Hydrogels assembled from ovotransferrin fibrils and xanthan gum as dihydromyricetin delivery vehicles
The present study aimed to assemble protein fibril–polysaccharide hydrogels as nutraceutical delivery vehicles. Turbidity titrations confirmed that complexations between ovotransferrin (OVT) fibril and xanthan gum (XG) indeed existed, and electrostatic interaction was the major driving force of OVT fibril–XG complexation. After optimization of pH and acidifer, stable OVT fibril–XG hydrogel could be fabricated by adjusting pH to 4.0 with glucono delta-lactone. To better understand physicochemical properties of OVT fibril–XG gel, characterization of XG gel was also conducted. Scanning electron microscopy indicated that OVT fibril–XG gel had denser network than XG gel. Rheological measurements revealed that OVT fibril–XG gel had higher gel strength and viscosity than XG gel. OVT fibril–XG gel and XG gel could be applied as dihydromyricetin (DMY) delivery vehicles with a higher DMY loading (2 mg/mL). DMY release was investigated using in vitro gastrointestinal digestion model. All of DMY was released from OVT fibril–XG gel after gastrointestinal digestion, and only 41.7% of DMY was released from XG gel after gastrointestinal digestion, indicating that OVT fibril–XG gel was more efficient in DMY delivery. DMY was released via non-Fickian transport mechanism in both OVT fibril–XG gel and XG gel. The results in this study could provide new insight into assembly of protein fibril–polysaccharide hydrogels and rational design of hydrogels as nutraceutical delivery vehicles.