Polyphenols non-covalently bound to artificial plant cell walls are readily accessible to fecal microbiota and transiently alter fermentation activity

Abstract

This study aimed to elucidate three-way interactions among dietary fiber, polyphenols (PPs), and the gut microbiota at physiologically relevant concentrations. A three-component bacterial cellulose analogue of the apple cell wall (aACW) soaked in a PP extract from apples (aACW + PP) was produced and gut microbial responses were tested using in vitro fecal microbiota batch fermentations of five donors. Soaking left ∼17 % of PPs bound to aACWs, with flavonols being the most retained. Several flavonoids were detected early during aACW + PPs in vitro fecal fermentation and were rapidly metabolized with differences between individual fecal microbiota. aACW-bound PP increased fermentation activity, as indicated by higher acetic acid and lower formic acid levels after 5 h of fermentation. Beta-diversity analysis identified donor individuality as a stronger determinant of microbiota composition than treatment. Baseline interindividual microbiota composition emerged as the dominant factor shaping both PP metabolism and microbial community trajectories under the tested, physiologically relevant concentrations.

Keywords: Dietary fiber; Fecal microbiome; Food waste; Hydrocolloids; In vitro colonic fermentation.