Postharvest treatments with methyl salicylate and glycine betaine synergistically enhanced chilling tolerance and maintained bioactive compounds of blood orange fruit subjected to cold quarantine storage
Fariborz Habibi, Ali Sarkhosh, Fabián Guillén, Marı́a Serrano, Daniel Valero
Abstract
The effects of glycine betaine (GB) and methyl salicylate (MeSA) treatments, alone and in combination, on the chilling tolerance and bioactive compounds of blood orange cv. Moro during cold quarantine storage (2 °C for 60 days) were investigated. The fruits were treated with GB (15 and 30 mM) using vacuum infiltration at 30 kPa for 8 min and MeSA (100 μM) using vapor treatment for 18 h, along with a combination of both GB concentrations and MeSA. The treatment with 30 mM GB + 100 μM MeSA was the most effective. This treatment improved the fruit's chilling tolerance by enhancing antioxidant enzyme activity and osmoregulation, which maintained membrane integrity. Furthermore, it preserved organic acids (citric, ascorbic, malic, succinic, and oxalic acids), sugars (sucrose, glucose, and fructose), as well as total anthocyanins, total phenolics, and antioxidant activity by increasing phenylalanine ammonia-lyase activity and suppressing polyphenol oxidase activity. The combined MeSA and GB treatment had a synergistic effect in enhancing the cold tolerance of ‘Moro’ blood orange fruit during cold quarantine storage.