Characterization of Key Aroma Compounds in Aged Chinese Nongxiangxing Baijiu Based on Sensory and Quantitative Analysis: Emphasis on the Contribution of Trace Compounds

The characteristics and complexity of Baijiu are inseparable from the promotion of aging. While the impact of compounds such as alcohols, esters, and acids on the aroma of aged Baijiu has been extensively studied, the role of other trace compounds in the aging process should not be overlooked. To further investigate the relationship between volatile compounds and the aging of <i>Nongxiangxing</i> Baijiu, sensomics research methods were employed to analyze profiles of young and aged <i>Nongxiangxing</i> Baijiu. In this study, a total of 94 aroma compounds were analyzed in both young and aged <i>Nongxiangxing</i> Baijiu by GC-O/MS. Among these, 12 aroma compounds significantly associated with the aging process were identified by quantification and odor activity values (OAVs). Furthermore, the omission tests result showed that 4-methyl-2-methoxyphenol (2066.79 μg/L), benzaldehyde (3860.30 μg/L), β-phenylethanol (5638.85 μg/L), 3-(methylsulfanyl)propan-1-ol (8.82 μg/L), 3-(methylsulfanyl)propanal (15.91 μg/L), and linalool (17.36 μg/L) were key aroma compounds of aged <i>Nongxiangxing</i> Baijiu. This study reveals that trace compounds contribute to the distinct aroma complexity of aged <i>Nongxiangxing</i> Baijiu, providing a foundation to support aging process analysis.