Relaxation phenomena of radicals induced in irradiated fresh papayas

Electron spin resonance spectrometry of the γ-irradiated fresh papayas followed by freeze-drying and powderization was performed. We found a strong single peak in the flesh was observed at g = 2.004 and attributed to organic free radicals. Using the method of Lund et al., relaxation times of the peak from 0 to 14 days-stored samples after γ-irradiation were calculated. T2 showed a dose response, while T1 kept almost constant by the increment of doses. The γ-radiation-induced radicals showing progressive saturation behaviors can be caused through a different pathway from indirect effects by the low LET radiations.