Abstract
Limes undergo internal metabolic changes during storage at ambient, resulting in rind disorders and green color fading that decrease consumer preferences and market demand. To elucidate the effects of exogenous 24-epibrassinolide (EBR) and chitosan (CT) treatments on the postharvest quality of citrus fruit, freshly harvested mature-green `Balady Banzahir' limes were dipped for 15 min in 20 mu M EBR and 1% CT alone or in combination and kept at ambient (23 +/- 1 degrees C and 60-70% RH) for 20 days. EBR or CT treatments retained fruit quality during shelf life as shown by higher green peel color (lower a* values), higher titratable acidity (TA) and lower weight loss, total soluble solids (TSS) and TSS/TA ratio compared to that of untreated control. Vitamin C content increased for 8 days in all treatments followed by a gradual decrease thereafter. Total flavonoid content (TFC) in peel increased reaching a peak on the 16.. day followed by a sharp decrease thereafter while, in pulp, it decreased with fluctuations. EBR or CT treatments retained higher vitamin C, and TFC contents in both peel and pulp. Antioxidant activity increased with fluctuations in both peel and pulp and was higher in treated fruit than the control. EBR or CT treatments showed higher peroxidase (POD) and lower PPO activities during shelf life than the control. Overall, postharvest dipping in 20 mu M EBR or 1% CT could be an effective treatment to retain quality of `Balady Banzahir' limes during 16 days of shelf life.