Optimal preparation process and in vitro digestion characteristics of konjac glucomannan and kudzu root resistant starch composite gel

This study explored konjac composite gel with hypoglycemic properties. Kudzu root resistant starch (KRS) was added to enhance the gel's characteristics. Single-factor and orthogonal experiments optimized preparation conditions, revealing an optimal process: konjac semolina: water is 1:40 (w/v), 90 °C, KRS 2.00 g, alkali 18 %, stirring for 45 min. The water-holding capacity of the konjac composite gel prepared by this process reached 90.22 %, which is 15.81 % higher than that of pure konjac gel (74.41 %). Characterization of the composite gel by SEM, texture profile analysis, and sensory evaluation confirmed its enhanced quality. The reinforced network structure fundamentally improved the composite gel's textural properties. Its hardness, springiness, and chewiness reached 2.4, 1.1, and 1.2 times those of native KGM, respectively, resulting in an optimized mouthfeel. In vitro gastrointestinal digestion simulations were performed to assess the digestibility of the composite gels. The starch hydrolysis rates of the konjac composite gel were 1.338 % and 9.688 %. The composite gel exhibited significant α -amylase and α -glucosidase inhibitory activities (IR = 55.84 % and 48.78 %), indicating its potential as a functional food for glycemic control.