Coconut (Cocos nucifera L.) and Carob (Ceratonia siliqua L.) Flours Dietary Fibers Differentially Impact Fecal Microbiota Composition and Metabolic Outputs In Vitro

Abstract

Alternative flours can reveal beneficial health effects. The aim of this study was to evaluate and compare the effects of dietary fibers (DFs) of coconut and carob flours on colonic microbiota compositions and function. Coconut flour DFs were found to be dominated by mannose-containing polysaccharides by gas chromatography (GC)/MS and spectrophotometer, whereas glucose and uronic acid were the main monosaccharide moieties in carob flour DFs. In vitro fecal fermentation analysis revealed that coconut flour DFs result in the generation of microbial butyrate as much as inulin does, which is known to be a butyrogenic prebiotic, but at a slower rate. Supportingly, coconut flour DFs promoted butyrate-producing bacteria including Roseburia and Coprococcus, whereas carob flour DFs stimulated Prevotella-related OTUs. In addition, higher microbial diversity was achieved at the end of the fermentation of coconut flour DFs by the fecal microbiota. This study clearly shows that alternative flours have distinct functionalities in terms of colonic microbiota composition and function, and coconut flour could be used as an alternative flour for the development of functional food products targeting colonic health.