Dose-dependent Effect of Ozone Fumigation on Physiological Characteristics, Ascorbic Acid Content and Disease Development on Bell Pepper (Capsicum annuum L.) During Storage

Ozone is a potent oxidizing agent which has the potential to extend fruit storage life by inhibiting disease development. Its oxidative action may also affect fruit quality. Fruit of bell pepper were exposed to 0 (control), 1, 3, 5, 7 and 9 ppm ozone at 12 A degrees C and 95 % relative humidity (RH) for 3 days, and their quality was monitored during an additional 24 days of storage at 12 A degrees C. Treatment with 7 and 9 ppm ozone significantly affected quality by enhancing fruit ripening as shown by higher rates of respiration and colour change and lower titratable acidity than that in untreated fruit. The treatments also increased membrane permeability, reduced firmness, enhanced weight loss and decreased ascorbic acid content of the fruit. Exposure to lower ozone concentrations (1 and 3 ppm) had no effect on fruit respiration, colour, titratable acidity and firmness. However, ascorbic acid concentration was increased. This could be due to the activation of fruit defence system that produces a high level of ascorbic acid to neutralize the oxidative activity caused by ozone. Fruit exposed to 3 ppm ozone were also rated by sensory evaluation as having better fruit flavour after 19 days of storage than that of fruit treated with 7 or 9 ppm ozone. Treatment of 3 ppm ozone also reduced anthracnose incidence. This shows that exposure to 3 ppm ozone has the potential to increase fruit ascorbic acid content, reduce disease incidence and maintain fruit physico-chemical quality.