Fabrication and characterization of whey protein-sodium alginate-based emulsion gel beads and their controlled release of curcumin.

The poor stability and low bioavailability of curcumin (CUR) have limited its application in the food industry. The incorporation of hydrophobic compounds into emulsion gels has been shown to enhance their stability and facilitate controlled release from the matrix. Therefore, this study aims to encapsulate CUR in sodium alginate (ALG)-whey protein (WPI)-based emulsion gels to improve its stability and bioavailability. In this study, gel beads were prepared by the oil-in-water emulsions stabilized by ALG and WPI for effective delivery of CUR. The addition of ALG increased the apparent viscosity and induced a Newtonian-like flow behavior, which helped to form a more compact network structure. As the ratio of ALG to WPI varied from 1:3 to 3:1, the swelling ratios of the gel beads were decreased to 44 % and 89 % at pH 1.2 and pH 7.4, respectively, which was attributed to electrostatic interactions and hydrogen bonds between ALG and WPI. In vitro digestion experiments showed that the emulsions-based gel beads could be used for sustained and controlled release of CUR and maintained the antioxidant activities. These results suggest that ALG-WPI emulsions-based gel beads could be effective encapsulation system for bioactive compounds in food industry.