Evaluating the potential prebiotic effects of umbu-cajá (Spondias spp.) fruit processing by-product flour on the human intestinal microbiota

This study evaluated the potential prebiotic properties of umbu-cajá ( Spondias spp.) fruit processing by-product flour (UCF) on the human intestinal microbiota by monitoring the relative abundance of specific intestinal bacterial populations, microbial metabolic behavior, and antioxidant activity during 48 h of in vitro colonic fermentation using fecal inoculum donated from healthy adult individuals. UCF had a high insoluble fiber content and flavonols, especially quercetin-3- O -glucoside, as the most prevalent phenolic compounds, besides showing antioxidant activity. Medium with UCF increased the relative abundance of Lactobacillus spp./ Enterococcus spp., Bifidobacterium spp., and Clostridium histolyticum during the colonic fermentation and decreased the relative abundance of Bacteroides spp./ Prevotella spp. and Eubacterium rectale/Clostridium coccoides . Medium with UCF maintained a higher relative abundance of Ruminococcus albus/R. flavefaciens than negative control during the colonic fermentation. UCF stimulated intense metabolic activity of the intestinal microbiota during the colonic fermentation, evidenced by decreased pH values, sugar consumption, and production of several metabolites linked to host health promotion, concomitant with high antioxidant activity. The results characterize UCF as a candidate for prebiotic use and a novel value-added circular ingredient to functionalize foods and nutraceuticals. • Umbu-cajá by-product flour (UCF) impacted colonic bacterial populations. • UCF affected the production of metabolites during colonic fermentation. • UCF enhanced the antioxidant activity in colonic fermentation media. • UCF is a candidate for a novel circular prebiotic ingredient.