title: Influence of heating time and pressure treatment of potato starch on the generation of radicals: EPR studies.
abstract: The influence of heating time and pressurizing time under pressure of 1 GPa on radicals generation in potato starch polymer was investigated by EPR. Potato starch was heated at two temperatures: 413 ± 2 K (140 °C) and 473 ± 2 K (200 °C) for 15, 30, 60, 120, 180, 240, 270 and 300 min and subdued to pressurizing under pressure of 1 ± 0.002 GPa for 6, 60, 300 and 1440 min. In starch heated at 413 K (140 °C) a decrease in the relative intensity of the EPR signal as a function of the pressurizing time can be observed, whereas in starch heated at 473 K (200 °C) such a decrease is not observed. The EPR spectra analysis indicates that they are powder spectra due to the paramagnetic centers leading to Lorentzian line shapes with weak spectroscopic splitting factor g anisotropies and linewidth anisotropies. We have shown that pressurization of starch causes a decrease in the number of radicals in a temperature range in which the polymer is not yet disintegrated. The results of the EPR investigations indicate the existence of a carbon radical center situated at the carbon C1 of the glucose ring. In the EPR spectra of the samples heated with no oxygen access, the hyperfine structure is poorly visible. In the registered EPR spectra of the samples heated with oxygen access, the hyperfine structure is not observed.
authors.affiliation: Institute of Molecular Physics of the Polish Academy of Sciences, ul. Mariana Smoluchowskiego 17, 60-179 Poznań, Poland.
authors.forename: Aldona
authors.initials: A
authors.lastname: Krupska
authors.affiliation: Institute of Physics, Faculty of Physics and Astronomy, University of Zielona Góra, ul. Prof. Zygmunta Szafrana 4a, 65-516 Zielona Góra, Poland.
authors.forename: Andrzej B
authors.initials: AB
authors.lastname: Więckowski
authors.affiliation: Faculty of Biological Sciences, University of Zielona Góra, ul. Prof. Zygmunta Szafrana 1, 65-516 Zielona Góra, Poland; Department of Food Concentrates and Starch Products, Institute of Agricultural and Food Biotechnology (Warsaw), ul. Starołęcka 40, 61-361 Poznań, Poland.
authors.forename: Lucyna
authors.initials: L
authors.lastname: Słomińska
authors.affiliation: Department of Food Concentrates and Starch Products, Institute of Agricultural and Food Biotechnology (Warsaw), ul. Starołęcka 40, 61-361 Poznań, Poland.
authors.forename: Leszek
authors.initials: L
authors.lastname: Jarosławski
authors.affiliation: Department of Food Concentrates and Starch Products, Institute of Agricultural and Food Biotechnology (Warsaw), ul. Starołęcka 40, 61-361 Poznań, Poland.
authors.forename: Roman
authors.initials: R
authors.lastname: Zielonka
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry*; D006358:Hot Temperature; D011312:Pressure; D011198:Solanum tuberosum; D013213:Starch / Q000737:chemistry*; D013997:Time Factors
chemical_list: D005609:Free Radicals; D013213:Starch