Microencapsulation of Bifidobacterium breve to enhance microbial cell viability in green soybean yogurt

Bifidobacteria, a major bacterial group, have several beneficial impacts on health, such as enhancing the intestinal flora by limiting the colonization of pathogenic microorganisms and stimulating the immune system. As a result, bifidobacteria have been extensively included in various food products. In this study, Bifidobacterium breve TISTR 2130 was microencapsulated using an emulsion technique with sodium alginate and calcium lactate in green soybean milk as wall materials. This study found that microbeads prepared with 2.0% (w/v) sodium alginate and 2.0% (w/v) calcium lactate had the highest microencapsulation efficiency (MEE) of 99.8% ± 0.07%. In addition, the viability of microencapsulated B. breve TISTR 2130 and free cells was evaluated following a simulated gastrointestinal treatment. Microencapsulated B. breve TISTR 2130 showed higher cell viability than free cells under the simulated gastrointestinal conditions. The viability reduction of free cells dropped substantially to zero after 1 h of incubation in simulated gastrointestinal juice (SIJ), while the viable cell count of microencapsulated B. breve TISTR 2130 remained greater than 5 log CFU/mL and the survival rate was greater than 64% at the end of the sequential digestion. During refrigerated storage of green soybean yogurt (GSY) fortified with microencapsulated B. breve, the viability of B. breve TISTR 2130, syneresis, and acidity decreased, while the pH and viscosity increased. Microencapsulated B. breve TISTR 2130 has the potential to be used as a probiotic fortification in GSY since the viability remained above the recommended minimal limit of 6 log CFU/mL for 10 days during refrigerated storage. The present study demonstrated that the optimized microencapsulated B. breve TISTR 2130 sodium alginate matrix could survive the human gastrointestinal tract to provide health benefits and the possibility of incorporation into functional foods.