Analysis of Volatile Flavor Components in Zizhong Dongjian, Dry Cured Fermented Leaf Mustard

The volatile flavor compounds of Zizhong Dongjian(dry cured fermented leaf mustard in Zizhong,Sichuan province) fermented for 1,2,3 or 4 yeatrs were extracted by headspace solid phase micro extraction(HS-SPME) method and analyzed by gas chromatography-mass spectrometry(GC-MS).A total of 147 compounds divided into 9 categories were identified in four Dongjian samples,among which 11 components were predominant including palmitic acid ethyl ester,octanoic acid ethyl ester,heptadecane and beta-ionone.Over 4 years of fermentation,the types of major volatile flavor components and their relative contents revealed significant differences.On the 1st year fermentation,hydrocarbons were the most abundant compounds,while esters instead of hydrocarbons became main components on the 2nd to 4th year fermentation.On the 4th year fermentation,the relative contents of ketones and sulphur compounds increased dramatically.Eight components were common to all the four samples,all of which were domniant volatile compounds in Dongjian.Furthermore,Dongjian samples fermented for different years had different flavors due to their varying volatile composition.