Characterization of Retronasal Aroma Differences in High- and Low-Alcohol Jiangxiangxing Baijiu Using Temporal Sensory Evaluation, Retronasal Olfactory Thresholds, and Dose-over-Threshold Analysis

Retronasal aroma strongly influences the flavor quality of low-alcohol Jiangxiangxing Baijiu. This study investigated the retronasal aroma differences between high- and low-alcohol samples (Sample-High and Sample-Low). Dynamic sensory evaluation revealed roasted, grain, floral and fruity, hay, and caramel notes were more pronounced in Sample-High, whereas Sample-Low exhibited stronger fatty and smoky notes, indicating insufficient retronasal aroma richness in Sample-Low. Analysis of 67 compounds showed no significant concentration differences, yet their retronasal olfactory thresholds varied markedly between alcoholic systems (ratio 1.04–4.75), leading to higher dose-over-threshold (DoT) values for several compounds in Sample-Low. Further analysis of the DoT distribution intervals showed Sample-High presented a more balanced distribution, whereas Sample-Low was strongly driven by several high-contribution compounds, which reduced the relative contributions of others. This unbalanced distribution may underlie the lower retronasal aroma richness observed in Sample-Low. These findings provide a new perspective for understanding retronasal aroma in low-alcohol Jiangxiangxing Baijiu.