Study On The Extraction,Bacteriostasis Of Antibacterial Substances In Plant Materials And Its Application

With the rising of public awareness for food safety,consumers worry about latent dangers to human health caused by abuse of chemical food preservatives.Natural safe,high effective and nutritional food preservatives have been one hot spot of food science.The plant original food preservatives are one ideal food preservative with the advantages of natural safety,non-toxicity good antibacterial effect and other functions such as antioxidative effect and anti-aging effect etc.Using plant materials in resource both of medicine and food released by Health Ministry,antibacterial ingredients are extracted by modern separation technology,antibacterial effect and their application in food storage are investigated in this theis.As follows:(1)Eight plant materials are used to extract antimicrobial active ingredients using ethanol as extracting solvent.The antimicrobial effect of their ethanol extracts was studied by the Oxford cup method against some pathogens and spoilage bacteria commonly existed in foods.The results show that:ethanol extracts from eight plant materials have different antibacterial effect,Vaccinium bracteatum Thumb and Fructus Schisandrae Chinensis have the best inhibition effect on Staphylococcus aureus,and the maximum bacteriostatic diameter is more than 26 mm;clove and Fructus Schisandrae Chinensis have the strongest effect on mucor,and the maximum bacteriostatic diameter is more than 25 mm;But compared to other raw materias,the inhibition activity of the three kind of plants are still best.(2)Then,using Fructus Schisandrae Chinensis,clove and Vaccinium bracteatum Thunb,the optimum extraction process of antimicrobial active ingredients was further studid.The optimum extraction conditions were determined by single factor test and orthogonal test,with ethanol as extraction solvent,the results as follows:ethanol concentration 85%,temperature of 90 degrees centigrade,and solid-liquid ratio 1:18,6 hours for clove;ethanol concentration 85%,temperature of 85 degrees centigrade,and solid-liquid ratio 1:16,time of 5 hours for Fructus Schisandrae Chinensis;ethanol concentration 85%,temperature of 90 degrees centigrade,and solid-liquid ratio 1:16,4 hours for Vaccinium bracteatum Thunb.In the above extraction conditions,The main antibacterial component in Fructus Schisandrae Chinensis is measured to be 0.93%by HPLC;The content of active ingredients eugenol in clove is measured to be 3.29%by using of UV spectrophotometry;The main active antibacterial ingredient total flavonoid contentin in Vaccinium bracteatum Thunb is measured to be 3.95%by using of UV spectrophotometry.(3)We have further research on application of the three kinds of plants in keeping fresh of wheat flour food.The Abs,total plate count and pH of bacterial suspension are separately analyzed in certain time interval through spectrophotometric method and National standard method,when nourishing in a hot and humid.It turn out that the concentration of bacterial suspension is lower than the Sodium Dehydroacetate control group after had added Fructus Schisandrae Chinensis;experimental groups which added Fructus Schisandrae Chinensis and clove,and Sodium Dehydroacetate control group have consistent total plate count;The pH value of experimental group which added Fructus Schisandrae Chinensis and chemical preservatives control group is displayed in the edible range;In conclusion,Fructus Schisandrae Chinensis,clove and Vaccinium bracteatum Thunb have a certain antimicrobil effect in spoilage bacteria and micro-organisms on common food system.The extracting solution of Fructus Schisandrae Chinensis extends about 7 days on the shelf life of wheat flour foods and baked goods,and provides a scientific basis to explore the best cycle of inhibitory effect.