Postharvest melatonin treatment delays senescence and increases chilling tolerance in pineapple

Pineapple (Ananas comosus (L.) Merr.) is currently the third most important tropical fruit in world trade after banana and mango. Melatonin (MT) is found in different plant organs and tissues and is described as an endogenous elicitor with a signalling role that alleviates fruit chilling symptoms during postharvest storage. Melatonin effects on the overall quality of pineapple was investigated in fruit dipped in a 0.1 mM solution for 10 min and then stored at 9 °C for 21 days followed by 4 days at 22 °C. MT application delayed the over-ripening process in pineapple during storage. The respiration rate was reduced (∼ 47.76%) after 7 days of cold storage, and shell color and flesh firmness losses were delayed in treated fruit compared to untreated fruit. Flesh translucency and internal browning due to chilling injury were higher in untreated control versus treated fruit. This is the first study that showed the potential of MT fruit immersions to alleviating internal browning symptoms maintaining the external quality of pineapple during postharvest storage.