Characterization of volatile aroma compounds in pak choi

Aroma is a key sensory factor in the flavor evaluation of pak choi (Brassica rapa L. ssp. chinensis var. Makino). The pak choi varieties Xiangqingcai (XQC) and Xiuhuajin (XHJ) have unique aroma characteristics, but the chemical profiles of these aromas are unknown. Here, the aroma profiles of three varieties of pak choi including XQC, XHJ, and Suzhouqing (CK, non-aromatic) were determined using gas chromatography–mass spectrometry (GC–MS) and relative odor activity values (rOAV). A total of 15 categories of 716 volatile metabolites were detected in the three pak choi varieties, with terpenoid metabolites identified as the major components, although in each sample the identity of the major terpenoid metabolite varied. There were 53 aroma components in XQC and 54 aroma components in XHJ with rOAV >1, which contribute to rice aroma and fishy odor of these varieties, respectively. •Volatile metabolites of pak choi were analyzed.•716 volatile compounds were identified; terpenoids were the primary volatile compounds of pak choi.•141 differential metabolites in 13 categories were identified, and terpenoids were the primary differential metabolites.•Key aroma compounds of two aromatic pak choi varieties were identified.