Evaluation studies on effects of quercetin with different concentrations on the physicochemical properties and in vitro digestibility of Tartary buckwheat starch

The effects of polyphenols on the physicochemical properties and in vitro digestibility of Tartary buckwheat starch (TBS) remain scarce. In this study, the rheological, thermal properties, and in vitro digestibility of pregelatinized TBS (pre-TBS) with quercetin complexation at various concentrations were characterized. It was found that quercetin complexation increased the shearing resistance and viscosity of pre-TBS. Both SEM and TGA results revealed a more compact and stable structure of starch-quercetin complex in comparison to pre-TBS. The non-inclusive complex with higher crystallinity was formed through hydrogen bonds, which showed by XRD and FT-IR results. Additionally, complexes exhibited the lower digestion rate and digestion velocity constant, and the resistant starch content of complex (with 10% quercetin addition) was the highest. Therefore, quercetin complexation could improve the thermal and rheological properties, and decrease in vitro digestibility of pre-TBS, which could provide a theoretical basis for functional food development.