Effect of postharvest treatments and packaging type on shelf life and quality of local sour lemon (Citrus limon L.) fruits

Lemon is a nutritionally and commercially important Citrus fruit, yet it experiences considerable postharvest losses due to rapid quality deterioration during storage. Using environmentally friendly postharvest treatments has emerged as a practical approach for maintaining fruit quality and prolonging shelf life, offering safer alternatives to chemical-based preservation methods. Therefore, the present study aimed to extend the storage life of locally grown sour lemon fruits and preserve their physical and chemical attributes by applying eco-friendly treatments, while also determining the most suitable packaging type under these conditions. A storage experiment was conducted at the Postharvest Care and Storage Laboratory, College of Agricultural Engineering Sciences, University of Baghdad, from 20 October 2024 to 24 December 2024. The experiment followed a randomised complete block design (RCBD) with two factors and three replicates (2×7×3). The first factor involved packaging the fruits in foam trays and plastic trays, designated as F and B, respectively. The second factor consisted of immersing fruits for 5 minutes in the following solutions: distilled water (C), 10% and 15% gum Arabic (G1 and G2), 250 and 500 mL/L pomegranate peel extract (R1 and R2), and 0.5 and 1.0 mL/L eucalyptus oil (O1 and O2). The interaction between the two experimental factors demonstrated that combining plastic-tray packaging with immersion in 1 mL/L eucalyptus oil yielded the highest physical and chemical quality indicators in the fruits, both at the end of the storage period and following conditioning. This treatment reduced weight loss to 3.79% and 6.87%, maintained peel thickness at 2.49 and 2.33 mm, vitamin C at 43.00 and 40.33 mg/100 g fresh weight, acidity at 4.60% and 4.43%, chlorophyll content in the peel at the end of cold storage (0.78 mg/100 g), and total phenolic at 56.33 and 85.00mg/100 g fresh weight.