Preparation of a double emulsion loaded with bifidobacteria and its effect on improving intestinal immune function of mice

Abstract With bifidobacteria as the embedded strain, double emulsions were prepared with a two-step emulsification method, with food-grade materials serving as the oil phase and the external aqueous phase. The optimal conditions for emulsion preparation were determined through preliminary experiments: the W/O emulsion to external aqueous phase mass ratio was 4:6, the internal aqueous phase to oil phase mass ratio was 4:6, the whey protein to low-ester pectin mass ratio was 2:1, and the concentration of PGPR in the oil phase was 3.5%. The particle sizes of the emulsions after ultrasonic treatment showed a single-peak distribution within the range of 10–100 μm. After 30 min of heat treatment at 50 °C, the viable count remained 3.99 log CFU mL −1 higher than that of the control. Compared with the un-embedded samples, the viable count remained 4.44 log CFU mL −1 higher after simulated digestion. After validation in animal experiments, the concentrations of proinflammatory factors in the mice fed with high-concentration double emulsions decreased compared with the model group, and the intestinal hormone levels were close to those of the normal group, indicating that the emulsions can provide sufficient bifidobacteria to regulate the intestinal environment.