Postharvest effects of a chitosan-cinnamon essential oil coating on soursop fruits (Annona muricata L.)

In fruits, the postharvest application of edible films or coatings creates a barrier that helps regulate gas exchange – reducing both metabolism and transpiration as well as improving overall appearance and preservation. The objective of this work then, was to evaluate the effect of a chitosan-essential oil coating on the quality and postharvest life of soursop (Annona muricata L.). Chitosan-based coatings (Q) of two molecular weights (8 and 50 kDa) with or without cinnamon essential oil (CO) were applied to fruits at physiological maturity. After drying, they were held in refrigerated storage for 11 d (16°C, 90% RH), with additional controls kept under ambient conditions (20°C, RH 60%). The application of 8-kDa Q significantly increased respiration and did not influence the production of ethylene (P≤0.05). Additionally, various other parameters such as titratable acidity, total soluble solids, firmness, and the flavor index (TSS/TA ratio) were quite favorable, as was their overall appearance. Thus, the application of 8-kDa Q in combination with low temperature (16°C, 90% RH) notably increases the postharvest life of these fruits.