Analysis of volatile compounds in paocai fermented in different vegetable raw materials

To explore the characteristic volatile components of paocai and their differences in different raw materials,the volatile compounds in 6 typical paocai vegetables(ginger,paocai radish,paocai radish,paocai mustard tuber and paocai garlic)were detected by head space solid phase microextraction gas chromatography mass spectrometry(HS-SPME-GC-MS).Principal component analysis(PCA)showed that the main volatile components of pickles can be divided into two categories according to the degree of fermentation.A class of fully fermented vegetables,the main volatile constituents from fermentation and raw material,such as radish,cabbage,mustard produced by fermentation of ethanol,acetic acid and esters,including from itself,their own raw materials of Allyl isothiocyanate etc.Another type of vegetable which is not fully fermented,the volatile components are mainly from itself,such as bubble garlic,the main volatile components are Diallyldisulfide and so on. In fermented vegetables,the flavor of fermented mustard tuber,green vegetable and radish was different,even after the same type of different varieties,such as long radish and round radish,the volatile components were also different after fermentation.Ethanol,Phenethyl alcohol,2-Ethylhexanol,Acetic acid,Butyric acid and Ethyl acetate can be used to distinguish between fermented and non fermented pickles,in which Phenethyl alcohol and 2-Ethylhexanol can be used to distinguish between paocai long radish and paocai round radish.