Egg-derived high internal phase emulsions enhance the viability and retention of probiotics during gastrointestinal digestion.

Abstract

Although high internal phase emulsions (HIPEs) have shown potential for probiotic encapsulation, most reported systems mainly provide structural protection and lack multifunctional regulation of gastrointestinal stresses. This study aimed to develop a multifunctional egg-derived HIPEs platform co-stabilized by egg yolk granules (EYGs) and salted egg whites (SEWs), integrating probiotic encapsulation, localized acid-buffering capacity provided by eggshell powder (ESP), and nutritional support to enhance the gastrointestinal delivery efficiency of probiotics. The optimal formulation for Lacticaseibacillus rhamnosus GG (LGG)-loaded HIPEs was identified by particle size and zeta potential measurements together with plate count, corresponding to the system containing 3% galactooligosaccharides (GOS) and 2% LGG. Under this formulation, LGG/GOS@HIPEs exhibited the superior storage stability and probiotic viability after 30 d at 4 °C. The in vitro simulated digestion results demonstrated a marked difference in probiotic survival among the tested groups. Following SGF treatment, LGG/GOS/ESP@HIPEs and LGG/GOS@HIPEs showed lower reductions (0.73 and 0.86 log CFU/mL) than free LGG (2.92 log CFU/mL). Crucially, LGG/GOS/ESP@HIPEs still maintained a viable count of 1.52 ± 0.20 × 106 CFU/mL after gastrointestinal digestion, corresponding to six orders of magnitude increase in survival relative to free probiotics, which were almost completely inactivated. To further evaluate gastrointestinal retention, ICG-labeled probiotics were tracked by In Vivo Imaging System. The system reduced gastrointestinal loss and enhanced intestinal retention of LGG in mice, with nearly 2-fold higher gastrointestinal fluorescence intensity than free probiotics at 15 h. These findings provide a food-grade HIPEs-based strategy for the enhancement of oral probiotic delivery efficiency.