Abstract: Abstract: In order to identify the differences in volatile compounds in fried Pi Xian Douban, solid-phase microextraction gas chromatography mass spectrometry (SPME-GC-MS) and gas chromatography ion mobility spectroscopy (GC-IMS) were used to detect the compounds in fried Pi Xian Douban of different grades, using orthogonal partial least squares discriminant analysis (OPLS-DA) and principal component analysis (PCA), combined with odor activity value (OAV) to determine key compounds. The results showed that SPME-GC-MS identified 88 VOCs, including 15 aldehydes, 11 alcohols, 17 esters, 13 ketones, 5 acids, 5 olefins, 6 alkanes, 7 heterocycles, 2 phenols, and 7 ethers and heterocyclic compounds. The results showed that SPME-GC-MS identified 88 compounds, including 15 aldehydes, 11 alcohols, 17 esters, 13 ketones, 5 acids, 5 alkenes, 6 alkanes, 7 heterocycles, 2 phenols, and 7 ethers and heterocycles. Among them, 34 were common compounds. A total of 57 compounds were identified by GC-IMS, and through OPLS-DA analysis, 16 key compounds affecting flavor with VIP values>1 were identified. OAV value results: Ethyl butyrate made special bean paste present apple aroma, and Isovaleraldehyde brought malt aroma; Ethyl isovalerate makes the first grad bean paste present fruity aroma, and 3-methylthiopropionaldehyde brings roasted potato flavor and soy sauce flavor; Ethyl Isobutyric acid makes the secondary bean paste present fruity aroma, Isovaleraldehyde, Isobutyraldehyde and malt aroma. It can be determined that the overall appearance of stir-fried watercress is fruity, wine flavored, malty, sour, herbaceous, cocoa flavored, and almond flavored. The research results can serve as a reference for determining the aroma characteristics of stir-fried watercress in the future, and provide a reference basis for the early design of sensory attribute description vocabulary using sensory quantitative description methods.

Key words: Key words: Pi Xian Douban, Stir-fry, solid phase micro extraction gas chromatography-mass spectrometry, gas chromatography-ion mobility spectrometry, Flavor compounds