title: Enzymatic browning and after-cooking darkening of Jerusalem artichoke tubers (Helianthus tuberosus L.).
abstract: Jerusalem artichoke tubers (Helianthus tuberosus L.) undergo enzymatic browning when peeled or cut, and turn grey after boiling, due to after-cooking darkening reactions between iron and phenolic acids. In an attempt to reveal the components responsible for these discolouration reactions, sensory evaluation and instrumental colour measurements were related to contents of total phenolics, phenolic acids, organic acids and iron in three varieties of raw and boiled Jerusalem artichoke tubers harvested in the autumn and the spring. No differences were found between varieties in sensory evaluated enzymatic browning, but Rema and Draga had higher scores than Mari in after-cooking darkening. Jerusalem artichoke tubers had higher contents of total phenolics, phenolic acids and citric acid in the autumn and low contents in the spring, while it was the opposite for malic acid. None of the chemical parameters investigated could explain the discolouration of the Jerusalem artichoke tubers.
authors.affiliation: Institute of Food Science, Aarhus University, Kirstinebjergvej 10, 5792 Aarslev, Denmark.
authors.forename: Vibe
authors.initials: V
authors.lastname: Bach
authors.forename: Sidsel
authors.initials: S
authors.lastname: Jensen
authors.forename: Morten R
authors.initials: MR
authors.lastname: Clausen
authors.forename: Hanne C
authors.initials: HC
authors.lastname: Bertram
authors.forename: Merete
authors.initials: M
authors.lastname: Edelenbos
mesh_terms: D000143:Acids / Q000032:analysis / Q000378:metabolism; D000328:Adult; D004156:Catechol Oxidase / Q000737:chemistry* / Q000378:metabolism; D003116:Color; D003296:Cooking / Q000379:methods; D005260:Female; D006368:Helianthus / Q000737:chemistry* / Q000201:enzymology / Q000254:growth & development; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D010636:Phenols / Q000032:analysis* / Q000378:metabolism; D010936:Plant Extracts / Q000032:analysis / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D035281:Plant Tubers / Q000737:chemistry* / Q000201:enzymology / Q000254:growth & development; D012621:Seasons; D013649:Taste
chemical_list: D000143:Acids; D010636:Phenols; D010936:Plant Extracts; D010940:Plant Proteins; D004156:Catechol Oxidase