Modulation of gut microbiota by rice starch enzymatically modified using amylosucrase from Deinococcus geothermalis

Amylosucrase can increase the amount of resistant starch (RS) in starch by transferring glucose from sucrose to amylopectin. Here, rice starch was modified using amylosucrase from Deinococcus geothermalis (DgAS). DgAS-modified rice starch (DMRS) increased the side-chain length of amylopectin and appeared in the form of B-type crystals. In vitro digestion analyses revealed that DMRS had a higher RS contents and lower digestion rate than native rice starch. When high-fat diet (HFD)-induced C57BL/6 mice were orally administered DMRS, body weight and white fat tissues of DMRS-fed HFD mice were not significantly different. However, serum leptin and glucose levels were significantly decreased and serum glucagon like peptide-1was increased in these mice. The cecal microbiome in DMRS-fed HFD mice was identified to investigate the role of DMRS in gut microbiota regulation. DMRS supplementation increased the relative abundance of Bacteroides , Faecalibaculum , and Ruminococcus in mouse gut microbiota.