Preparation, physicochemical properties, and specific properties of the gut mycobiota associated with the anti-hepatic steatosis benefit in mice of microcrystalline propionylated starch.

Abstract

Propionate-acylated resistant starch has garnered attention for its unique ability to infuse specific SCFAs in the distal colon. Here, MPS with an elevated level of resistant starch was first prepared. Then, the effects of MPS on hepatic steatosis and the gut mycobiome were investigated in mice. Specifically, microcrystalline pea starch, serving as the starting material, underwent esterification with propionic anhydride to produce MPS. With the supplementation of propionic anhydride, the novel characteristic peaks were observed and the relative crystallinity of MPS was increased, according to FT-IR and XRD analysis, respectively. Moreover, the resistant starch content increased from 64.38 % in MPS1 (DS 0.0505) to 93.26 % in MPS5 (DS 0.2511). Additionally, MPS5 supplementation decreased hepatic steatosis and intestinal dysfunction in HFD-fed mice and increased the propionic acid in the faeces of HFD-fed mice, indicating that the introduced propionyl groups were successfully delivered to the colon and improved hepatic lipid metabolism. Fungal-specific internal transcribed spacer amplicon sequencing revealed that MPS5 modified the gut mycobiome composition in HFD-fed mice, with increases in Penicillium and Colletotrichum, which are linked to the anti-hepatic steatosis benefit. Overall, the present research provides a reference for the design of resistant starch that can produce high levels of propionate, modulate the gut mycobiome, and produce anti-hepatic steatosis benefits.