DETERMINATION OF FLAVOR PRECURSOR COMPOUND S-ALK(EN)YL-L-CYSTEINE SULFOXIDES BY AN HPLC METHOD AND THEIR DISTRIBUTION IN ALLIUM SPECIES

Pungency precursor compounds, S-methyl (Me), S-2-propenyl (allyl, Al)- , and S-propenyl (Pe)-L-cysteine sulfoxides (CSO), were determined fro m eight Allium species plants using high performance liquid chromatogr aphy after dansyl-Cl derivatization. Allium plants selectively contain ed two or three kinds of CSOs with varying amounts and proportions, co rresponding to their flavors. MeCSO was a major precursor in chive and Chinese chive (0.68-1.85 mg g(-1) fresh wt.) and found in all the spe cies examined with less amounts. AlCSO was the major precursor in garl ic and giant garlic (3.2-9.8 mg g(-1)), and was also contained in chiv e and Chinese chive. PeCSO was the main flavor precursor in onion, gre en onion, leek, and shallot (0.3-2.2 mg g(-1)), but also found in chiv e, Chinese chive, garlic and giant garlic. Garlic and giant garlic con tained greatest amounts of total CSO (5.0-11.7 mg g(-1)), while Chines e chive, dehydrator onion, leek, shallot had moderate amounts (2.0-5.0 mg g(-1)). Japanese bunching onion, onion (TG 1015Y), and chive leave s contained least amounts of total CSO (<2 me g(-1)). S-propyl CSO, ho wever, was not found in any of these species. Based on the composition of the precursors, we could classify the Alliums species into three g roups, such as Me-, Al-, and PeCSO dominant groups. (C) 1998 Elsevier Science B.V.