Separation、Screening And Application Of Probiotics From Natural Fermented Foods In Changbai Mountain Region

Changbai Mountain region is a gathering place for the Korean nationality, their major feature of the local is their diet. Natural fermented food is the Korean nationality’s traditional cuisine which has a long history. Fermented pickles contain a lot of beneficial microorganism, especially lactic acid bacteria(LAB). After long-term nature domesticated, lactic acid bacteria have became dominant bacterias in fermented food, they can be used as an excellent source of probiotics. This study is based on this purpose. Seven natural fermented products from Changbai Mountain region were collected from which separated and screened beneficial lactic acid bacteria, Iaided the foundation for the application of probiotics.Total63LABs were isolated from natural fermented foods in Changbai Mountain region.11of these strains were identified as Lactobacillus plantarum by API50CHL and16S rDNA sequence analysis. The probiotic properties of these11strains were studied, including acid and bile tolerance, the minimum inhibitory concentration of antibiotics, antibacterial activity against pathogens, adhesion ability to Caco-2cells and the ability of inhibition of pathogens to adhesion to Caco-2cells. Among the text strains, L. plantarum DH1-XHG-3showed good probiotic properties. L. plantarum DH1-XHG-3strain survived very well at the pH2.0and bile salt concentration0.5%conditions and showed sensitivity to11kinds of commonly used antibiotics. The strain also showed strong adhesion to Caco-2cells at the adhesion rate of9.89±0.74%which higher than L. rhamnosus GG, and the ability to inhibit the attachment of E. coli, Staphylococcus aureus, Salmonella typhimurium, and Shigella flexneri to Caco-2cells under the conditions of competition, inhibition and displacement.In addition, this study determined the fermentation characteristics of DH1-XHG-3. The results showed that this exopolysaccharide producted strain had good somatic cell activity and proteolytic activity. These results indicate that L. plantarum DH1-XHG-3could be considered as a promising probiotic strain which used in fermented products.Though these studies, we got one strain DH1-XHG-3with excellent probiotic characteristics and fermentation characteristics which used in yogurt fermentation process as an auxiliary agent. Then probiotic yogurt containing L. plantarum DH1-XHG-3was made. The results of sensory evaluation of yogurt showed yogurt containing DH1-XHG-3had good organization of the state, no bad smell and tasted smoothly. During the21days of storage at4℃, the strain DH1-XHG-3 survived well in the yogurt, and the number of the strain was higher than108cfu/mL. The results of physical and chemical, such as pH, titratable acidity, texture features and water retention, showed that the texture features and water retention of the yogurt containing DH1-XHG-3was higher than the control group, and there were no significant differences in pH and titratable acidity.