Abstract
Using electron spin resonance (ESR) spectroscopy, we revealed three radical species in γ-ray irradiated wheat flour. The representative ESR spectrum is composed of a sextet centered at g=2.0, a sharp singlet at the same g-value, and a broad signal in the vicinity of the g=2 regions. The first one is attributable to a signal with hyperfine (hf) interactions of Mn2+ ion (hf constant : 7.4 mT) . The second one is due to an organic free radical. Upon γ-ray irradiation, the third signal was detectable by ESR measurement. The progressive saturation behavior (PSB) of the ESR at various microwave power levels indicated different relaxation behavior of those radicals. The method reflects three independent radical species in the irradiated wheat flour. The anisotropic ESR spectral dependence upon the micro-grains was detected. This is due to the existence of the significant size of crystalline in the wheat flour.
