SRA

The research in the frame of Croatian Science Foundation project entitled „Probiotics and starter cultures – surface proteins and bacteriocins“ is aimed to deliver new generation of probiotics and functional starter cultures, thoughtfully characterised and with specific features such as production of functional surface (S)-layer proteins and bacteriocins with broad spectrum of activity towards potential food contaminants and pathogens. Among more than 200 different LAB strains isolated from artisanal fermented food products in Laboratory of Antibiotic, Enzyme, Probiotic and Starter Culture Technologies, Faculty of Food Technology and Biotechnology University of Zagreb, only few of Lactobacillus strains are found to possess S-layer proteins on the cell surface, among which Lactobacillus helveticus M92, Lactobacillus brevis ZG1, Lactobacillus brevis SF9B and Lactobacillus brevis SF15B. Importance of S-layer proteins lies in increasing scientific evidences that some probiotic properties of lactic acid bacteria (LAB), such as enhanced survival in rigorous conditions in gastrointestinal tract and during the process of freeze-drying, adhesion to intestinal epithelial cells or inhibition of pathogens, are related to the occurrence of those proteins. Hence, it is believed that the production of S-layer proteins might be a selective criterion indicating probiotic effect of Lactobacillus species that express those specific surface proteins. Another feature specific to certain strains of LAB, which gives them a selective advantage when applied as probiotic or starter cultures, is the production of bacteriocins. Among all the isolated autochthonous LAB, three Lactobaillus plantarum strains, M92C, SF15C and D13, showed advanced bacteriocinogenic potential. Besides their application as probiotics, these strains could be considered as starter cultures with potential to improve the functionality and quality of various fermented products, while in the same time preserving their traditional sensory characteristics.