Encapsulation of Lacticaseibacillus paracasei ProSci-92 in sodium alginate/soy protein isolate by endogenous emulsification: Enhanced viability and storage of probiotics

The stability and efficacy of probiotics can be significantly enhanced by adopting micro-encapsulation techniques. In this study, sodium alginate (SA) and soy protein isolate (SPI) were utilized as wall materials for Lacticaseibacillus paracasei ProSci-92 microencapsulation through extrusion and endogenous emulsification methods. The key metric was encapsulation efficiency (EE), and other optimal process parameters were determined by performing single-factor and orthogonal tests. Compared with extrusion, endogenous emulsification achieved a significantly higher EE (92.17 %) under the following optimized conditions: SA concentration, 20 mL/L; SA/CaCO 3 mass ratio, 1:3; SA/SPI mass ratio, 1:3; water/oil volume ratio, 1:3; stirring speed, 400 rpm. The microencapsulated ProSci-92, after freeze-drying, exhibited a 96.31 % survival rate, which was 17.92 % higher than reported for the unencapsulated cells. After 11 h of in vitro incubation with simulated gastrointestinal fluids, the survival rate remained 80.20 %. After 28 days of storage stability tests, enhanced survival rates of 11.61 % (at 4 °C) and 17.40 % (at 25 °C) were observed. Thus, the microcapsules demonstrated superior tolerance, resistance to stress, and storage stability, laying a theoretical foundation for developing probiotic-based commercial products. • Probiotics were encapsulated by endogenous emulsification methods. • SA-SPI composite wall material enhanced encapsulated probiotics' resistance to harsh conditions. • Microcapsule probiotics demonstrated excellent stability during storage.