Effects of Bacillus coagulans GBI-30, 6086 as an adjunct starter culture on the production of yogurt

The effects of Bacillus coagulans GBI-30, 6086 (BC30) as supplementation on yogurt fermentation and storage were investigated in this study. Over 14 d of storage at 4 °C, we monitored changes in multiple parameters, including pH, titratable acidity, bacterial level, texture profiles, volatile flavor compounds, and sensory quality. BC30 supplementation improved fermented milk acidification and proteolysis. The bacterial level was significantly higher at the fermentation termination (5.59 log CFU/mL) than the fermentation initiation (6.86 log CFU/mL) (P < 0.05), indicating that BC30 own the potential to serve as an adjunct start culture. During the storage period, a high bacterial level of BC30 was detected. With prolonged storage, the yogurt samples supplemented with BC30 showed a decrease in firmness and an increase in viscosity. Furthermore, 12 discriminatory volatiles of BC30 fermented yogurt were detected during storage. Notably, the contents of some important diketones (2,3-butanedione and 3-hydroxy-2-butanone) increased continuously during storage, peaking at 14 d. The BC30-supplemented fermented milk had similar human sensory scores to the control group. Comparative genomic analysis between BC30 and B. coagulans-70 indicated that both these two strains showed the potentially to survive in the dairy environment. Our results will be of interest to the dairy industry to develop novel functional dairy products.