Effect of Chitosan and Green Tea on the Quality of Washington Navel Orange During Cold Storage

摘要

This study was carried out during two successive seasons 2012 and 2013 on Washington Navel orange. Fruits were dipped in 2% chitosan and/or 2% green tea either alone or in combination as a postharvest application to extend the ability of fruits to lowcold stress as the optimum quarantine when exports to foreign markets. Chitosan is considered as an ideal preservative coating to enhance the storage life of fresh fruits. It acts as an antifungal agent to control the postharvest fungal disease and forms a semi-permeable coating around plant tissues. Green tea was able to reduce chilling injury and skin browning in turn to increase the shelf life and marketability period. Fruits were stored at 0±2°C, 90-95% R.H for 60 days, then analyzed for physicaland chemical changes at 20 days intervals during storage period. Dipping fruits in chitosan alone was more effective in decreasing weight loss percentage. Besides, dipping with green tea alone delayed color transition compared to all treatments or untreated samples. Coating with chitosan + green tea was the best in reducing fruit decay, chilling injury, titratable acidity, losses percent of juice, activity of ascorbic acid oxidase (ASAO) and perooxidase (POX). On the other hand, the same treatment gavehigher values of soluble solids content, SSC/acid ratio and ascorbic acid content.