Impact of a probiotic soy beverage supplemented with acerola by-product on gut microbiota from lean and obese subjects assessed in a dynamic in vitro model of the human colon (TIM-2)

The aim of this study was to evaluate the effects of soy-based beverages manufactured with water-soluble soy extract, containing probiotic strains (Lactobacillus acidophilus LA-5 and Bifidobacterium longum BB-46) and acerola by-product (ABP) on the modulation of microbiotas from lean and obese individuals. The TIM-2 system, a validated dynamic in vitro model that mimics the conditions of the human proximal colon, was used. Four fermented soy beverages (FS) [“placebo” (FS-Pla), probiotic (FS-Pro), prebiotic (FS-Pre), and synbiotic (FS-Syn)] were submitted to an in vitro digestion, followed by introduction in the TIM-2 system. Short- and branched-chain fatty acids (SCFA and BCFA) and microbiota composition were determined. After the simulated colonic fermentation in the presence of the four different FS formulations, acetic and lactic acid production was higher than the control treatment for microbiota from lean individuals (MLI). Additionally, SCFA production by the MLI was higher than for the microbiota from obese individuals (MOI). Bifidobacterium spp. and Lactobacillus spp. populations increased during simulated colonic fermentation in the presence of FS-Syn in MLI and MOI. The results also showed that FS formulations changed the composition of the MOI, resulting in a profile more similar to MLI. The changes in the composition and the increase in SCFA production observed for the MLI and MOI during these in vitro fermentations suggest a potential modulation effect of these microbiotas by the consumption of functional FS.