title: Effect of γ-radiation on free radicals formation, structural changes and functional properties of wheat starch.
abstract: Wheat starch was treated by different γ-radiation doses (3, 5, 10, 20, 35 and 50 kGy). The effects of γ-radiation on structural, thermal, physicochemical, morphological and rheological properties of wheat starch were studied. The presence of free radicals after γ-radiation treatment, which number decreased with time was confirmed. Structural analysis revealed decreases in the intensities of the O-H and C-H stretches and glycosidic linkages indicating the depolymerization of amylose and probably amylopectin into shorter chain molecules, but showed that γ-radiation treatment did not affect the crystalline structure. Differential scanning calorimetric (DSC) thermograms showed the absence of significant differences in the gelatinization temperatures, as well as the corresponding transition enthalpies since the DSC parameters are related to the crystalline ordering within the granules. Apparent amylose content decreased linearly with increasing irradiation dose leading to an increase in water solubility index. An increase in the swelling power was observed after irradiation treatment until 20 kGy, followed by a rapid decrease at higher doses. Microscopic observations showed that the effect of γ-radiation was more visible on starch pastes than on starch granules. Rheological properties of the starch pastes decreased with increasing irradiation dose as a result of glycosidic bond cleavage.
authors.affiliation: Université de Carthage, ESIAT, Av. Alain Savary, Tunis, Tunisia; Université de Sfax, ENIS, LAVASA, BPW, 3038 Sfax, Tunisia.
authors.forename: Hager
authors.initials: H
authors.lastname: Atrous
authors.affiliation: CNSTN, Technopole de Sidi Thabet, 2020 Ariana, Tunisia.
authors.forename: Nasreddine
authors.initials: N
authors.lastname: Benbettaieb
authors.affiliation: CNSTN, Technopole de Sidi Thabet, 2020 Ariana, Tunisia.
authors.forename: Faouzi
authors.initials: F
authors.lastname: Hosni
authors.affiliation: Université de Liège, GxABT, Passage des Déportés 2, 5030 Gembloux, Belgium.
authors.forename: Sabine
authors.initials: S
authors.lastname: Danthine
authors.affiliation: Université de Liège, GxABT, Passage des Déportés 2, 5030 Gembloux, Belgium.
authors.forename: Christophe
authors.initials: C
authors.lastname: Blecker
authors.affiliation: Université de Sfax, ENIS, LAVASA, BPW, 3038 Sfax, Tunisia.
authors.forename: Hamadi
authors.initials: H
authors.lastname: Attia
authors.affiliation: Université de Sfax, ENIS, LAVASA, BPW, 3038 Sfax, Tunisia; Université de Carthage, INSAT, Centre Urbain Nord, B.P. 676, 1080 Tunis, Tunisia. Electronic address: Dorra.Ghorbel@insat.rnu.tn.
authors.forename: Dorra
authors.initials: D
authors.lastname: Ghorbel
mesh_terms: D000327:Adsorption; D000688:Amylose / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry*; D005720:Gamma Rays; D033081:Shear Strength; D012995:Solubility; D013213:Starch / Q000737:chemistry*; D014908:Triticum / Q000737:chemistry; D014783:Viscosity; D014961:X-Ray Diffraction
chemical_list: D005609:Free Radicals; D013213:Starch; D000688:Amylose
keywords: Free radicals; Wheat starch; γ-Radiation