Distribution of volatile sulfur compounds in an interspecific hybrid between onion (Allium cepa L) and leek (Allium porrum L)

Volatile sulfur compounds of an interspecific hybrid between Allium cepa an d Allium porrum were analyzed by gas chromatography (GC) and GC/mass spectr ometry prior to isolation of the individual oils by a simultaneous distilla tion/extraxtion (SDE) method. Furthermore, the aroma profiles of various on ion and leek cultivars were investigated. Major volatile components detecte d in onion were 2-methyl-2-pentenal, (E)-methyl 1-propenyl disulfide, methy l propyl trisulfide, and propanethiol, whereas dipropyl trisulfide, dipropy l disulfide, and (E)-propenyl propyl disulfide predominated in leek oils. A ccording to the higher amount of leek chromosomes in the cell nucleus, the percentages of the measured sulfur volatiles in the hybrid material corresp ond more to the leek than to the onion flavor profile. Discrimination analy sis was successfully applied to classify the three predefined Allium groups . It has been found that at minimum five of the most important aroma volati les were necessary to receive sufficient differentiated clusters without an y overlapping areas. This graphical display demonstrates very clearly the i nfluence of the genetic background of the parent varieties on the sulfur vo latile composition in the Allium hybrid.