Mechanistic study of quercetin on Fagopyrum Tataricum resistant starch.

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.