IRRADIATION OF DUNCAN GRAPEFRUIT, PINEAPPLE, AND VALENCIA ORANGES AND TEMPLES.

Abstract

Irradiation with dosages above 100 krad in duced some decay reduction in Pineapple and Valencia oranges stored at 70 F for 21 days without diphenyl pads. At 40 F there was less spoilage for the Temple fruit; with diphenyl pads and storage at 40 F there was less spoilage of Pineapple oranges. The citrus fruits exami ned showed irradiation induced peel injury. Tem ple fruit were the least susceptible to peel injury. The severity of peel injury was greater as the radiation doses increased or the storage temper ature and duration increased. Florida Agricultural Experiment Stations Journal Series No. 2543. lDepartment of Food Science, University of Florida, Gainesville. 2University of Florida Citrus Experiment Station, Lake Alfred. There were no differences in the organoleptic quality attributes of irradiated grapefruit stored 19 and 20 days at 65 and 58 F, respectively. No differences were observed in the color or consistency of juice expressed from irradiated Valencia oranges, but a lower flavor rating was obtained from the 300 krad level. Sections from Temple fruit irradiated with dosages in excess of 100 krad and stored 7 days at 35 and 50 F were softer and had less acceptable flavor. How ever, by extending the storage period to 13 days, no differences were observed in the flavor of Temples stored at 50 F. In view of the severity of peel injury irradia tion cannot be recommended for preservation of Florida citrus fruits. Introduction There is a widespread interest in the use of gamma radiation for the extension of shelf life of citrus fruits. While decay organisms can be inactivated by adequate dosages of gamma Table 1. Effects of irradiation, storage temperature and duration, and diphenyl on decay (%) and peel injury (points scale) in Duncan grapefruit.