Comparison of Viability of Encapsulated Probiotics Bacillus subtilis and Lacticaseibacillus casei in Simulated Gastrointestinal Conditions and Their Survival in Yogurt

In this study, the behavior of encapsulated probiotics Lacticaseibacillus casei and Bacillus subtilis was analyzed with respect to their release capacity, survival under gastric conditions, and viability during storage in yogurt. The probiotics were microencapsulated in four materials: (1) sodium alginate dissolved in cheese whey (SAW); (2) pectin in SAW (SAW-P); (3) gelatin in SAW (SAW-G); and (4) starch in SAW (SAW-S). The encapsulation systems were evaluated in terms of their size, surface morphology, and encapsulation efficiency. Cell release and survival were measured under gastric conditions for 4 h. Afterwards, the encapsulated probiotics were stored in a commercial yogurt beverage for 30 days, and cell survival and the effects on yogurt properties were evaluated. The probiotics showed encapsulation efficiencies in the range of 90–95%. After 4 h of digestion, Lacticaseibacillus casei showed 95% of cells released from SAW, while SAW-G and SAW-P released 25–30% of cells alive. By contrast, SAW released 80% of Bacillus subtilis cells, and SAW-S and SAW-G preserved 30–40% of the probiotic in the capsules. During 30 days of storage in yogurt, both free and encapsulated probiotics showed high cell survival, while the greatest variations in pH and yogurt composition were observed in samples with Lacticaseibacillus casei.