title: Protein insolubilization and thiol oxidation in sulfite-treated wheat gluten films during aging at various temperatures and relative humidities.
abstract: Gluten films were prepared by casting an acidic and ethanolic solution of gluten previously treated with sodium sulfite. The effects of sulfitolysis on proteins were investigated by SE-HPLC and thiol/disulfide content measurements. During sulfitolysis, insoluble glutenin macropolymer was converted into its constitutive subunits. About 10% of gluten disulfide bonds were cleaved, of which three-fourths originated from interchain disulfide bonds. Oxidation of thiol groups released during sulfitolysis was followed for various temperatures (T) and relative humidities. Oxidation was shown to be a second-order rate process occurring below the glass transition temperature (T(g)) and related to T - T(g). Thiol oxidation ensured the formation of interchain bonds between specific classes of gluten proteins according to an ordered process. Intrachain bonds were also formed and through thiol/disulfide-exchange reactions were finally converted to interchain bonds. Thus, fully oxidized gluten films had more insoluble glutenin macropolymers than native gluten.
authors.affiliation: Unité de Technologie des Céréales et des Agropolymères, ENSA.M - INRA, 2 place Viala, 34060 Montpellier Cedex 01, France. morel@ensam.inra.fr
authors.forename: M H
authors.initials: MH
authors.lastname: Morel
authors.forename: J
authors.initials: J
authors.lastname: Bonicel
authors.forename: V
authors.initials: V
authors.lastname: Micard
authors.forename: S
authors.initials: S
authors.lastname: Guilbert
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005983:Glutens / Q000737:chemistry*; D006813:Humidity; D010084:Oxidation-Reduction; D011506:Proteins / Q000378:metabolism*; D012995:Solubility; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D013447:Sulfites / Q000494:pharmacology*; D013696:Temperature; D013997:Time Factors; D014908:Triticum
chemical_list: D011506:Proteins; D013438:Sulfhydryl Compounds; D013447:Sulfites; D005983:Glutens