DMU-SPME variable temperature extraction: Revealing the flavor characteristics of strong-aroma baijiu by volatilomics.

Comprehensive determination of volatilomics in strong-aroma Baijiu, including volatility and low-volatility, poses significant challenge but is crucial for volatilomics research in Baijiu and other spirits. This study developed a dual-mode unity solid-phase microextraction (DMU-SPME) approach combined with variable-temperature extraction (involving NaCl addition and fiber immersion depth optimization) and gas chromatography-mass spectrometry (GC-MS) to establish a rapid and simultaneous method for determining both volatility and low-volatility in strong-aroma Baijiu. DMU-SPME with variable-temperature extraction identified 103 substances, exceeding headspace SPME (HS-SPME) by 32 and immersion SPME (DI-SPME) by 25, while uniquely extracting 19 compounds undetectable by either method. Analysis of three strong-aroma Baijiu samples revealed 46 common characteristic flavor compounds (11 with RI > 1560) and 36 unique flavor compounds (VIP > 1.0; 11 with RI > 1560). DMU-SPME combined with variable-temperature extraction demonstrated superior efficiency for volatilomics, enabling enhanced equilibrium and adsorption of diverse aroma compounds in Baijiu and other spirits.