Impact of konjac glucomannan on starch digestibility: An in - depth exploration of properties and dynamics

The molecular weight (Mw) of polysaccharides significantly modulates both the kinetics and the extent of enzymatic starch digestion. The regulatory mechanism of konjac glucomannan (KGM) with different Mw was explored on starch digestion in this investigation. Results displayed that KGM could effectively diminished the starch hydrolysis rate and elevated resistant starch (RS) content in a pronounced Mw-dependent manner, while the supplementation of samples with the higher Mw (Mw of 2406 KDa) facilitated the maximal increase of 11.82 % in RS content. The inhibition of KGM on α-glucosidase demonstrated superior efficacy to that of α-amylase, with an inhibition rate of up to 62.5 %. Molecular docking simulations further indicated that KGM occupied the catalytic pockets of both α-amylase and α-glucosidase, establishing stable hydrogen-bond networks. The fluorescence quenching mechanism revealed that smaller Mw KGM induced a static quenching effect on both enzymes, while larger Mw KGM exhibited a dynamic quenching effect. The enzyme exhibited elevated β-sheet and α-helix contents accompanied by a concomitant decline in β-turn structures as the Mw of KGM increased, with reductions of 8.72 % and 4.10 %, respectively. In conclusion, this study provided a foundation for developing precise glycemic control foods and optimizing food functional properties, which could promote healthy diets and help prevent and control chronic diseases.