Dual-phase bigels from soy hull polysaccharide-soy protein isolate hydrogel and soy lecithin-stearic acid oleogel: A...

In this study, hydrogel was prepared using soy hull polysaccharides (SHP) and soy protein isolate (SPI) as matrices, while oleogel was formulated from soy lecithin (SL) and stearic acid (SA). Bigels with varying oil-to-water ratios (O:H 3:7, 5:5, 7:3) were fabricated and characterized. The O:H 5:5 bigels exhibited the most favorable properties, including superior viscoelasticity, thermal stability, and liquid-holding capacity, together with a uniform and compact microstructure. Encapsulation studies demonstrated that loading Lactiplantibacillus plantarum into the oil phase of the O:H 5:5 bigels achieved the highest encapsulation efficiency (90.3%) and sustained viable counts of 5.47 × 10⁹ CFU/g after 4 weeks of storage. Compared with free probiotics, encapsulated cells displayed markedly enhanced tolerance during in vitro simulated digestion, with survival rates exceeding 87% under gastric conditions and remaining above 60% following intestinal digestion. These findings highlight the potential of soybean-based bigels as an effective carrier for probiotic delivery.