Curcumin-loaded WPI-FUC emulsion as a microcapsule core material enhances the applicability and stability of curcumin—preparation and characterization of a new type of microcapsule

Emulsions stabilized by protein-polysaccharide complexes are effective carriers for delivering hydrophobic active substances, such as curcumin. Traditional microcapsules prepared using emulsions to load curcumin often exhibit unfavorable storage stability and applicability due to the susceptibility of the oils in the emulsion to oxidation. To address these two issues, this study first examined the stability and curcumin encapsulation efficiency of Emulsion I: a whey protein isolate (WPI) single-layer emulsion, Emulsion II: a WPI-fucoidan (FUC) single-layer emulsion, and Emulsion III: a WPI-FUC double-layer emulsion. Among them, due to the good spatial effect and electrostatic interaction of the WPI-FUC complex, which can inhibit the aggregation of droplets, the curcumin-loaded emulsion II has the best stability. Subsequently, we used curcumin-loaded Emulsion II as the core material, and maltodextrin (MD), inulin (IN), and maltodextrin-inulin complex (MD-IN), which are almost lipid-free and less prone to oxidation, individually as the wall materials, to prepare microcapsules through spray drying and freeze-drying processes. Microcapsules prepared with MD-IN as the wall material by spray drying have the optimal solubility, storage stability, and encapsulation efficiency. This novel microcapsule structure provides a certain data basis for the better application of the active substance in the food industry.