Postharvest Application of Chitosan and Low Temperature Storage Affect Respiration Rate and Quality of Plum Fruits

Application of edible coating as a way of prolonging the shelf-life of perishable fruits and vegetables is promising. Two plum cultivars (Stanley and Giant) were treated with 1% Chitosan and then stored at 0-1oC and relative humidity of 90±5% for 40 days. Changes in weight loss, respiration rate, fruit firmness, soluble solid content, titrable acidity, pH, ascorbic acid as well as decay rate were periodically recorded. The results indicated that Chitosan coating was effective in reducing weight loss, respiration rate as well as decay rate. A parallel trend in weight loss and decay rate was observed for both cultivars. Comparing the two cultivars, ‘Giant’ exhibited higher weight loss and respiration rate. Weight loss was mitigated through Chitosan application due to its positive effect in reducing respiration. In addition, Chitosan coating resulted in the retainment of a higher content of titrable acid, pH as well as firmness in either cultivar. However, total soluble solids and ascorbic acid contents were not significantly affected by the coating. The results finally indicated that Chitosan treatment is an effective strategy for maintaining organoleptic characteristics and as well for the prolonging of postharvest life in plums.