Abstract
Postbiotics are functional bioactive substances manufactured during fermentation in a food matrix, which can be used to improve human health, but their influence on the adhesion potential and physicochemical cell surface of probiotics is still unclear. We examined the postbiotic influence produced by Escherichia coli Nissle 1917 in functional labneh on cell surface properties (auto-aggregation, hydrophobicity, and co-aggregation) and the adhesion capacities of three probiotic strains. The most commonly detected effects of probiotics, particularly L-syn(-7), were an increase in auto-aggregation, hydrophobicity, co-aggregation, and adhesion ability of the tested strains. Lactobacillus rhamnosus with Lsyn-7 (59%) presented the highest hydrophobicity, whereas the least adhesion to xylene was detected in L. rhamnosus with LHM. Lactobacillus casei with L-syn(-7) showed the highest auto-aggregation after 24 h (60.55%). Moreover, it also has a strong adhesion to Caco-2 cells and effectively prevents the binding of Salmonella Typhimurium to Caco-2 cells. Lactobacillus plantarum with Lsyn-7 presented the strongest co-aggregation with Staphylococcus aureus (85.1%), S. typhimurium (85. 02%) and Listeria monocytogenes (77.4%). The adherence potential of tested probiotic strains was highly correlated with auto-aggregation, hydrophobicity, co-aggregation, and competitive inhibition of L. monocytogenes and S. typhimurium. The findings suggest that L-syn(-7) can be a candidate to promote the adhesion potential of selected probiotic strains. For the reason that the application of probiotic strains has been more interested in their positive influences in the gastrointestinal tract, it is essential to use some functional compounds, such as postbiotics, to improve adhesion abilities and cell surface properties in terms of bacterial binding.