Use of Ultraviolet Light to Preserve Quality and Control Postharvest Decay of 'Star Ruby' Grapefruit.

Star Ruby grapefruit harvested at three growing stages were subjcted to an ultraviolet - light ( UV-C, 254 nm) treatment by using three doses (0.5, 1.5 and 3 KJm-2). THe degree of pathogen ontrol following irratiation was shown to be mainly related to harvest time, while magnitude of UV-C dose resulted important for treatment damage. Moulds were reduced by 9% when 3 kJm-2 was applied on fully coloured fruit. Treatment damage on fully developed green skin fruit was evident only with 1.5and 3.0 kJm-2. At the breaker stage such damage occured at all doses while damage slandered on fully coloured fruit even at the highest UV-C dose. Phypaòexin induction for the same dose resulted lower in green compared to breaking and fully coloured fruit. Scopoletin resultedto be the major compound with antifungal activity induced by UV-C light at all harvest times. Weight loss was constantly higher in irradiated fruit and resulted the highest at the breaker stage. Organoleptic characteristics were not affected by the light treatment.