Some Contributions to the Study of Oenological Lactic Acid Bacteria through Their Interaction with Polyphenols

Probiotic features and the ability of two oenological lactic acid bacteria strains (Pediococcus pentosaceus CIAL‐86 and Lactobacillus plantarum CIAL‐121) and a reference probiotic strain (Lactobacillus plantarum CLC 17) to metabolize wine polyphenols are examined. After summarizing previous results regarding their resistance to lysozyme, gastric juice and bile salts, the three strains were assessed for their ability to release phenolic metabolites after their incubation with a wine phenolic extract. Neither of the two bacteria were able to metabolize wine polyphenols, at least in the conditions used in this study, although a certain stimulatory effect on bacterial growth was observed in the presence of a wine‐derived phenolic metabolite (i.e., 3,4‐dihydroxyphenylacetic acid) and a wine phenolic compound (i.e., (+) ‐catechin). Bacteria cell‐free supernatants from the three strains delayed and inhibited almost completely the growth of the pathogen E. coli CIAL‐153, probably due to the presence of organic acids derived from the bacterial metabolism of carbohydrates. Lastly, the three strains showed a high percentage of adhesion to intestinal cells, and pre‐incubation of Caco‐2 cells with bacteria strains prior to the addition of E. coli CIAL‐153 produced a notable inhibition of the adhesion of E. coli to the intestinal cells.