An ESR study on identification of gamma-irradiated kiwi, papaya and tomatousing fruit pulp

In this work we use paramagnetic defects induced by radiation in the fruit pulp to identify gamma-irradiated kiwi, papaya and tomato. Pulp without see d, peels or stalks are treated by alcoholic extraction in order to remove w ater, soluble fractions and solid residue. The ESR spectra of pulp samples of irradiated fruit is composed of species A (g = 2.0045) and species C (g = 2.0201 and g = 1.9851.), which are also observed in irradiated stalks and skins. In comparison with samples which are not submitted to alcoholic ext raction, species C is stable enough to be used as a dose marker. Furthermor e, the species C signal can be detected perfectly even in pulp samples irra diated with doses as low as 200 Gy. Irradiation doses of fruit, exposed to 200-900 Gy of a gamma rays, were estimated with an overall uncertainty of 1 5% using dried pulp samples. These results indicate that radicals induced i n pulp have potential to be used in the identification and absorbed dose de termination of irradiated fruit.