Effect of enzymolysis and glycosylation on the curcumin nanoemulsions stabilized by β-conglycinin: Formation, stability and in vitro digestion

In this study, the oil-in-water nanoemulsions were prepared by 3% (v/v) MCT oil phase (containing 10 mg/mL curcumin) with 3% (v/v) β-conglycinin hydrolysates (7SH) and 3% (v/v) β-conglycinin-DX-40 conjugates (7SD) as the emulsifiers. In order to explore the effect of enzyme hydrolysis and glycosylation on the nanoemulsions stability, the native β-conglycinin (7S) (3%, v/v) was used as control. The average droplet size of 7SH-stabilized nanoemulsions decreased from degree of hydrolysis (DH) 3%-12%, but then increased after 12%, which revealed that limited enzymolysis should be selected for nanoemulsion preparation. The average droplet size of 7SD-stabilized nanoemulsions was also reduced due to the enhancing on the steric repulsion. Moreover, the stability over various pH of 7SD-stabilized nanoemulsion was improved, especially at the isoelectric point (pI). Although 7SH-stabilized nanoemulsion exhibited slightly worse stability, but it accelerated the cumulative release rate in vitro digestion, which increased cumulative bioaccessibility. This study revealed that both 7SH and 7SD could be used as emulsifier to improve nanoemulsion properties for food applications.