica.

4. The method for preparing the antibacterial and antiviral packaging material according to claim 1, characterized in that: In step S3, preparing the camellia oleifera shell modified polylactic acid comprises the following steps: The camellia oleifera shell powder is treated with alkali solution, and then mixed with a silane coupling agent for modification to obtain a modified camellia oleifera shell powder, which is then mixed with polylactic acid to obtain camellia oleifera shell modified polylactic acid, wherein the content of the modified camellia oleifera shell is 3-8wt% by mass.

5. The method for preparing the antibacterial and antiviral packaging material according to claim 1, characterized in that: In step S3, the organic solvent is a mixed solvent of dichloromethane and N,N-dimethylformamide, and the mass ratio of dichloromethane to N,N-dimethylformamide is 1.2 to 1.8:

1.

6. The method for preparing the antibacterial and antiviral packaging material according to claim 1, characterized in that: In step S3, the spinning solution includes, by weight percentage, 0.25-0.4 wt% of nano drug-carrying material and 6-9 wt% of camellia oleifera shell-modified polylactic acid.

7. An antibacterial and antiviral packaging material, characterized in that: The antibacterial and antiviral packaging material is prepared by the method for preparing an antibacterial and antiviral packaging material as claimed in any one of claims 1 to 6.

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