Decoding the key compounds responsible for the empty cup aroma of soy sauce aroma type baijiu

The empty cup aroma in soy sauce aroma type baijiu (SSB) is distinct, but the specific compounds responsible for its unique aroma remain unknown. The aroma characteristics of SSB and the empty cup were investigated using molecular sensory science. Fifty-three and 27 aroma active compounds were identified in SSB and empty cup aroma, respectively. AEDA of the empty cup showed ethyl 3-phenylpropanoate, phenylethyl alcohol, sotolon, p-cresol, and 2,3-dimethyl-5-ethyl pyrazine could be the most important aroma contributors to the empty cup aroma due to their high FD values. Sotolon, characterized by its seasoning-like and herbal aroma, was identified as a crucial aroma compound for the empty cup aroma for the first time. Lactic acid was found to decrease the olfactory threshold of sotolon markedly in both 53% ethanol water solution and empty cup, promoting the contribution of sotolon to the empty cup aroma.