Comparative Analysis of Pyrazine Compounds in Soy Sauce Aroma Baijiu from Different Regions and Their Impact on Flavor Profiles

Pyrazines represent critically important flavor compounds in soy sauce aroma Baijiu. This study identified 36 pyrazine compounds in soy sauce aroma Baijiu across two production regions using GC×GC-TOFMS, with 24 quantitatively analyzed through GC-MS/MS coupled with liquid-liquid microextraction(LLME). Quantitative results revealed significant differences in pyrazine concentrations between the two production regions, which were attributed to distinct terroir characteristics and microbial compositions. Total pyrazine content progressively increased with production cycles in both regions. Regional climatic influences manifested as substantially higher pyrazine levels (especially TTMP) in Maotai Town compared with Shennongjia during the first five production cycles, though this disparity diminished in later cycles. Odor Activity Value (OAV) analysis indicated minimal inter-regional differences in direct flavor contribution of pyrazine compounds, with only four pyrazines exhibiting OAVs>1. The majority of pyrazines compounds demonstrated negligible direct impact on characteristic aroma formation (OAVs<1). Further investigation of pyrazine-ester interactions revealed that pyrazines predominantly enhanced ester aroma perception in 53% (v/v) ethanol solutions. Crucially, despite sub-threshold concentrations of most of pyrazine compounds, these compounds could affect Baijiu flavor through perceptual interactions. These findings establish a theoretical foundation for targeted flavor modulation in soy sauce aroma Baijiu production.