Effect of bread ingredients and baking techniques on Bacillus coagulans GBI-30 viability during baking and in vitro digestion

Abstract

This study aimed to investigate the effect of bread ingredients and baking techniques on the viability of Bacillus coagulans GBI-30 spores during baking and in vitro digestion conditions. After baking, the highest B. coagulans viability were observed in the bread formulation with low sugar and high oil content. Among the baking techniques, steam-assisted baking (ST-HA) resulted in the highest B. coagulans count (7.46 log CFU/g) and viability (95.31%). Conversely, microwave-assisted baking (MW-HA) yielded the lowest B. coagulans count (6.91 log CFU/g) and viability (75.50%). The in vitro digestion test results indicated that the highest B. coagulans count was measured with ST-HA in both gastric and intestinal phases with 86.91% and 96.85, respectively. It revealed that B. coagulans probiotic spores are highly resistant to gastric conditions in bread matrix. Furthermore, it was determined that B. coagulans GBI-30 spores incorporated into the bread can germinate under digestion conditions. Different baking techniques also affected the physical quality characteristics of probiotic bread. The highest specific volume was measured in MW-HA, with a value of 3.54 mL/g. However, MW-HA negatively affected the texture properties of bread, as indicated by the highest hardness and chewiness values observed in these bread samples.