title: Genotypic and climatic influence on the antioxidant activity of flavonoids in Kale (Brassica oleracea var. sabellica).
abstract: The influence of genotype and climatic factors, e.g. mean temperature and mean global radiation level, on the antioxidant activity of kale was investigated. Therefore, eight kale cultivars, hybrid and traditional, old cultivars, were grown in a field experiment and harvested at four different times. In addition to the investigation of the total phenolic content, the overall antioxidant activity was determined by TEAC assay and electron spin resonance spectrometry. A special aim was to characterize the contribution of single flavonoids to the overall antioxidant activity using an HPLC-online TEAC approach. The antioxidant activity and the total phenolic content were influenced by the genotype and the eco-physiological factors. The HPLC-online TEAC results showed that not all flavonol glycosides contribute to the overall antioxidant activity in the same manner. Taking the results of the structural analysis obtained by HPLC-ESI-MS(n) into account, distinct structure-antioxidant relationships have been observed.
authors.affiliation: Institute of Food Technology and Food Chemistry, Technische Universitat Berlin, Gustav-Meyer-Allee 25, D-13355 Berlin, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Zietz
authors.forename: Annika
authors.initials: A
authors.lastname: Weckmüller
authors.forename: Susanne
authors.initials: S
authors.lastname: Schmidt
authors.forename: Sascha
authors.initials: S
authors.lastname: Rohn
authors.forename: Monika
authors.initials: M
authors.lastname: Schreiner
authors.forename: Angelika
authors.initials: A
authors.lastname: Krumbein
authors.forename: Lothar W
authors.initials: LW
authors.lastname: Kroh
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D052160:Benzothiazoles; D001937:Brassica / Q000737:chemistry* / Q000235:genetics; D002839:Chromans / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D002980:Climate; D003124:Colorimetry; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D005419:Flavonoids / Q000032:analysis / Q000378:metabolism; D016166:Free Radical Scavengers / Q000032:analysis / Q000378:metabolism; D005838:Genotype; D010636:Phenols / Q000032:analysis* / Q000302:isolation & purification; D021241:Spectrometry, Mass, Electrospray Ionization; D013451:Sulfonic Acids
chemical_list: D000975:Antioxidants; D052160:Benzothiazoles; D002839:Chromans; D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid