title: Physicochemical and structural characteristics of rice starch modified by irradiation.
abstract: This work evaluated the physicochemical and structural properties of rice starch of the cultivars IAC 202 and IRGA 417 modified by irradiation. Starch samples were irradiated by (60)Co in doses 1, 2 and 5kGy, on a rate of 0.4kGy/h. A control not irradiated was used for comparison. The granule morphology and A-type X-ray diffraction pattern were not altered by irradiation. There was an increase in amylose content, carboxyl content and acidity with irradiation. Gamma radiation did not affect the thermal properties of IAC202, but increased gelatinization temperature of IRGA417, in the higher dose (5kGy). The number of long chains of amylopectin was reduced and short chains were increased for IAC202, whereas for IRGA 417, the opposite was observed, probably due to cross-linking of starch chains. Starches had their physicochemical and structural properties modified by irradiation differently.
authors.affiliation: Department of Food Engineering, Federal University of Rondônia, Av. Tancredo Neves, 3450, 76872-862 Ariquemes, RO, Brazil. Electronic address: lfpolesi@yahoo.com.br.
authors.forename: Luís Fernando
authors.initials: LF
authors.lastname: Polesi
authors.affiliation: Department of Agri-food Industry, Food and Nutrition, Luiz de Queiroz College of Agriculture, University of São Paulo, Av. Pádua Dias 11, CP 9, 13418-900 Piracicaba, SP, Brazil.
authors.forename: Silene Bruder Silveira
authors.initials: SB
authors.lastname: Sarmento
authors.affiliation: Department of Food Technology and Engineering, São Paulo State University (UNESP), R. Cristovão Colombo, 2265, 15054-000 São José do Rio Preto, SP, Brazil.
authors.forename: Jaqueline de
authors.initials: Jd
authors.lastname: Moraes
authors.affiliation: Department of Food Technology and Engineering, São Paulo State University (UNESP), R. Cristovão Colombo, 2265, 15054-000 São José do Rio Preto, SP, Brazil.
authors.forename: Célia Maria Landi
authors.initials: CM
authors.lastname: Franco
authors.affiliation: Department of Agri-food Industry, Food and Nutrition, Luiz de Queiroz College of Agriculture, University of São Paulo, Av. Pádua Dias 11, CP 9, 13418-900 Piracicaba, SP, Brazil.
authors.forename: Solange Guidolin
authors.initials: SG
authors.lastname: Canniatti-Brazaca
mesh_terms: D000687:Amylopectin / Q000737:chemistry; D000688:Amylose / Q000737:chemistry; D008970:Molecular Weight; D012275:Oryza / Q000737:chemistry*; D013213:Starch / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D013213:Starch; D000688:Amylose; D000687:Amylopectin
keywords: (60)Co; Amylopectin; Amylose; Chromatography; Gamma radiation; Oryza sativa