The Extraction Of Botanical Bactericides And Their Application On Edible Film

The effects of different extract methods and solvents on the extraction ratio ofalkaloids in sophora flavescens were investigated in this paper. The effect of ethanolas solvent is better than pure water and5%acetic acid solution, and the microwave-assisted extraction ratio was higher than traditional reflux method when the samesolvent was used in the experiment. The bactericidal property of sophora flavescensextract can be affected by many factors due to the complication of bactericidalsubstances. So, the effects of temperature, ethanol concentration, solid-liquid ratio,extracting times on antimicrobial performance were evaluated and the optimumextraction conditions were selected by bacterial inhibition ring test. The resultsshowed that the extract that had the best antimicrobial property could be got when thesophora flavescens was extracted in45%ethanol （solid-liquid ratio was1:12） for4times at70℃.The bactericidal properties of sophora flavescens, clove, cinnamon and theircompounds on the Staphylococcus aureus and Escherichia coli were evaluated. Thestudy indicated that the bactericidal property of cinnamon was stronger than sophoraflavescens and clove, and cinnamon had a greater increase in bactericidal propertythan the other two kinds of bactericide when their concentrations increased. Thecombination of cinnamon oil with clove oil had additive effect on Escherichia coliand the best ratio of clove and cinnamon was8:1. Furthermore, the mixture showedsynergistic effect on Staphylococcus aureus and the best ratio was2:1. However, thecombination of sophora flavescens with cinnamon and clove had no correlative effecton both of the bacteria.The antimicrobial edible film was prepared by using sodium alginate as basematerial and glycerol as the plasticizer. The mixture of cinnamon oil and clove oil wasused as bactericide while Tween80acted as the emulsifier. Besides, CaCl₂solutionwas used as the cross-linking agent. The dosages of different materials in the film mayhave different impacts on the mechanical property, bactericidal property and filmthickness of the film. Tween80, essential oil as well as glycerol could reduce theintermolecular forces along polymer chains, and thus reduce the tensile strength and increase elongation at break. The increase of the content of Tween80and glycerolincreased the film thickness, but it had no great effect on the bactericidal property,while the addition of essential oil could increase the bactericidal property of the filmsignificantly. The tensile strength and film thickness rose but the elongation at breakand bactericidal property ascended firstly and then descended with the adding ofsodium alginate. The result also showed that the tensile strength and elongation atbreak increased and then went down with increasing concentration of CaCl₂, and thehigher film thickness was associated with higher concentration of CaCl₂. What’s more,the bactericidal property of uncrosslinked film was stronger than the crosslinked filmobviously. The result for the edible film showed that the prepared film could get betterproperties when the amount of raw materials were as follows: Tween802%, essentialoil2%, sodium alginate3%, glycerol1%and CaCl₂5%.