title: Nitrogen split dose fertilization, plant age and frost effects on phytochemical content and sensory properties of curly kale (Brassica oleracea L. var. sabellica).
abstract: We investigated how concentrations of sensory relevant compounds: glucosinolates (GLSs), flavonoid glycosides, hydroxycinnamic acid derivatives and sugars in kale responded to split dose and reduced nitrogen (N) fertilization, plant age and controlled frost exposure. In addition, frost effects on sensory properties combined with N supply were assessed. Seventeen week old kale plants showed decreased aliphatic GLSs at split dose N fertilization; whereas reduced N increased aliphatic and total GLSs. Ontogenetic effects were demonstrated for all compounds: sugars, aliphatic and total GLSs increased throughout plant development, whereas kaempferol and total flavonoid glycosides showed higher concentrations in 13 week old plants. Controlled frost exposure altered sugar composition slightly, but not GLSs or flavonoid glycosides. Reduced N supply resulted in less bitterness, astringency and pungent aroma, whereas frost exposure mainly influenced aroma and texture. N treatment explained most of the sensory variation. Producers should not rely on frost only to obtain altered sensory properties.
authors.affiliation: Department of Food Science, Faculty of Science and Technology, Aarhus University, Kirstinebjergvej 10, Aarslev DK-5792, Denmark. Electronic address: gronbaek@food.au.dk.
authors.forename: Marie
authors.initials: M
authors.lastname: Groenbaek
authors.affiliation: Department of Food Science, Faculty of Science and Technology, Aarhus University, Kirstinebjergvej 10, Aarslev DK-5792, Denmark. Electronic address: sidsel.jensen@carlsberg.com.
authors.forename: Sidsel
authors.initials: S
authors.lastname: Jensen
authors.affiliation: Department Quality, Leibniz-Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e. V., Theodor-Echtermeyer-Weg 1, 14979 Grossbeeren, Germany. Electronic address: neugart@igzev.de.
authors.forename: Susanne
authors.initials: S
authors.lastname: Neugart
authors.affiliation: Department Quality, Leibniz-Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e. V., Theodor-Echtermeyer-Weg 1, 14979 Grossbeeren, Germany. Electronic address: schreiner@igzev.de.
authors.forename: Monika
authors.initials: M
authors.lastname: Schreiner
authors.affiliation: Department of Food Science, Faculty of Science and Technology, Aarhus University, Kirstinebjergvej 10, Aarslev DK-5792, Denmark. Electronic address: ulla.kidmose@food.au.dk.
authors.forename: Ulla
authors.initials: U
authors.lastname: Kidmose
authors.affiliation: Department of Food Science, Faculty of Science and Technology, Aarhus University, Kirstinebjergvej 10, Aarslev DK-5792, Denmark. Electronic address: hanne.kristensen@food.au.dk.
authors.forename: Hanne L
authors.initials: HL
authors.lastname: Kristensen
mesh_terms: D001937:Brassica / Q000737:chemistry* / Q000254:growth & development* / Q000378:metabolism; D005308:Fertilizers / Q000032:analysis*; D005419:Flavonoids / Q000032:analysis / Q000378:metabolism; D005961:Glucosinolates / Q000032:analysis; D006027:Glycosides / Q000032:analysis / Q000378:metabolism; D006801:Humans; D044949:Kaempferols / Q000032:analysis / Q000378:metabolism; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D013649:Taste; D014675:Vegetables / Q000737:chemistry
chemical_list: D005308:Fertilizers; D005419:Flavonoids; D005961:Glucosinolates; D006027:Glycosides; D044949:Kaempferols; C006552:kaempferol; D009584:Nitrogen
keywords: 4-Hydroxy glucobrassicin (PubChem CID: 656561); 4-Methoxy glucobrassicin (PubChem CID: 656563); Controlled frost; Field experiment; Flavonoid glycosides; Fructose (PubChem CID: 5984); Glucobrassicin (PubChem CID: 656506); Glucoiberin (PubChem CID: 9548622); Gluconasturtiin (PubChem CID: 9548618); Glucoraphanin (PubChem CID: 9548633); Glucose (PubChem CID: 5793); Glucosinolates; Sensory quality; Sinigrin (PubChem CID: 23682211); Soluble sugars; Sucrose (PubChem CID: 5988)