Abstract: In this study, liquid-liquid extraction combined with gas chromatography-mass spectrometry (LLE-GC-MS) was used to qualitatively and quantitatively analyze the flavor compounds in mechanized sauce-flavor Baijiu base liquors from different fermentation rounds, and their odor activity values (OAVs) were calculated. There were significant differences in the flavor composition of the tested samples, especially esters, alcohols, acids, aldehydes and ketones. Esters played a major role in the flavor composition. The results showed that 12 esters including ethyl lactate, ethyl acetate, ethyl hexanoate, ethyl hexadecate, ethyl oleate, 9,12-octadecadienoic acid, ethyl tetradecanoate, 9-hexadecenoic acid, ethyl stearate, 13-methyltetradecanoic acid, ethyl phenylacetate and phenylethyl acetate were the ‘skeleton esters’ of mechanized sauce-flavor Baijiu base liquor. Ethyl laurate and ethyl tetradecanoate contributed the most to the floral and sweet flavor in the base liquors from the 1st and 2nd rounds of fermentation; ethyl 3-phenylpropionate contributed the most to the honey-like and sweet flavor in the first-round base liquor; ethyl valerate, amyl acetate and ethyl octanoate contributed the most to the fruity, flowery and sweet flavor in the third-, fourth- and fifth-round base liquors, which were the characteristic compounds responsible for harmonizing the aroma of the base liquors. All esters except ethyl oleate and ethyl hexadecate had little contribution to the sixth- and seventh-round base liquors. The flavor composition of mechanized base liquor was similar to that of the traditional one, and the characteristic esters were also similar between them. This study will provide a reference for promoting the mechanization of sauce-flavor Baijiu.

Key words: mechanized sauce-flavor Baijiu; base liquors from different fermentation rounds; gas chromatography-mass spectrometry; flavor composition; esters; aroma activity value