Fermentation of dietary fibers modified by an enzymatic‐ultrasonic treatment and evaluation of their impact on gut microbiota in mice

Abstract

Dietary fiber (DF) from sisal waste and Moringa oleifera stem were modified using a successive enzymatic-ultrasonic (E-U) treatment to produce modified DF products (MDFs), with reduced ratio of insoluble DF (IDF) and soluble DF (SDF) and decreased particle size. The water-holding capacity, swelling capacity, and oil-holding capacity of the MDFs were elevated upon E-U treatment. MDF-S (MDF from sisal waste) and MDF-M (MDF from M. oleifera stem) were fermented to produce short-chain fatty acids (SCFAs) by gut bacteria in mice, with total SCFA content of 3.81 μmol/g and 3.34 μmol/g, respectively, when added in basal feed at 10% (wt/wt). Metagenomic analyses demonstrated that MDFs tended to increase the Bacteroidetes/Firmicutes ratio, and significantly increased the relative abundance of Bacteroides, norank_f__Bacteroidales_S24-7_group, norank_f__Erysipelotrichaceae, Ruminococcus_1, and Akkermansia at genus level. These findings suggest that MDF supplementation in diet could favorably modulate gut microbiome in mice. Novelty impact statement We proposed a DF modification strategy to improve its role in intestinal flora modulation. Our results suggest that successive enzymatic and ultrasonic treatment effectively reduced the IDF/SDF ratio of DF. Supplement of the modified DF could alter the intestinal flora of mice to a high Bacteroidetes/Firmicutes ratio and elevate the relative abundance of several beneficial microbiota.