Enhancing the antioxidant content of carambola (Averrhoa carambola) during cold storage and methyl jasmonate treatments

Cold storage is commonly used to transport fruits to international markets, however, tropical fruits are susceptible to chilling injury. Jasmonic acid can reduce the incidence of chilling injury in tropical and subtropical fruit by application through spraying or dipping. The aim of this study was to assess effect of methyl jasmonate on the oxidative stress response of carambola (Averrhoa carambola), and consequently the quality of the fruit. Freshly harvested carambola were exposed to chilling storage at 6 degrees C and 60-70% relative humidity for 16 days, after treatment with methyl jasmonate (0.01, 0.1, 0.2 and 0.5 mM MeJA) or water alone as a control. Soluble solids content, titratable acidity, ascorbic acid, total phenolics content and antioxidant activity were assessed, along with PAL, POD and PPO enzymatic activity. MeJA application significantly repressed (P < 0.05) metabolic activity of the fruit. A significant increase in ascorbic acid (P < 0.05) was observed in the MeJA treated fruits however the antioxidant activity declined. MeJA mimics natural defense responses through different reactive oxygen species (ROS) scavenging mechanisms, allowing the accumulation of protective compounds. This accumulation was important because it enhanced the nutraceutical value of the fruit improving the international markets desirability of the fruit. Moreover, it allows the fruits to withstand cold storage, allowing transportation over long distances. (C) 2016 Elsevier B.V. All rights reserved.