Interaction with taxifolin reduces the digestibility of corn starch in vitro and in vivo

Reducing the hydrolysis of starch in the gastrointestinal tract can improve postprandial hyperglycemia, which is beneficial for diabetes. The blends of corn starch with taxifolin (CS-Tax) were prepared with different taxifolin proportion. Iodine binding test showed that taxifolin can occupy the helix of starch, and the affinity is stronger than that of iodine. FTIR and XRD characterization revealed secondary interaction between taxifolin and starch in the blends, and the crystallization of taxifolin was suppressed. Taxifolin decreased the gelatinization temperature and enthalpy for starch. Scanning electron microscopy showed that the morphology of the blends was the same as starch granules. In vitro digestion experiment showed that taxifolin could slow down starch hydrolysis. Compared with native starch, the content of rapidly digestible starch in CS-10%Tax decreased from 56.35 to 49.20%, while the content of resistant starch increased from 17.62 to 29.61%. The comparison in vivo showed that after intragastric administration of CS-10%Tax in rats, the increase of blood glucose slowed down and the maximum decreased from 7.1 to 6.2 mM. Hence, taxifolin is prospective in preparing low glycemic index starchy foods and deserves further study.