Preparation And Properties Of Chitosan Antibacterial Membrane Based On Litsea Cubeba Essential Oil

Litsea cubeba oil,as a natural plant essential oil in China,is widely used in our lives.Its main component,citral,has a lemon-flavored scent,is edible,non-toxic,and has strong antibacterial properties.It has great prospects for development and utilization.However,they all have the disadvantages of pungent odor,easy volatility,and unstable properties.Chitosan is a basic cationic polysaccharide.It is the second most abundant natural polymer on earth after cellulose.It has good film-forming and affinity and is non-toxic and edible.In this paper,a new type of antibacterial membrane was prepared by mixing chitosan with essential oil of Litsea cubeba,in order to achieve the antibacterial effect of slow-releasing essential oil of Litsea cubeba,and improve the physical properties of a single chitosan membrane.Different concentrations of antibacterial membrane are added with different concentrations of Litsea cubeba oil or citral,and then the thickness,density,light transmittance,mechanical properties,water vapor permeability,water solubility,volatile,and thermal stability are added to them.And scanning electron microscope to observe its surface morphology.Explore the antibacterial activity of different proportions of antibacterial membranes on Gram-negative bacteria,Gram-positive bacteria,molds and beneficial bacteria.The following results were obtained through experiments(1)Preparation of chitosan antibacterial membrane based on Litsea cubeba essential oil: Orthogonal experiment results in four ratios.Analysis using tensile strength of mechanical indicators as the evaluation standard: Chitosan antibacterial membrane based on 2% essential oil of Litsea cubeba.The best ratio to obtain the antibacterial membrane of chitosan essential oil based on Litsea cubeba is 1% of glycerol concentration,1.75% of chitosan concentration,1% of glacial acetic acid concentration and 0.5% of Tween-80 concentration.Later called it the ratio of tensile strength of Litsea cubeba(Litsea cubeba TS,LCTS).The best ratio of chitosan antibacterial membrane based on 2% citral is to get 1% glycerol concentration,1.5% chitosan concentration,and glacial acetic acid concentration.1%,Tween-80 concentration is 1%,hereinafter referred to as citral tensile strength ratio(Citral TS,CTS).Analysis using elongation at break of mechanical indicators as the evaluation standard: The best ratio of chitosan antibacterial membrane based on 2%essential oil of Litsea cubeba.The best ratio to obtain the antibacterial membrane of chitosan essential oil based on Litsea cubeba is 3% of glycerol concentration,1.25% of chitosan concentration,0.75% of glacial acetic acid concentration and 0.5% of Tween-80 concentration.Later called it the ratio of tensile strength of Litsea cubeba(Litsea cubeba EAB,LCEAB).The best ratio of chitosan antibacterial membrane based on 2% citral is 3%glycerol concentration,1.25% chitosan concentration,1% glacial acetic acid concentration and 0.5% Tween-80 concentration This concentration is the best ratio,which is hereinafter referred to as the ratio of citral elongation at break(Citral EAB,CEAB).(2)For the selected LCTS、CTS、LCEAB and CEAB ratios,add 0.5%,1%,1.5%,and 2% concentrations of Litsea cubeba oil or citral to determine the physical properties of the antibacterial membrane.With the increase of the concentration of essential oil and citral,the thickness is getting larger and larger,the density is getting smaller and smaller,the light transmittance is also decreasing,the elongation at break value is increasing,and the water vapor transmission coefficient is gradually increasing.The volatile matter content of the antibacterial membrane and the water solubility of the antibacterial membrane have no great influence.LCEAB antibacterial film has the largest volatile content,ranging from 60.57% to 64.18%,while CTS has the largest water solubility is between 53.04% and 55.29%.With the increase of the concentration of Litsea cubeba or citral added to these four ratios,the surface is no longer smooth,wrinkles occur,and the thermal stability is relatively improved.(3)The selected antibacterial membrane solutions of LCTS、CTS、LCEAB and CEAB were selected against Gram-negative bacteria: Escherichia coli,Pseudomonas putida,Gram-positive bacteria: Staphylococcus aureus,Bacillus subtilis;mold: Aspergillus niger,Trichoderma viride;beneficial bacteria: Saccharomyces cerevisiae,Bacillus subtilis was tested for bacteriostasis,and the results were all bacteriostatic.The bacteriostatic membrane solution with citral is generally more effective than the bacteriostatic membrane solution with essential oil of Litsea cubeba.The 2% concentration of CTS bacteriostatic membrane has better bacteriostatic effect on Pseudomonas putida,Trichoderma viride,Saccharomyces cerevisiae,and Bacillus subtilis.Bacteriostatic diameters are 23.43 mm,75.62 mm,18.81 mm,20.65 mm.The 2% concentration of CEAB bacteriostatic membrane has better bacteriostatic effect on Aspergillus niger,the bacteriostatic diameter is 30.16 mm.The 2% concentration of LCEAB bacteriostatic membrane has better bacteriostatic effect on Escherichia coli,the bacteriostatic diameter is 25.17 mm.The 2% concentration of LCTS antibacterial membrane has better antibacterial effect on Staphylococcus aureus,the bacteriostatic diameter is 25.79 mm.