title: ESR investigation of starch gelatinization using novel spin probes.
abstract: The spin probes 1,1,3,3-tetramethylisoindolin-2-yloxyl (TMIO) and the sodium salt of its sulfonate, 1,1,3,3-tetramethylisoindolin-2-yloxyl-5-sulfonate (NaTMIOS) were used to monitor the microviscosity changes of water during starch gelatinization. In cereal starch, which contains mainly A-type polymorphs, evidence was found for the amylopectin and amylose regions, the latter undergoing a transition at about 55 degrees C and a large increase in the microviscosity on cooling. Pea starch contains both A-and B-type polymorphs and this was also found to have two domains and the 55 degrees C transition was observed for the amylose phase: the less mobile amylopectin showed a reversible decrease in water microviscosity on heating.
authors.affiliation: Food Materials Science, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK. jim.robertson@bbsrc.ac.uk
authors.forename: James A
authors.initials: JA
authors.lastname: Robertson
authors.forename: Leslie H
authors.initials: LH
authors.lastname: Sutcliffe
mesh_terms: D003497:Cyclic N-Oxides / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods; D005782:Gels / Q000737:chemistry*; D006358:Hot Temperature; D007211:Indoles / Q000737:chemistry*; D012212:Rheology; D013113:Spin Labels; D013213:Starch / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry*; D013696:Temperature; D014783:Viscosity; D014867:Water / Q000737:chemistry
chemical_list: C502049:1,1,3,3-tetramethylisoindolin-2-yloxy; C502050:1,1,3,3-tetramethylisoindolin-2-yloxy-5-sulfonate; D003497:Cyclic N-Oxides; D005782:Gels; D007211:Indoles; D013113:Spin Labels; D013451:Sulfonic Acids; D014867:Water; D013213:Starch