Characterization of key aroma compounds in Chinese Guojing sesame-flavor Baijiu by means of molecular sensory science

Key odorants of Guojing sesame-flavor Baijiu were identified using the concept of molecular sensory science, including aroma extract dilution analysis (AEDA) based on gas chromatography-olfactometry (GC-O) combined with gas chromatography-mass spectrometry (GC-MS). A total of 509 volatile compounds were detected by comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC x GC-TOF-MS). Sixty-one aroma-active compounds were identified via AEDA. Among them, two compounds with strong roasted aroma showed the highest flavor dilution (FD) factors of 19,683 and 6561. By using pure standards, aroma tests, and GC-MS, the compound with FD = 19683 was identified as benzenemethanethiol, which is reported for the first time in Baijiu. Sixty compounds were quantified by means of internal standard curve method, and 39 of them had odor activity values (OAVs) >= 1. Ethyl hexanoate, ethyl octanoate, and dimethyl trisulfide showed the highest OAVs, indicating that they contribute significantly to the aroma of Guojing sesame-flavor Baijiu.