The Impact of Methyl Jasmonate, Chitosan, and Storage Period on the Storability of Local Orange Fruits (Citrus sinensis L. Osbeck)

This study was carried out on fruit of local Diyala orange (Citrus sinensis L. Osbeck). The fruit were obtained from a private orchard in Buhriz village, Diyala governorate, Iraq, to study the impact of (control, 0.5, 1, and 1.5 mM) methyl jasmonate dipped for 3 min and chitosan (control, 1, 2, and 4% w/v) for 5 min on the fruit quality of orange in terms of (fruit weight loss (%), Total soluble solids (%), titratable acidity (%), ascorbic acid content, Total phenol content, chilling injury (%), decay (%), and catalase enzyme) during 30, 60, and 120 days storage at 5±1°C with 85-90% RH. Results showed that all treatments of (Methyl jasmonate and chitosan) significantly decreased the fruit weight loss (%). Furthermore, fruit treated with (1, and 1.5 mM) methyl jasmonate significantly reduced chilling injury (%), and decay (%), respectively, compared with the control. The titratable acidity (%), ascorbic acid content, total phenols, and enzyme catalase significantly increased in fruit treated with 0.5 mM methyl jasmonate compared to other treatments. On the other hand, the untreated fruits caused a significant increase in total soluble solids of both methyl jasmonate and chitosan compared with all other treatments. Dipping fruit in 2% chitosan effectively reduced chilling injury and decay compared with the control. There was a significant increase in ascorbic acid and total phenols when fruit were treated with (2, and 4%) chitosan, respectively. Consequently, all chitosan concentrations were superior to the untreated fruit in catalase activity. Prolonging the storage period from 30 to 60 and 120 days markedly increased the fruit weight loss (%), total soluble solids (%), chilling injury (%), and decay (%), while the titratable acidity (%), ascorbic acid content, and total phenol content substantially decreased. The interaction among both dipped treatments and storage period had a significantly positive influence on the quality parameters of orange fruit.