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The aim of this work was to characterize the functional properties of Enterococcus faecium strains identified after isolation from human faeces. Of these isolates, strain R13 showed the best resistance to low pH, bile salts, and survival in the simulated in vitro digestion assay, and demonstrated an important level of adhesion to hexadecane as a potential probiotic candidate. Analysis of the antibiotic resistance of E. faecium strains indicated that in general these isolates were sensitive to the tested antibiotics and no strain appeared to be resistant to vancomycin. Examination of the virulence determinants for E. faecium strains demonstrated that all strains contained the virulence genes common in gut- and food-originated enterococci, and strain R13 harboured the lowest number of virulence genes. Additionally, no strain contained the genes related to cytolysin metabolism and showed hemolytic activity. The antimicrobial role of E. faecium strains was tested against several pathogens, in which different levels of inhibitory effects were observed, and strain R13 was inhibitory to all tested pathogens. PCR screening of genes encoding enterocin A and B indicated the presence of these genes in E. faecium strains. Preliminary characterization of bacteriocins revealed that their activity was lost after proteolytic enzyme treatments, but no alteration in antimicrobial activity was observed at different pHs (3.5 to 9.5) and after heat treatments. In conclusion, this study revealed the functional characteristics of E. faecium R13 as a gut isolate, and this strain could be developed as a new probiotic after further tests.

This study aimed to isolate and identify yeast species from kefir samples and to determine their probiotic characteristics in comparison with commercial probiotic yeast Saccharomyces boulardii. The microbial flora of traditional kefir samples were dominated by Saccharomyces cerevisiae and Kluyveromyces marxianus. Kefir isolates demonstrated higher auto‐aggregation, hydrophobicity and antioxidant properties compared to S. boulardii although S. boulardii demonstrated the highest survival rate under in␣vitro gastrointestinal digestion conditions followed by two kefir yeasts K. marxianus and Kazachstania unispora. Importantly, kefir isolates revealed strong antifungal activities against mould species except Penicillium roqueforti. These findings suggest probiotic and functional roles of yeast strains isolated from traditional kefir samples.

Exopolysaccharides (EPS) of lactic acid bacteria are important biopolymers that can improve the physicochemical properties of food products and act as prebiotics. In this study the physicochemical role and the prebiotic effects of a glucan type EPS with (α1-3) and (α1-6) linkages were assessed in chocolate pudding containing GG as a probiotic strain. The functions of EPS were determined by developing three different formulations: control, probiotic ( GG) and symbiotic pudding ( GG + EPS) samples. The pH and acidity of the symbiotic pudding sample were higher than the probiotic and the control samples during the 28-day of storage period. Similarly, an important level of increment in GG levels in symbiotic sample was observed compared to the probiotic sample suggesting the prebiotic role of the α-glucan. Importantly, the syneresis in symbiotic pudding sample reduced significantly compared to other pudding samples which is related with the physicochemical role of glucan type EPS. This study reveals the prebiotic and physicochemical roles of α-glucan type EPS in a chocolate pudding model.