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

•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.