title: Effect of Plant Age on the Quantity and Quality of Proteins Extracted from Sugar Beet (Beta vulgaris L.) Leaves.
abstract: Effects of the developmental stage (e.g., young, mature, or senescent) of leaves on their chemical composition have been described in the literature. This study focuses on the variation in chemical composition and quantity and quality of proteins extracted from leaves due to variation in plant age (i.e., harvesting time), using leaves from sugar beets grown in a field (Rhino, Arrival) and in a greenhouse (Isabella). Within the same variety (Rhino, field; Arrival, field; Isabella, greenhouse) the protein content was similar for leaves from young and old plants (22 ± 1, 16 ± 1, and 10 ± 3% w/w db, respectively). Variation in final protein isolation yield was mostly due to variation in nitrogen extractability (28-56%), although no consistent correlation with plant age was found. A significant effect of plant age was observed on the quality (color) of the extracted protein, that is, brown (indicative of polyphenol oxidase activity) and yellow for extracts from old and young plants, respectively.
authors.affiliation: Laboratory of Food Chemistry, Wageningen University , Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kiskini
authors.affiliation: Laboratory of Food Chemistry, Wageningen University , Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
authors.forename: Anne
authors.initials: A
authors.lastname: Vissers
authors.affiliation: Laboratory of Food Chemistry, Wageningen University , Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Vincken
authors.affiliation: Laboratory of Food Chemistry, Wageningen University , Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
authors.forename: Harry
authors.initials: H
authors.lastname: Gruppen
authors.affiliation: Laboratory of Food Chemistry, Wageningen University , Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
authors.forename: Peter Alexander
authors.initials: PA
authors.lastname: Wierenga
mesh_terms: D000383:Agriculture / Q000379:methods; D000596:Amino Acids / Q000032:analysis; D027461:Beta vulgaris / Q000737:chemistry* / Q000502:physiology; D002241:Carbohydrates / Q000032:analysis; D004156:Catechol Oxidase / Q000378:metabolism; D002734:Chlorophyll / Q000032:analysis; D008055:Lipids / Q000032:analysis; D009426:Netherlands; D009584:Nitrogen / Q000032:analysis / Q000302:isolation & purification; D018515:Plant Leaves / Q000737:chemistry* / Q000502:physiology; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D013997:Time Factors
chemical_list: D000596:Amino Acids; D002241:Carbohydrates; D008055:Lipids; D010940:Plant Proteins; D002734:Chlorophyll; D004156:Catechol Oxidase; D009584:Nitrogen
keywords: Beta vulgaris L.; chemical composition; greenhouse study; phenolic compounds; polyphenol oxidase activity