Oxidative enzymes and chilling injury and browning development in okra fruits

Resumo

In this study, okra fruits from cultivars Amarelinho and Mammoth Spineless were immersed in water at 40 °C at 15 and 30 minutes, the controls treatments were not immersed, followed by storage at 5 °C. It was done visual analysis of the fruits symptoms, total chlorophyll content and the concentration of phenolic compounds. Analyzed regarding the activity of catalase with the appearance of injury by cold and the relationship between activity of peroxidase and polyphenol with enzymatic browning. Regardless of cultivar, the fruits with higher storage period were those pre-immersed for 30 minutes at 40 °C. In all treatments, the cultivar Mammoth Spineless showed higher values of chlorophyll content compared to cultivar Amarelinho, which is intrinsic of this cultivar. The concentration of soluble phenolic compounds was higher for the cultivar Mammoth Spineless. For both cultivars, catalase activity was higher at the last days of storage regardless if the fruits immersed or not in hot water. The increased catalase activity coincided with increased symptoms of chilling injury. There was a positive correlation between polyphenol oxidase activity and the concentration of phenolic compounds with the fruit skin browning. As for the peroxidase activity, this relationship was not observed.