Aggregates of octenylsuccinate oat β-glucan as novel capsules to stabilize curcumin over food processing, storage and digestive fluids and to enhance its bioavailability

Abstract

Self-aggregates of octenylsuccinate oat β-glucan (A_OSG) have been verified as nanocapsules to load curcumin, a representative of hydrophobic phytochemicals. This study primarily investigated the stability of curcumin-loaded A_OSGs over food processing, storage and digestive fluids. Curcumin in A_OSGs showed better stability over storage and thermal treatment than its free form. Curcumin loaded in A_OSGs stored at 4 °C in the dark exhibited higher stability than that at higher temperatures or exposed to light. Approximately 18% of curcumin was lost after five freeze-thaw cycles. Curcumin in A_OSG was more stable than its free form in mimetic intestinal fluids, attesting to the effective protection of A_OSG for curcumin over digestive environments. When curcumin-loaded A_OSG travelled across mimetic gastric and intestinal fluids, curcumin was tightly accommodated in the capsule, while it rapidly escaped as the capsule reached the colon. Interestingly, the curcumin loaded in A_OSG generated higher values of C_max and area under the curve than did its free counterpart. These observations showed that A_OSG is a powerful vehicle for stabilizing hydrophobic phytochemicals in food processing and storage, facilitating their colon-targeted delivery and enhancing their bioavailability.