Investigating the effects of conventional and unconventional edible parts of red beet (Beta vulgaris L.) on target bacterial groups and metabolic activity of human colonic microbiota to produce novel and sustainable prebiotic ingredients

[Display omitted] •The impacts of distinct red bet edible parts on human colonic microbiota were investigated.•Red beet roots and stem/leaves altered the abundance of distinct colonic bacterial groups.•Red beet roots (RBR) and stem/leaves (RBSL) had positive prebiotic indexes.•RBR and RBSL affected the production of metabolites during colonic fermentation.•RBR and RBSL increased the antioxidant capacity in colonic fermentation media. This study investigated the effects of freeze-dried red beet root (FDBR) and freeze-dried red beet stem and leaves (FDBSL) on target bacterial groups and metabolic activity of human colonic microbiota in vitro. The capability of FDBR and FDBSL to cause alterations in the relative abundance of different selected bacterial groups found as part of human intestinal microbiota, as well as in pH values, sugar, short-chain fatty acid, phenolic compounds, and antioxidant capacity were evaluated during 48 h of in vitro colonic fermentation. FDBR and FDBSL were submitted to simulated gastrointestinal digestion and freeze-dried prior to use in colonic fermentation. FDBR and FDBSL overall increased the relative abundance of Lactobacillus spp./Enterococcus spp. (3.64–7.60%) and Bifidobacterium spp. (2.76–5.78%) and decreased the relative abundance of Bacteroides spp./Prevotella spp. (9.56–4.18%), Clostridium histolyticum (1.62–1.15%), and Eubacterium rectale/Clostridium coccoides (2.33–1.49%) during 48 h of colonic fermentation. FDBR and FDBSL had high positive prebiotic indexes (>3.61) during colonic fermentation, indicating selective stimulatory effects on beneficial intestinal bacterial groups. FDBR and FDBSL increased the metabolic activity of human colonic microbiota, evidenced by decreased pH, sugar consumption, short-chain fatty acid production, alterations in phenolic compound contents, and maintenance of high antioxidant capacity during colonic fermentation. The results indicate that FDBR and FDBSL could induce beneficial alterations in the composition and metabolic activity of human intestinal microbiota, as well as that conventional and unconventional red beet edible parts are candidates to use as novel and sustainable prebiotic ingredients.