Integrated metagenomic and metabolomic profiling in an in vitro colonic fermentation study to assess the impacts of conventional, unconventional, and whole edible beet (Beta vulgaris L.) parts on the composition and metabolic responses of the intestinal microbiota of hypertensive individuals

Beet (Beta vulgaris L.) has been widely studied as a functional food, particularly for its bioactive compounds. This study evaluated the physicochemical characteristics, nutritional composition, antioxidant capacity, and the impacts of freeze-dried beet root (FDBR), freeze-dried beet stems and leaves (FDBSL), and freeze-dried whole beet (FDWB) on the composition and metabolic responses of the intestinal microbiota of hypertensive individuals. FDBR, FDBSL, and FDWB had high nutritional value. FDWB had the highest protein content (10.6/100 g), while FDBSL had the highest total dietary fiber content (46.6/100 g). Twenty-eight phenolic compounds were identified, and the antioxidant capacity reached up to 60.6 µmol Trolox/g in FDBR. 16S rRNA amplicon sequencing analysis demonstrated that colonic fermentation of FDBR, FDBSL, and FDWB with fecal inoculum from hypertensive individuals decreased the Firmicutes/Bacteroidetes ratio, decreased or maintained the bacterial diversity, increased the relative abundance of Bifidobacteriaceae, Lactobacillaceae, and Enterobacteriaceae, and decreased Lachnospiraceae, Oscillospiraceae, and Peptostreptococcaceae. Colonic fermentation of FDBR mainly increased the abundance of Bifidobacterium (1.18-7.63%), while FDBSL increased the abundance of Phocaeicola. FDBR, FDBSL, and FDWB decreased the pH values (6.74-5.09) and altered the metabolic profile during colonic fermentation by consuming sugar and producing several metabolites associated with health-promoting properties, while maintaining antioxidant capacity. FDBR, FDBSL, and FDWB may be circular resources with beneficial effects on the composition and metabolic responses of the intestinal microbiota in hypertensive individuals and could be exploited as dietary adjuvant strategies in the management of arterial hypertension.