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The survival of bacterial strains isolated from tejuino was evaluated in the human gastrointestinal model (ARIS) using saline solution and simulated food as matrices. Antagonistic activity towards pathogenic bacteria, short-chain fatty acids production and adhesion to HT-29 cells were also studied. Leuconostoc citreum CIATEJ BI–49.1 , Weissella cibaria CIATEJ BI–48.1 , Chryseobacterium bovis CIATEJ BI–55.1 and Bacillus safensis CIATEJ BI–75.1 were selected and inoculated in ARIS model. B. safensis and C. bovis were unable to survive the simulated human gastrointestinal tract conditions. Leu. citreum seemed to be more resistant to gastrointestinal conditions than W. cibaria , recovering 7–8 log CFU/mL. In the antagonistic assay, Leu. citreum showed the highest (p S. aureus and S. Typhimurium strains, while W. cibaria had the highest (p L. monocytogenes . In regards of short chain fatty acids production, Leu. citreum showed highest (p W. cibaria (approximately 0.5%). Leu. citreum could be a potential probiotic strain due to its tolerance to gastrointestinal conditions, antagonistic activity towards foodborne pathogens, short-chain fatty acids production and adhesion to HT-29 cells.

In the fermentation process of distilled spirits from Agave sugars, saponins inhibit the growth of yeasts during this procedure. This type of compound is present in the must, and the mechanisms of the cell growth inhibition are poorly understood. The fundamental objective of this work was to study the effect of saponins on the cell walls of the fermentative yeasts Saccharomyces cerevisiae and Kluyveromyces marxianus. This study was performed in batch and continuous cultures, adding pulses of saponins extracted from the leaves of Agave durangensis and Agave salmiana ssp. crassispina. The saponin extract from A. durangensis exhibited a stronger growth inhibitory effect in both yeast strains than A. salmiana saponin extract due to the structure of the saponins. However, in K. marxianus growth recovery was observed, because these strain showed saponinase activity that performed the saponin hydrolysis. Finally, microscopic observations confirmed the changes in the wall cell of S. cerevisiae and K. marxianus .