Novel Bilayer Emulsions Costabilized by Zein Colloidal Particles and Propylene Glycol Alginate, Part 1: Fabrication and Characterization

In this study, both zein colloidal particles (ZCPs) and propylene glycol alginate (PGA) were simultaneously applied to prepare novel bilayer emulsions using the method of layer-by-layer (LBL) electrostatic deposition. The effects of different concentrations of PGA as well as incorporating sequences of ZCPs and PGA on physical stability and microstructure of bilayer emulsions were investigated. Furthermore, optical microscopy as well as confocal laser scanning microscopy (CLSM) showed that the oil droplets presented uniform spheres and a compact network appeared in bilayer emulsion. Compared to the Pickering emulsion stabilized by ZCPs alone, novel bilayer emulsions exhibited simultaneous and long-term stability against creaming, coalescence, and Ostwald ripening due to the unique interface framework of a particle-polysaccharide hierarchical structure. Novel bilayer emulsions synergistically stabilized by colloidal particles and biopolymers were designed by using interfacial engineering, and a promising pathway was found to produce stable bilayer emulsions for the delivery of bioactive compounds.