Gut metabolites associated with pH and antioxidant capacity during in vitro colonic fermentation of Mexican corn products

Background and objectives: Food is the major factor driving the metabolism of the gut microbiota. In Mexico, nixtamalized corn products are widely consumed. Changes in antioxidant capacity (AOX) in 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and Ferric ion reducing antioxidant power (FRAP), pH values, short-chain fatty acid concentration, and relative metabolite production during in vitro colonic fermentation of indigestible fractions (IF) isolated from Istmo Totopos (ITs), baked corn tortillas (BCTs), and traditional corn tortillas (TCTs) were analyzed. Findings: The consumption of one piece (10 g) of any corn product may potentially maintain appreciable colonic antioxidant status (above 60 mmol TE) until 48 hr of fermentation. A portion of 10 g of corn products produces similar concentrations of acetic (3,050.43–4,181.47 mM), propionic (1,904.78–2,975.18 mM), and butyric acid (1,458.14–2,873.47 mM) at 12 hr of fermentation. Forty-six volatile compounds were also detected by solid-phase microextraction–gas chromatography–mass spectrometry (SPME–GC–MS), and six principal components were identified. Positive correlations were found between DPPH, acetic acid, propionic acid, and butyric acid. Conclusions: Our results suggest the colonic fermentation potential to increase bioactive compounds and antioxidant activity hence suggesting improved gut health. Additional studies are required to evaluate their in vivo effects. Significance and novelty: The study of traditional corn products will facilitate a better understanding of the potential health-promoting impact of the interactions between indigestible components of the Mexican diet and the gut metabolites.