The study of ionizing irradiation with Cobalt 60 (60Co), in this experiment, aimed to evaluate its influence on postharvest physical parameters for atemoia cv. ‘Thompson’, which are related to the fruit ripening process. The irradiation was carried out at the Radiation Technology Center -CTR IPEN / CNEN -SP, located in the university city USP (University of São Paulo) in the compact multi-purpose radiator where gamma rays are used. Atemias were irradiated with the following doses of cobalt 60 (60Co): T0 = No irradiation (control), T1 = 0.2kGy, T2 = 0.4kGy, T3 = 0.6kGy, T4 = 0.8kGy, T5 = 1,0kGy and T6 = 1,2kGy and then packed in expanded polystyrene trays (2 fruits / tray) and sealed with 0.020mm polyvinyl chloride films; exception made to the control treatment which did not receive irradiation; for each analysis parameter there were three repetitions with two fruits per repetition. The fruits under study were stored in a cold chamber at 15 ± 0.2ºC and 90 ± 2% RH. In all irradiation doses, the following analyzes were carried out: loss of fresh mass, soluble solids (SS), titratable acidity (AT), pH, ascorbic acid (AA), reducing sugars, respiratory rate. The analyzes were analyzed every three days (0,3,6,9,12,15 and 18) days of storage. The experiment was conducted in a completely randomized design (D.I.C.), in a factorial scheme (treatment x storage), composed of seven doses of gamma irradiation and seven storage times. The results were subjected to analysis of variance and the means compared by Tukey's test at the level of 5% probability and regression was performed for the analyzes in the storage period. This experiment can conclude that the doses of 1.0kGy and 1.2kGy demonstrate greater control of breathing, in atemoia, until the 9th day; three days more than the control treatment, the other parameters analyzed did not show any interference in the increase in postharvest life of the atemous cv ‘Thompson’.
