Extension of Storage Life of Papayas Grown in Puerto Rico by Gamma Radiation Treatments

Shelf-life extension (measured as ripening delay) and the retention of nutrients in irradiated P. R. 965 papayas have been investigated at constant storage temperature and relative humidity. The major findings were: 1. The ripening process in irradiated papayas was delayed up to 7 days by the use of gamma radiation treatments. The maximum delay in ripening was achieved by 25 to 50 Krads treatments, while the 100 Krad treatment showed a slight stimulation of ripening in storage. 2. Some destruction of vitamin C (ascorbic acid) seemed to have been effected by the gamma irradiation, although there were only slight differences between dose levels. 3. The level of total carotenoids was not affected by gamma radiation. During storage, there was a marked increase in these pigments as the papayas ripened. 4. Gamma irradiation inhibited fungal proliferation on papaya fruit even at dosages of 25 Krad. 5. There was no effect observed at the dosages studied on the skin of the fruit which developed its characteristic bright yellow color when ripe.