Functional characteristics of lactobacilli from traditional Bulgarian fermented milk products

Abstract

After oral administration, probiotic lactobacilli meet a number of protection systems in the human body, such as exposure togastric, pancreatic, and small intestinal juices. Overcoming these detrimental barriers allows living bacteria to adhere to the intestinalepithelium and permanently colonize the gastrointestinal tract (GIT), providing health benefits to the host. Based on this, the transittolerance of 25 candidate probiotic lactobacilli from katak, yoghurt, and white-brined and yellow cheese to simulated bile and smallintestinal juices of variable pH was investigated. To establish their resistance, in vitro model systems based on modified MRS mediaand a longer duration of action (up to 24 h of incubation) were designed. Six of the strains studied were found to show strain-specificsurvival capacity with low viability in conditions simulating stomach acidity and high resistance to bile and intestinal juices. In addition,the adherence capability (autoaggregation and hydrophobicity) of the strains was determined. Obtained results allowed to selectLactobacillus strains with high survival ratios while passing through the GIT and good adherence properties, which make them suitablefor the development of new probiotics.