Effects of electron-beam (E-beam) irradiation on the postharvest quality of ‘golden’ papayas

Brazilian papaya production and exports have increased in recent years, and as a phytosanitary requirement, emerging technologies have been introduced into the agricultural chain. Electron beam (E-beam) irradiation has phytosanitary potential for the treatment of fruits, as it is safe and effective in controlling agricultural pests, extending the shelf life of the fruits, and preserving their quality. E-beam irradiation doses of 1, 3, and 5 kGy were applied on 'Golden' papaya fruit, with non-irradiated fruits (0 kGy) used as a control were applied on 'Golden' papaya fruit inoculated with fungi Colletotrichum gloeosporioides and Phoma caricae-papayae to verify if this technology could reduce postharvest diseases from the papaya rot complex. Also, this study evaluated the effects of the same E-beam doses on the postharvest quality of papayas, by analyzing physicochemical characteristics such as titratable acidity (TA), total soluble solids (TSS), Total Phenolic Content (TPC), firmness, and weight loss, as well as enzymatic activity of pectin methylesterase (PME) and polygalacturonase (PG) in the fruit. E-beam irradiation did not affect these variables. A difference was observed among the tested doses on the TA, TSS, TPC, and weight loss with the temperature increase during storage. In the other analysis, PME and PG activity and firmness were not influenced by the irradiation doses. Fruit at the 1 kGy, in general, had similar results as the control ones, this dose also was effective in reducing the growth of C. gloeosporioides and P. caricae-papayae and maintaining the quality of fruit since the doses of 3 and 5 kGy caused injuries to them.