Abstract
The study evaluated the effect of postharvest UV-C radiation at 0.9, 2.8 and 4.9 kJ m(-2) on quality, antioxidant capacity, antioxidant compounds and enzyme activities of 'El-Bayadi' table grapes after 30 d of storage at 0 degrees C +/- 1 and 90-95% relative humidity (RH) plus 2 d of shelf life at 20 degrees C +/- 2 and 60-70% RH. UV-C radiation decreased decay and increased total soluble solids (TSS) concentration, while acidity, pH and firmness were not affected compared with the control treatment. UV-C treated grapes retained higher total phenols, total flavonoids and vitamin C concentration. Peroxidase and joolyphenoloxidase activities were higher in response to UV-C radiation, especially at 4.9 kJ m(-2). However, polygalacturonase and xylanase activities were lower, especially at 2.8 and 4.9 kJ m(-2) of UV-C radiation, compared with the control. Antioxidant capacity measured by both 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS) methods was not affected by UV-C radiation. UV-C radiation treatment (0.9-4.9 kJ m(-2)) decreased decay and retained quality of 'El-Bayadi' table grapes after storage and during shelf life.