Abstract:Gas chromatography-ion mobility spectroscopy （GC-IMS）,combined with multivariate statistical analysis were employed to analyze the volatile flavor compounds in Maotai-flavor Baijiu samples from eight fermentation rounds during the brewing process.The results showed that 19 esters,8 aldehydes,7 alcohols,6 ketones,and 1 furan were identified from 8 rounds of Baijiu.The composition and content of volatile compounds varied in the samples from different fermentation rounds,which were clustered into four groups：the first and second rounds,the third and fourth rounds,the fifth and sixth rounds,and the seventh and eighth rounds,among which there were 14 differential compounds.The relative odor activity value（ROAV） revealed 12 key flavor compounds in different clusters,including ethyl caproate,ethyl 3-methylbutyrate,ethyl valerate,propionaldehyde,ethyl butyrate,amyl acetate,ethyl isobutyrate,ethyl octanoate,3-methylbutyraldehyde,isoamyl acetate,2-n-butylfuran,and propyl butyrate.Among them,ethyl caproate,ethyl 3-methylbutyrate,and ethyl valerate with ROAV>50 showed the most contribution to the flavor of Baijiu.The comprehensive analysis showed that the samples from the fifth and sixth rounds had the best flavor,followed by those from the third and fourth rounds.