Effect of gaseous ozone treatment on mancozeb fungicide residue degradation and quality of 'Jinda' chili (Capsicum annuum L.) fruit during storage

Abstract

The mancozeb fungicide is commonly used to combat fungal diseases in a variety of fruits and vegetables. Unfortunately, its residues that remain present in fresh produce represent a threat to food safety and human health. Reducing toxic residues is urgently required. Using ozone fumigation treatment at concentration of 0, 15, 25 and 50 ppm for 30 or 60 min then stored at 25°C for 12 days, the reduction of mancozeb fungicide residues and fruit quality of 'Jinda' chili was determined. From this study ozone fumigation between 25 to 50 ppm for 30 or 60 min showed the effective treatment to remove the mancozeb residues by 47 to 62% according to GT-test Kit method and colorimetric analysis by spectrophotometer at absorbance 540 nm. The most effective treatment was found at concentration of 50 ppm for 30 min. Moreover, all ozonation treatment also delayed postharvest loss, reduced disease index and maintained the quality of chili by maintaining fruit firmness and lowering color development which are important parameters of chili marketing, indicated by delay in the decrease in hue angle values. The fruit color coincided with higher chlorophyll (Chl) content (Chl a and b) than that of control. Maintaining fruit quality after ozone exposure was accompanied by a decrease in ethylene production and respiration rate. These results suggest that ozone fumigation treatment at 50 ppm could be a useful and effective method to reduce mancozeb fungicide residues and maintain postharvest quality of 'Jinda' chili during storage at 25°C for 12 days.