Identification of the key aroma compounds in high-temperature Daqu by integrating GC-MS/O, quantitative measurements, aroma recombination, and omission studies

The aroma of high-temperature Daqu determines its quality and influences the characteristic aroma of Jiangxiangxing Baijiu. In this study, the key aroma compounds of high-temperature Daqu were characterized using molecular sensory science. A total of 144 aroma-active compounds were identified by GC-MS/O after LLE-SAFE and normal phase silica gel chromatography. Notably, 64 compounds, including furaneol, sotolon, 3-methylthiopropanal, isoeugenol, (E, E)-2,4-decadienal and cedrol, were newly identified as aroma-active compounds in high-temperature Daqu. All 144 odorants were quantified using the optimized QuEChERS extraction coupled with UPLC-MS/MS and GC-Orbitrap-MS, and 75 exhibited OAVs >1. Aroma recombination and omission tests using a deodorized Daqu matrix revealed 25 key contributors, including pyrazines (e.g., 2-ethyl-3,5-dimethylpyrazine), furanones (e.g., sotolon, furaneol), acids (e.g., butyric acid), phenols (e.g., isoeugenol), aldehydes (e.g., (E, E)-2,4-decadienal) and sulfur compounds (e.g., 3-methylthiopropanal). These findings underscore the complexity of high-temperature Daqu aroma and provide a scientific basis for understanding its distinct contribution to Jiangxiangxing Baijiu.