Comparison of protein hydrolysates against their native counterparts in terms of structural and antioxidant properties, and when used as emulsifiers for curcumin nanoemulsions

Abstract

This study investigated the stability and the in vitro digestion of curcumin nanoemulsions stabilized by three protein hydrolysates: peanut protein isolate (PPI), soybean protein isolate (SPI) and whey protein isolate (WPI). After enzymatic hydrolysis, the protein structure became more disordered, and increased antioxidant capacity was also observed for protein hydrolysates. The protein hydrolysates generated curcumin nanoemulsions with considerable stability over 28 days of storage. Moreover, protein hydrolysates more effectively improved the lipolysis rate and bioaccessibility of curcumin nanoemulsions than native proteins, and PPI hydrolysates exhibited the highest lipolysis rate (110.43%) and the highest bioaccessibility (53.24%). This study indicated that protein hydrolysates could be used as emulsifiers for preparing nanoemulsion delivery systems with high stability and bioaccessibility.