Changes in Volatiles during Pickling of Root Mustard (Brassica juncea Coss.var.megarrhiza Tsen et Lee)
The volatile flavor compounds of pickled root mustard (Brassicajuncea Coss.var.megarrhiza Tsen et Lee)were extracted by solid phase microextraction (SPME) and analyzed by gas chromatograph-mass spectrometry (GC-MS).A total of 33 volatile compounds,including esters,acids,alcohols,aldehydes,alkanes,nitriles and nitrogenous compounds were identified in fresh,30 d and 90 d pickled root mustards.Esters were the most abundant of these compounds followed by acids.During the pickling period,the number of esters,acids,alcohols,alkanes and nitrogenous compounds increased,whereas the number of aldehydes decreased.In addition,allyl isothiocyanate and 2-phenethyl isothiocyanate responsible for the pungent flavor were degraded.The esters making important contributions to flavor development were formed at the late stage of pickling.Acids and alcohols were accumulated as a result of lactic acid and alcohol fermentation.Ethyl palmitate,ethyl linolenate,methyl palmitate,methyl linolenate,linoleic acid methyl ester,linoleic acid ethyl ester and benzenecarboxylie acid were primarily identified as the main flavor compounds in root mustard.