title: The influence of the starch component on thermal radical generation in flours.
abstract: Transition metal ions and radicals in flours of various botanical origins with different content of starch have been studied by EPR before and after thermal treatment. The amounts of metal ions, have been determined by ICP OES. Simulations of EPR spectra have revealed the presence of several types of radicals (carbon-centred, tyrosyl and semiquinone) localized in starch and protein fractions of flours. Thermal treatment of flours significantly increased the amount of radicals with a simultaneous decrease of the signal intensity of transition metal ions. The proposed mechanism of thermal generation of stable organic radicals was associated with the redox processes involving transition metal ions, which facilitated the formation of radicals. The dependence between the way starch is treated and the mechanism of radical formation was also shown.
authors.affiliation: Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland. Electronic address: labanows@chemia.uj.edu.pl.
authors.forename: Maria
authors.initials: M
authors.lastname: Labanowska
authors.forename: Magdalena
authors.initials: M
authors.lastname: Kurdziel
authors.forename: Maria
authors.initials: M
authors.lastname: Filek
authors.forename: Stanisław
authors.initials: S
authors.lastname: Walas
authors.forename: Anna
authors.initials: A
authors.lastname: Tobiasz
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Wesełucha-Birczyńska
mesh_terms: D005433:Flour; D005609:Free Radicals / Q000737:chemistry; D013213:Starch / Q000737:chemistry*; D013696:Temperature; D028561:Transition Elements / Q000737:chemistry
chemical_list: D005609:Free Radicals; D028561:Transition Elements; D013213:Starch
keywords: Carbon-centred radicals; Cereal flours; EPR; Transition metal ions; Tuber flours; Tyrosyl radical