Simultaneous complex coacervation and complex gelation for the encapsulation of fish oil

Complex coacervation is a promising method to prepare solid microcapsule dosages for loading oil. Complex gelation has not been applied to prepare microcapsule carriers for loading oil. Herein, a simultaneous method of bovine bone gelatin (BBG)-gum Arabic (GA) complex coacervation and BBG-maltodextrin (MD) complex gelation at pH 4.0 was developed to prepare fish oil-encapsulated coacervates and powders. The increasing MD/BBG mass ratios (0.0–2.0) increased the bulk densities, tapped densities, and encapsulation efficiencies. In contrast, they decreased the powder sizes, moisture contents, water activities, surface oil contents, and loading capacities. BBG-GA complex coacervation delayed the thermogravimetric behaviors of the fish oil powders. BBG-MD complex gelation affected the thermogravimetric behaviors of the fish oil powders, delayed and reduced oil oxidation in fish oil powders. The fish oil powders could dissolve in the gastric phase to form emulsion droplets and be digested in the small intestinal phase to exponentially release free fatty acids. All these results provided beneficial information to understand the formation mechanism and properties of fish oil powders. It also provided a useful method to develop oil powders for powdered formula foods. • Oil powders were prepared by simultaneous complex coacervation and complex gelation. • Gelatin-maltodextrin complex gelation increased the encapsulation efficiencies of oil. • Gelatin-maltodextrin complex gelation decreased the loading capacities of oil. • Gelatin-maltodextrin complex gelation delayed and reduced oil oxidation. • Oil powders were digested to form emulsion droplets and then to release fatty acids.