In Vitro Probiotic-Related and Functional Characterization of Yeasts Isolated from Traditional Turkish Pickles

Background: Traditional fermented foods contain diverse yeasts with potentially relevant technological and probiotic-related traits. This study examined yeasts isolated from five types of traditional Turkish pickles (mushroom, cucumber, cabbage, bean, and taflan) to assess their in vitro functional characteristics. Methods: Twenty-eight yeast isolates were identified by MALDI-TOF MS and ITS-region sequencing and evaluated for simulated gastrointestinal survival, biofilm formation, cell-surface hydrophobicity, auto-aggregation, co-aggregation with foodborne bacteria, extracellular enzyme activities, antimicrobial activity, and DPPH radical-scavenging capacity. Results: The isolates included Pichia kudriavzevii, Pichia fermentans, Saccharomyces cerevisiae, and other yeast species. Twenty-one isolates (75%) exceeded 50% survival under simulated gastric conditions, whereas four (approximately 14%) exceeded 30% survival under subsequent pancreatic conditions. Co-aggregation with Escherichia coli ATCC 25922 reached 95.7%; inhibition of this bacterium was observed for 27 isolates (96.4%). Intact-cell DPPH radical-scavenging activity reached 36.25%. Conclusions: Pickle-associated yeasts displayed diverse strain-dependent in vitro functional traits. Further strain-specific safety assessment and testing in food matrices are necessary; these findings do not establish probiotic efficacy or suitability for consumption.