Study on the mechanism of starch granule-associated proteins in fermented barley on starch digestibility.

This study aimed to elucidate how fermentation regulates the composition of starch granule-associated proteins (SGAPs) and starch granule channel proteins (SGCPs), and their relationship with starch digestibility. Qualitative proteomic analysis revealed differences in the detectable protein profiles, with F2E8J4 and P07596 detected only in F-SGAPs under the present analytical conditions. Mechanistic studies using fluorescein-labeled enzyme technology, interaction force analysis, and enzymatic reaction kinetics revealed that SGAPs impede starch-enzyme binding. Although fermentation weakened electrostatic interactions between SGAPs and starch, it optimized starch ordered structure and increased the apparent inhibitory effect on α-amylase, thereby increasing the resistance of starch to digestion. These findings indicate that fermentation reduces starch digestibility by modifying protein composition and optimizing starch structure.