GUT MICROBIOTA MODULATION AFTER SIMULATED DIGESTION OF YOGURT CONTAINING RED GRAPE POMACE POLYPHENOLS

LINGUA M; LUCINI MAS, A; MATTALONI, M; SALVUCCI, E.; BLAJMAN, J; PAEZ, ROXANA; DANIEL A. WUNDERLIN; BARONI M.V.

LOS COCOS

Congreso; XVII Congreso Argentino de Microbiología General; 2022

SOCIEDAD ARGENTINA DE MICROBIOLOGIA

Consumption of dietary polyphenols has been linked with reduced risk of cardiovascular and neurodegenerative diseases and cancer, due to their antioxidant power. Additionally, nowadays these molecules are reported by modular the composition and activity of the microbial populations in the colon, affecting positively the human health. Red grape pomace is an important and abundant solid waste generated after the red winemaking process that still retains large amounts of these beneficial polyphenols for health. The objective of this study was to carry out in vitro gastric digestion and colonic fermentation of yogurt made with microencapsulated polyphenols from red grape pomace and to observe the effect on different bacteria groups of the gut microbiota and on the polyphenol content and antioxidant capacity. Yogurts with polyphenols were prepared by addition of 10% w/w of microcapsules of red grapes pomace polyphenols obtained by spray drying of phenolic extract using 30% w/v of maltodextrin: skimmed milk powder (50:50) as an encapsulating agent. Yogurts control, without polyphenols, were prepared by adding 10% w/w of encapsulating agent microcapsules only. The digestion process was simulated in four steps, 1- digestion in the mouth, 2- digestion in the stomach, 3- digestion/ absorption in the small intestine, and 4- colonic fermentation (using Balb c mice fecal) and adsorption in the large intestine. Enterobacteriaceae, lactic acid bacteria, total anaerobes, and presumptive bifidobacteria were counted before and after colonic fermentation using selective and partially selective mediums (Eosin methylene blue agar (EMB), de Man, Rogosa, and Sharpe (MRS), reinforced clostridial agar (RCA), and MRS supplemented with 5% v/v propionic acid, respectively). Total polyphenols, by Folin-Ciocalteu, and antioxidant capacity, by FRAP and ABTS assays, were measured during digestion. Results showed that after fermentation yogurt with polyphenols promoted a higher growth for presumptive bifidobacteria compared with yogurt control. Considering total anaerobes, the presence of polyphenols in yogurt helped to reduce the growth of this group population with respect to yogurt control. The total polyphenols and antioxidant capacity were modified after digestion and colonic fermentation remaining higher than the control formulation. Results suggest that the gut microbiota during the colonic fermentation modified the polyphenol content, with a consequent change in antioxidant capacity, of yogurt with polyphenols from red grape pomace at the same time that moduled positively its composition.