Characterization of key odor-active compounds in aged Chinese grain whisky by sensory-directed flavor analysis and...

Chinese grain whisky possesses distinctive flavor owing to the unique raw materials and barrel aging process, yet its aroma chemistry has not yet been fully studied. All the odor compounds of aged whisky were initially determined by two-dimensional gas chromatography-mass spectrometry (GC × GC-MS) with solid-phase microextraction (SPME) and liquid-liquid extraction (LLE). A total of 43 odor-active compounds were identified by aroma extract dilution analysis (AEDA) with gas chromatography-olfactometry-mass spectrometry (GC-O-MS), with 31 compounds (OAV ≥ 1) confirmed. Moreover, the aroma recombination successfully replicated the original sensory profile (fruit, coconut, flower, acid, and vanilla), while the omission experiments demonstrated ethyl 2-methylbutanoate, ethyl octanoate, vanillin, whisky lactone, β-damascenone, 2-phenylethanol and 3-methylbutanoic acid were indispensable. Finally, OR1A1 exhibited the strong binding energy to β-damascenone, vanillin, whisky lactone and 2-phenylethanol through the hydrogen bonding and hydrophobic interactions. Therefore, comparing pre- and post-aging profiles confirmed critical odorants, providing a foundation for aroma control and quality standardization.