Delayed pericarp hardening of cold stored mangosteen (Garcinia mangostana L.) upon pre-treatment with the stress hormones methyl jasmonate and salicylic acid

Fruits are commonly subjected to cold storage, which can elicit negative changes in the fruit's physiology. This is more apparent in tropical fruits such as mangosteen, which experience pericarp hardening during chilling injury and senescence, due to diversion of phenolics content into increased lignin synthesis. The aim of this study was to explore treatments that may ameliorate the effects of cold storage on soluble phenolics content and fruit quality. Freshly harvested fruit were exposed to salicylic acid (SA) or methyl jasmonate (MJ) at one of five levels, and stored at 6 °C for 12 d. Physico-chemical quality attributes, total soluble phenolics content, polyphenol oxidase (PPO) activity and antioxidant activity were assessed. MJ significantly enhanced (P < 0.05) antioxidant activity and PPO activity, while delaying pericarp hardening. Fruit quality is closely linked to bioactivity, and can be dually enhanced by treatment with stress hormones.