Complexation of starch and konjac glucomannan during screw extrusion exhibits obesity-reducing effects by modulating the intestinal microbiome and its metabolites

Abstract

Dietary interventions have been shown to improve gut health by altering the gut flora, preventing obesity, and mitigating inflammatory disorders. This study investigated the benefits of a rice starch–konjac glucomannan (ERS–KGM) complex, produced via screw extrusion, for gut health and obesity prevention. Analyzed through in vitro starch digestion, scanning electron microscopy, and structural analysis, the ERS–KGM complex exhibited a notable increase in resistant starch content due to its well-ordered structure. When administered to mice on a high-fat diet for 8 weeks, the ERS–KGM complex significantly reduced body weight, white adipose tissue mass, adipocyte size, and food intake while increasing water consumption. It also improved glucose metabolism, insulin sensitivity, and lipid profiles by lowering serum triglycerides and total glycerol content. Enhanced metabolic biomarkers and enzyme activities were observed, specifically involving glycerophospholipid metabolism. It decreased the activities of aldehyde dehydrogenase, lactate dehydrogenase, and amino acid transaminase while increasing antioxidant enzymes like glutathione peroxidase and superoxide dismutase. Additionally, it elevated glycogen and positively altered gut microbiota by enriching Firmicutes, Desulfobacterota, and Bifidobacterium. This change enhanced the ability to degrade specific compounds and elevated the concentrations of short-chain fatty acids in feces. These findings suggest that the ERS–KGM complex could serve as a dietary supplement for obesity prevention.