Electrostatic spraying encapsulation of probiotic-loaded W/O/W emulsion in sodium alginate microspheres to enhance probiotic survival stability.

Water-oil-water (W/O/W) double emulsions have been widely studied and applied in probiotic encapsulation. However, challenges remain in enhancing emulsion stability, protecting encapsulated probiotics from adverse environmental conditions, and improving their viability. This study aimed to optimize the functional components of each phase of the W/O/W emulsion to address these issues. First, the prebiotic fructooligosaccharide, which promotes bacterial growth, was incorporated into the inner water phase. The oil phase (O) was composed of sunflower oil, polyglyceryl polyricinoleate, and different proportions of cocoa butter to investigate the critical role of cocoa butter in maintaining emulsion stability. The effect of varying ratios of whey protein isolate and gum arabic complexes in the outermost water phase on emulsion stability was also systematically investigated. Finally, combined with electrostatic spraying technology, sodium alginate was used as the encapsulating wall material for the probiotic-encapsulated emulsion, and the stability of the system during in vitro gastrointestinal digestion was evaluated. This study utilized electrostatic spray technology to create a protective "armor" around the emulsion encapsulating probiotics. The combination of emulsion encapsulation and electrostatic spray encapsulation significantly improved the survival stability of probiotics, providing a method for maintaining high viability in complex food media.