Effects of Bacillus subtilis on the Stability of Soybean Protein-Phospholipid Composite Emulsion in Vitro Digestion

To investigate the effect of Bacillus subtilis on the stability of a soy protein-phospholipid complex emulsion during digestion. This experiment designed a gastrointestinal digestion model,calculated the emulsification activity index(EAI),emulsification stability index(ESI),turbidity,particle size,Zeta potential,and conducted microscopic observation for O/W and W/O emulsions with and without bacteria to investigate whether the emulsion was separated and flocculated,gathering and floating phenomenon. The results showed that in the digestive stage of the stomach,the EAI,ESI,particle size,and Zeta potential of the O/W and W/O emulsions all significantly reduced,and the micrograph showed that the droplet density reduced and the volume increased. Compared with the without bactericidal emulsion,the index of the emulsion decreased more significantly. In the digestive stage of the small intestine,the EAI and ESI of the O/W and W/O emulsions showed an overall upward trend,while the particle size and potential decreased significantly. In addition,the micrographs of both showed a decrease in droplet density and volume. After adding Bacillus subtilis,the EAI,ESI,particle size of the emulsion significantly reduced,and the potential significantly increased(P<0.05). Based on the above results, Bacillus subtilis promoted the demulsification of soybean protein-phospholipid complex emulsion during digestion.