W1/O/W2 emulsion stabilized by β-lactoglobulin/exopolysaccharides/epigallocatechin gallate complex: Protective effects on Lactobacillus plantarum A81 during storage, pasteurization and gastrointestinal digestion.
The efficacy of probiotics is limited by their low survival capacity in human gastrointestinal tract. In this study, a water-in-oil-in-water (W1/O/W2) emulsion delivery system stabilized by a ternary complex composed of β-lactoglobulin (β-LG), exopolysaccharide (EPS) and epigallocatechin gallate (EGCG) was constructed to encapsulate L. plantarum A81. Compared with native β-LG and binary β-LG-EPS complexes, the β-LG-EPS-EGCG ternary complex significantly decreased emulsion droplet size, improved interfacial protein adsorption efficiency, and formed a denser, elastic interfacial structure. Confocal laser scanning microscopy confirmed more uniform droplet distribution and favorable bacterial encapsulation in ternary complex-stabilized emulsions. Furthermore, the emulsion stabilized by β-LG-EPS-EGCG complex significantly improved the survival rate of strains during 30-day storage (from 27.62% ± 1.35% to 47.33% ± 1.23%), after pasteurization (from 10.55% ± 1.24% to 18.87% ± 1.56%), and after in vitro simulated gastrointestinal digestion (from 3.01% ± 0.81% to 8.97% ± 1.37%). These results demonstrate that β-LG-EPS-EGCG ternary complex is a good stabilizer for W1/O/W2 emulsion.