Variability of Electron Spin Resonance (ESR) signal of γ -irradiated starches
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2017
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INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE
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Resumo
Food preservation is one of the practical applications of radiation processing of materials. Starch is an abundant
and cheap nutritious biopolymer and also is the material for appropriate food systems and for technical
industries. Starch granules are partially crystalline structures composed mainly of two types of starch: amylose,
an essentially linear polymer, and amylopectin, with 3-44% of branch points. Electron spin resonance (ESR)
spectroscopy is a very powerful and sensitive method for the characterization of the electronic structures of
materials with unpaired electrons. The aim of the present work was to monitor the disappearance of the shortlife
and long-life free radicals formed during γ-irradiation of 3 different starches. Corn, potato and fermented
cassava starches were irradiated in a 60Co source Gammacell 220 with 20 kGy, dose rate around 1 kGy h-1. EPR
spectra were obtained at room temperature using a Bruker EMX plus model, X band equipment. The main type
of ESR signal from irradiated starch is a singlet with a g-value of about 2.0. The fading of ESR signals was
followed for 350 hours, and presents differences among the different starch type reflecting differences in
molecular arrangements of starch crystalline and amorphous fractions, although ESR spectra seemed to be
common for all starches.
Como referenciar
SILVA, GILBERTO D.; RODRIGUES JUNIOR, ORLANDO; DEL MASTRO, NELIDA L. Variability of Electron Spin Resonance (ESR) signal of γ -irradiated starches. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017. Disponível em: http://repositorio.ipen.br/handle/123456789/28217. Acesso em: 30 Dec 2025.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.