Konjac glucomannan-embedded corn starch-derived type 1 resistant starch: Physicochemical properties, in vitro digestibility and fermentation characteristics, and in vivo glucose response in mice

Type 1 resistant starch (RS1) was prepared by high-pressure homogenization of corn starch (CS) embedded with 0.1%, 0.3%, 0.5%, and 0.7% konjac glucomannan (KGM), followed by heat-moisture treatment (HMT) at 30% moisture content and 110 °C for 6 h. After embedding KGM and applying HMT, the gelatinization temperature of CS increased by 8.09 °C, and the resistant starch content of cooked CS increased from 8.46% to 28.05%. The addition of KGM enhanced the adhesiveness and hardness of CS while reducing its elasticity and chewiness. Rheological analysis revealed that KGM addition increased both the storage and loss moduli of CS, and the crystallinity of KGM-embedded CS decreased to 18.58%. Moreover, short-chain fatty acid production and the abundance of beneficial bacteria, including Lachnospiraceae, Prevotellaceae, Anaerostipes, and Weissella, were higher in the RS1 group compared to the high-amylose maize starch and fructooligosaccharide groups. In the in vivo digestibility experiment, the peak blood glucose level in the RS1 group (7.08 mmol/L) was significantly lower than that in the CS group (8.57 mmol/L). These findings highlight the potential of KGM-embedded CS-derived RS1 in improving postprandial blood glucose levels in individuals with type 2 diabetes and obesity.