In this study, the interaction between quercetin and Fagopyrum tataricum starch, as well as the mechanism by which it increases the RS content, was analyzed. The results showed: (1) at 5% addition, RS content reached 60.38%. (2) Quercetin penetrated starch granules and blocked pore structures, reducing the accessible surface area and hindering amylase hydrolysis: the first mechanism for RS increase. (3) The internal quercetin formed stable complexes with starch molecules (90 kJ/mol binding energy, 7H-bonds), reconstructing the hydrogen bonding network, altering molecular arrangement, and modifying gelatinization properties. Due to steric hindrance, the starch molecule complexed with quercetin failed to fully insert into the α-amylase active groove, limiting contact with the catalytic triad: the second mechanism for RS increase. (4) External quercetin molecules bound stably within the α-amylase active groove (49 kJ/mol binding energy, 5H-bonds), inhibiting enzyme activity: the third mechanism for RS increase.
Li et al. (Wed,) studied this question.