The Digestive Residues of Maize Starch-Caffeic Acid Complexes Significantly Change the Metabolites and Microbiota Composition During in Vitro Colon Fermentation

Abstract

To investigate the effect of digestive residues of maize starch–caffeic complexes on the composition of human metabolites and gut microbiota, maize starch was extruded with caffeic acid, and subjected to in vitro gastrointestinal digestion. Then, the undigested parts were fermented with human faecal microbiota in vitro, and the morphology, short-chain fatty acids composition, microbiota communities and structural characteristics of the fermented residues were investigated. The results indicated that the amorphous area of the residues is preferentially utilized by gut microbiota and then the crystalline area. The acetate concentration in extruded maize residues with or without caffeic acid residues increased to 19.19 ± 0.40 and 23.10 ± 0.92 mmoL/L, respectively, after 24 h of fermentation. Microbiota analysis indicated that the digestive residue of maize starch-caffeic acid complexes promoted the growth of potentially beneficial microbiota, especially Bifidobacterium and Lactococcus genus. In general, extruded maize starch with caffeic acid might be a potential functional food substance for gut health.

Keywords: Extrusion, maize starch-caffeic acid complex, in vitro fermentation, short-chain fatty acids, gut microbiota