<i>In vitro</i> human colonic fermentation of indigestible fraction isolated from lunch menus: impact on the gut metabolites and antioxidant capacity

<p>The indigestible fraction (IF) isolated from three lunch menus: Modified Mexican Lunch (MM-L), Traditional Mexican Lunch (TM-L) and Alternative Mexican Lunch (AM-L), was studied in terms of antioxidant capacity (AOX) and metabolites produced through fermentation by human intestinal microbiota. IFs were isolated after withstanding <i>in vitro</i> gastrointestinal digestion and total soluble polyphenols (TSP), condensed tannins (CT), hydrolysable polyphenols (HP) and AOX (DPPH, FRAP) were evaluated. AOX, pH and bacterial metabolites profile changes were also monitored during <i>in vitro</i> colonic fermentation. Lunch menus showed differences in IF, TSP, CT and FRAP values (<i>p</i><.05). TM-L had the highest TSP and CT contents (0.84 and 1.89 g/100 g DW, respectively). Changes in pH and AOX during fermentation were time-dependent and substrate-dependent (<i>p</i><.05). Butyric acid production was not significantly modified by the IFs (<i>p</i>>.05). Fifty-seven microbiota-produced volatile compounds were detected by SPME-GC–MS. This study shows the potential effects of food habits on bacterial metabolite production.</p>