title: Influence of cultivar and harvest time on the amounts of isoalliin and methiin in leek (Allium ampeloprasum var. porrum).
abstract: Extracts of 31 leek cultivars were analyzed using liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to determine the distribution of the two most abundant S-alk(en)yl-l-cysteine sulfoxides (ACSOs) in leek, that is, isoalliin and methiin. The isoalliin concentration of the white shaft and green leaves of the 31 leek cultivars varied from 15 to 53 mg/g dry weight (dw) and from 9 to 45 mg/g dw, respectively, whereas the methiin concentration varied from 3 to 16 mg/g dw and from 1 to 10 mg/g dw, respectively. Leek cultivar and tissue had an effect on the ACSO amounts. Cultivars Artico and Apollo F1 rated highest for the mean isoalliin and methiin concentration, respectively. In general, the whole leek plant of the winter leek cultivars contained a significantly higher ACSO amount than the summer and autumn cultivars. To determine whether this difference was attributed to the cultivar background or time of harvest, ACSOs were also quantitated in nine leek hybrids at four different stages during the next growth season. The amounts of ACSO changed significantly during the growth season, indicating the importance of harvest at specific time moments, although there was still an effect of cultivar on the ACSO amounts.
authors.affiliation: Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bernaert
authors.forename: Lien
authors.initials: L
authors.lastname: Goetghebeur
authors.forename: Hervé
authors.initials: H
authors.lastname: De Clercq
authors.forename: Marc
authors.initials: M
authors.lastname: De Loose
authors.forename: Els
authors.initials: E
authors.lastname: Daeseleire
authors.forename: Els
authors.initials: E
authors.lastname: Van Pamel
authors.forename: Erik
authors.initials: E
authors.lastname: Van Bockstaele
authors.forename: Bart
authors.initials: B
authors.lastname: Van Droogenbroeck
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000031:analogs & derivatives* / Q000032:analysis; D057230:Limit of Detection; D019697:Onions / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry
chemical_list: C008389:methiin; C006453:alliin; D003545:Cysteine