A study revealing volatile aroma produced by in dough fermentation.

is important probiotics in Chinese Laomian. Its role in meat and fermented vegetable has been largely demonstrated, but few studies have investigated the role of in Chinese Laomian. For this purpose, we simulated Laomian fermentation using and . Volatile aroma was detected by headspace solid-phase microextraction gas-chromatography-mass spectrometry. Real-time fluorescent quantitative polymerase chain reaction was used to determine dynamic growth of and in fermentation. Extracellular proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Folin-Ciocalteu method was used to detect extracellular protease activity in different pH values. Owing to addition of the types and contents of esters increase, the relative contents of acetic acid hexyl ester, formic acid octyl ester, and heptanoic acid ethyl ester rise obliviously; especially, the relative content of hexanoic acid ethyl ester was highly correlated with by increasing 20.61%. As the gel electrophoresis results display, due to mixed fermentation of and , the 25k Da and 51k Da proteins expression quantity of clearly increased. Under neutral and alkaline culture conditions, the extracellular protease activity of is higher. This research benefits to gain insight into the fermentation actions of in Chinese Laomian.