Since papayas do not contain much starch at the mature-green stage like bananas and mangos do, papayas do not increase in sugars content and associated sweetness after harvest. Exposure of mature-green papayas to 100 ppm ethylene for 1-2 days at 20°C and 85-95% relative humidity will accelerate loss of chlorophyll (green color) in the skin and softening of the flesh, but without increased sweetness. Thus, I do not recommend harvesting papayas at the mature-green to 25% ripe (yellow) stages and treating them with ethylene to degreen them. For better flavor and consumer satisfaction, I recommend that papayas be harvested at the 50% to 75% ripe (yellow) stage with at least 12% soluble solids content (as measured by a refractometer). In this case, there is no need to use ethylene treatment and postharvest life of these partially-ripe papayas can be extended by cooling them to 13°C soon after harvesting and transporting them at 13°C until they reach the retail display, where they can be kept at ambient store temperatures (20-25°C).

Please see our Produce Facts:  Recommendations for Maintaining Postharvest Quality of Papaya.

Additionally, you will find some additional helpful information, including bibliography resources, by typing "papaya" into the search field that appears at the bottom of each page of our web site: http://postharvest.ucdavis.edu.

-Adel A. Kader