Co-gelatinization with rutin nanoparticles for regulating rice starch digestibility

Polyphenolic compounds demonstrate significant potential in inhibiting starch digestion. However, the poor solubility, poor reactivity and easy degradation of polyphenols limit their effectiveness on starch digestion. The present study aims to avoid polyphenolic limitation in an effective strategy with the utility of rutin nanoparticles, and to co-gelatinize them with rice starch for regulating starch digestibility. SEM and XRD analysis had shown that rutin existed in an amorphous and non-inclusion state within NPS sample. It was accompanied by the absorption peak intensity related to hydrogen bonding weakened and shifted to lower wavenumbers in FTIR analysis. The double-helical domain formation increased from 4.57 % to 6.13 % in 13 CP/MAS NMR analysis. In-vitro digestion study showed that rutin nanoparticles exhibited maximum inhibition of starch digestion. Rutin was gradually released from NPS sample during digestion, with the highest concentration of rutin in its digestive fluid, showing the highest inhibition for digestive enzyme activity with values decreasing from 0.178 U/mL to 0.081 U/mL. Therefore, rutin nanoparticles can significantly regulate starch digestion by altering rice starch structural domains and inhibiting digestive enzyme activity. Overall, this study established a novel strategy to inhibit starch digestion by polyphenol nanoparticles, offering potential applications in low-glycemic starchy foods.