The K+ and Mg2+ decreased the adsorption of soy hull polysaccharides on glycocholic acid in vitro

Abstract This study aimed to explore the effect of ion on the interaction between soy hull polysaccharides (SHP) and glycocholic acid (GCA). The determination of bile acids (BAs) binding rate, FT-IR, and zeta potential revealed that the binding rate of SHP to GCA (fell about 14 %), hydrogen bond peak area (fell about 149), and zeta potential (fell about 13 %) showed a sharp downward trend after K+ and Mg2+ treatment. However, the apparent viscosity increased and the chain structure became closer, as detected by shear rheology and AFM analysis. The root mean square deviation, radius of gyration, and root mean square fluctuation levels were estimated through molecular dynamic simulations, revealing that adding mixed ions decreased the stability of the SHP–GCA complex at 50 ns. Therefore, it was meaningful to study the effect of ion species in the intestinal environment on the binding of dietary fibers to BAs. The findings might guide the selection of other food types during polysaccharide intake.