title: Reaction pathways during oxidation of cereal β-glucans.
abstract: Oxidation of cereal β-glucans may affect their stability in food products. Generally, polysaccharides oxidise via different pathways leading to chain cleavage or formation of oxidised groups within the polymer chain. In this study, oxidation pathways of oat and barley β-glucans were assessed with different concentrations of hydrogen peroxide (H2O2) or ascorbic acid (Asc) with ferrous iron (Fe2+) as a catalyst. Degradation of β-glucans was evaluated using high performance size exclusion chromatography and formation of carbonyl groups using carbazole-9-carbonyloxyamine labelling. Furthermore, oxidative degradation of glucosyl residues was studied. Based on the results, the oxidation with Asc mainly resulted in glycosidic bond cleavage. With H2O2, both glycosidic bond cleavage and formation of carbonyl groups within the β-glucan chain was found. Moreover, H2O2oxidation led to production of formic acid, which was proposed to result from Ruff degradation where oxidised glucose (gluconic acid) is decarboxylated to form arabinose.
authors.affiliation: Department of Food and Environmental Sciences, Division of Food Technology, University of Helsinki, P.O. Box 66, FIN-00014, University of Helsinki, Finland. Electronic address: noora.makela@helsinki.fi.
authors.forename: Noora
authors.initials: N
authors.lastname: Mäkelä
authors.affiliation: Department of Food and Environmental Sciences, Division of Food Technology, University of Helsinki, P.O. Box 66, FIN-00014, University of Helsinki, Finland. Electronic address: tuula.sontag-strohm@helsinki.fi.
authors.forename: Tuula
authors.initials: T
authors.lastname: Sontag-Strohm
authors.affiliation: Department of Chemistry, Division of Chemistry of Renewables, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria. Electronic address: sonja.schiehser@boku.ac.at.
authors.forename: Sonja
authors.initials: S
authors.lastname: Schiehser
authors.affiliation: Department of Chemistry, Division of Chemistry of Renewables, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria. Electronic address: antje.potthast@boku.ac.at.
authors.forename: Antje
authors.initials: A
authors.lastname: Potthast
authors.affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FIN-02044 VTT, Finland. Electronic address: hannu.maaheimo@vtt.fi.
authors.forename: Hannu
authors.initials: H
authors.lastname: Maaheimo
authors.affiliation: Department of Food and Environmental Sciences, Division of Food Technology, University of Helsinki, P.O. Box 66, FIN-00014, University of Helsinki, Finland. Electronic address: henry.maina@helsinki.fi.
authors.forename: Ndegwa H
authors.initials: NH
authors.lastname: Maina
mesh_terms: D001205:Ascorbic Acid; D018554:Avena / Q000378:metabolism*; D002523:Edible Grain / Q000378:metabolism; D001467:Hordeum / Q000378:metabolism*; D006861:Hydrogen Peroxide; D010084:Oxidation-Reduction; D047071:beta-Glucans / Q000378:metabolism*
chemical_list: D047071:beta-Glucans; D006861:Hydrogen Peroxide; D001205:Ascorbic Acid
keywords: Ascorbic acid; Formic acid; Hydrogen peroxide; Oxidation; β-Glucan