In vitro colonic fermentation profiles and microbial responses of propionylated high-amylose maize starch by individual Bacteroides-dominated enterotype inocula

The concept of enterotype has been proposed to differentiate the gut microbiota between individual humans, and different dominant bacteria utilize fiber substrates with different fermentation properties and microbial changes. In this study, we made propionylated high-amylose maize starch and investigated both in vitro fecal fermentation properties and microbial responses by individual Bacteroides-dominated enterotype inocula. Propionyl group substitution of HAMS did not significantly change gas production profiles, suggesting that the gas production during fermentation is independent of propionylation. The final concentration of released propionate significantly increased (10.26-12.60 mM) as a function of propionylation degree, suggesting that the introduced propionyl groups can increase the concentration of short-chain fatty acids (SCFA) during colonic fermentation. At the genus level, Bacteroides was obviously promoted for all donors with the final abundance in the range of 0.1-0.24, indicating that propionylated high-amylose maize starch changed the structure and abundance of microbiota compared to unmodified starch. Besides, the non-metric dimensional scoring (NMDS) plots showed that those changes were related to the initial microbiota composition. The results may offer useful information for the design of personalized food products and relevant therapies at least within Bacteroides-dominated enterotype.