Spatiotemporal evolution and mechanistic drivers of alkylpyrazines in Sauce-aroma Baijiu: From brewing to aging

The tracking and regulation of alkylpyrazines (APZ) in Sauce-aroma Baijiu (SSAB) are crucial, as these chemicals significantly influence its distinctive flavor character. However, current research has lacked systematic tracking of APZ across regions and brewing processes. This study developed a highly sensitive and accurate HPLC-FLD method to simultaneously quantify 13 APZ in SSAB and analyzed Baijiu samples across multiple dimensions. A systematic regional analysis indicated significant ( p  < 0.01) variations in APZ concentration, with Guizhou exhibiting the highest average level (29.498 ± 7.511 mg/L), followed by Sichuan, Fujian, and Heilongjiang, driven by meteorological circumstances, environmental quality, and microbial community composition. Further investigation into the formation patterns of APZ during SSAB fermentation showed that peak accumulation occurred in the sixth (28.607 ± 0.952 mg/L) brewing rounds. Kinetic simulation of the aging process demonstrated that the majority of APZ adhere to first-order kinetics. Total APZ demonstrated polynomial development that decelerated after three years, due to precursor depletion, heightened acidity, and competitive responses. These findings underscore the critical roles of raw materials, microbial ecology, and process parameters in shaping the flavor characteristics of SSAB. This study elucidates the transformation behavior of APZ during brewing and its underlying mechanisms, guiding process control and aging optimization of SSAB.