Effects of alcalase hydrolysis combined with TGase-type glycosylation of self-assembled zein for curcumin delivery: Stability, bioavailability, and antioxidant properties.

Abstract

In this study, zein was hydrolyzed by alcalase and conjugated to oligochitosan under transglutaminase (TGase) catalysis to construct novel self-assembly complex for the delivery of curcumin. The effects of enzyme hydrolysis and TGase-type glycosylation of zein/curcumin on the stability, bioavailability, and antioxidant properties were evaluated. The obtained glycosylated zein hydrolysate had a uniform distribution and small particle sizes. Structural analysis revealed that the primary forces within the curcumin-loaded glycosylated zein hydrolysate complex were electrostatic interactions, hydrogen bonding, and hydrophobic interactions. The prepared complex demonstrated excellent encapsulation efficiency for curcumin (82.19 %). Oligochitosan formed a protective layer around zein hydrolysate/curcumin complex through covalent binding, effectively resisting the degradation caused by gastric enzymes. This significantly increased the retention rate during the undigested stage and facilitated the release of curcumin in the intestine, thereby enhancing the bioavailability. This study offers new insights into using hydrolysis combined with TGase-type glycosylation of protein as a delivery system to protect hydrophobic nutrients.