Castanea henryi-resistant starch prepared with autoclave-assisted pullulanase treatment attenuated high-fat diet-induced obesity by regulating gut microbiota and metabolism.

The high glycemic index of Castanea henryi has significantly hampered its utilization for new product development. In this study, Castanea henryi starch was processed by autoclave-assisted pullulanase treatment (AAPT) to prepare resistant starch (RS). The structural property, crystal structure and thermal stability of the modified starch were investigated. The anti-obesity effects of the Castanea henryi-resistant starch (CHRS) were evaluated in animal model, and the underlying mechanisms were explored via gut microbiota and metabolome analysis. Results indicated that AAPT significantly increased the type 3 CHRS content and reduced glycemic index due to the ordered structure charactered by B + V-type crystallization. CHRS lowered the high-fat diet (HFD)-induced obesity by reducing fat accumulation and inflammation, enhancing antioxidant activities and protecting intestinal barrier. Microbiome analysis indicated that CHRS reconstructed the HFD-induced intestinal microbiota disorder by decreasing the Firmicutes-to-Bacteroides ratio and increasing the abundances of microbes, including Muribaculaceae, Clostridia_UCG-014 and Lactobacillus. Metabolomics analysis manifested that CHRS induced an improved metabolic profile mainly involved in the biosynthesis of secondary metabolites and glycerophospholipid metabolism. The correlation analysis further provided support for the positive roles of the CHRS-induced alterations in intestinal microbiota and metabolites on obesity. Our study provides an alternative strategy for developing Castanea henryi derived functional foods.