Quality attributes limiting papaya postharvest life at chilling and non-chilling temperatures

Papayas were harvested in April and May, at color break ripeness stage and held at constant temperatures of 0, 5, 10, 15 or 20 degrees C in order to determine the quality attributes that limit marketability. Evaluations of weight loss, instrumental and visual color, flesh firmness, shriveling, chilling injury (Cl) symptoms, chemical composition, and decay were performed initially and every second day thereafter during 14 days of storage. Fruit stored at 0, 5 or 10 degrees C were transferred to 20 degrees C for 2 days at the end of storage to evaluate Cl symptom development. A significant ripeness stage difference between the harvests affected Cl susceptibility in that Cl symptoms developed faster and were more severe in the less ripe fruit. At 15 and 20 degrees C, papaya marketability was limited primarily by flesh softening, followed by color change indicative of over ripeness and by shriveling; at 0, 5, and 10 degrees C, marketability was limited by development of Cl symptoms and, to a lesser extent, by shriveling. Storage temperature had little effect on soluble solids, pH or titratable acidity. After 14 days at 0, 5 or 15 degrees C vitamin C content of papaya from the first harvest was reduced by 48, 36, and 42%, respectively. Papaya marketability in this study was not limited by decay except as a secondary manifestation of Cl following transfer to 20 degrees C after 2 weeks of storage at chilling temperatures. The quality curves constructed for each temperature showed that a single quality attribute cannot be used to express loss of quality of papayas over the range of temperatures evaluated.