Encapsulation of Enterococcus faecium E297 by Double Emulsion (W ₁ /O/W ₂ ) with Milk Protein Fractions: Stability under Technological and Simulated Digestive Stress, and Antimicrobial Potential in a Functional Dairy Dessert

This study evaluated the protective effect of double-emulsion (W1/O/W2) encapsulation of Enterococcus faecium E297 using milk protein fractions under technological stress and simulated gastrointestinal digestion, as well as its antimicrobial potential in a functional dairy dessert. Encapsulation efficiencies exceeded 90%. E. faecium E297 exhibited moderate adhesion capacity, determined by surface hydrophobicity assay, and antagonistic activity against E. coli, reducing counts by 3.49 log CFU/mL in coculture. Casein-based microcapsules enhanced tolerance to acidic, alkaline, 5% NaCl, and thermal stress and improved stability during storage at 25 °C, maintaining counts above 6.0 log CFU/mL. Moreover, they demonstrated highest resistance during simulated gastrointestinal digestion, with 83.77% survival. In the dairy dessert, E. faecium E297 maintained viable counts consistent with probiotic standards and reduced E. coli by up to 6.0 log CFU/g during storage. These findings indicate that casein-based encapsulation enhances probiotic stability in vitro and may help control E. coli in the product.