title: Oxidation of amylose and amylopectin by hydroxyl radicals assessed by electrospray ionisation mass spectrometry.
abstract: The hydroxyl radicals (HO) are one of the most reactive oxygen species (ROS) involved in the oxidative damage of biological molecules, including carbohydrates. During the industrial processing of food, ROS can be formed. In order to identify the structural changes induced in starch by oxidation, amylose, amylopectin, and maltotriose, an oligosaccharide structurally related to these polysaccharides, were subjected to oxidation with HO generated under Fenton reaction conditions (Fe(2+)/H2O2). The oxidised polysaccharides were hydrolysed by α-amylase and the obtained oligosaccharides were fractionated by ligand-exchange/size-exclusion chromatography. Both acidic and neutral α-amylase resistant oligosaccharides were characterized by mass spectrometry. In oxidised neutral products, new keto, hydroxyl, and hydroperoxy moieties, and oxidative ring scission were observed at the reducing end of the oligosaccharides. The acid sugar residues occurred at the reducing end and included gluconic and glucuronic acid derivatives, and acids formed by oxidative ring scission, namely, arabinonic, erythronic, glyceric and glycolic acids.
authors.affiliation: QOPNA, Departamento de Química, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal. Electronic address: joana.simoes@ua.pt.
authors.forename: Joana
authors.initials: J
authors.lastname: Simões
authors.affiliation: QOPNA, Departamento de Química, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Ana S P
authors.initials: AS
authors.lastname: Moreira
authors.affiliation: QOPNA, Departamento de Química, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Elisabete
authors.initials: E
authors.lastname: da Costa
authors.affiliation: CICECO, Departamento de Química, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Evtyugin
authors.affiliation: QOPNA, Departamento de Química, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Domingues
authors.affiliation: Departamento de Química, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal.
authors.forename: Fernando M
authors.initials: FM
authors.lastname: Nunes
authors.affiliation: QOPNA, Departamento de Química, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Coimbra
authors.affiliation: QOPNA, Departamento de Química, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: M Rosário M
authors.initials: MR
authors.lastname: Domingues
mesh_terms: D000687:Amylopectin / Q000737:chemistry / Q000378:metabolism*; D000688:Amylose / Q000737:chemistry / Q000378:metabolism*; D017665:Hydroxyl Radical / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D017665:Hydroxyl Radical; D000688:Amylose; D000687:Amylopectin
keywords: Electrospray ionization mass spectrometry; Fenton reaction; Maltotriose; Starch