Papaya

MATURITY & QUALITY

Maturity Indices

• Change of skin color from dark-green to light-green with some yellow at the blossom end (color break). Papayas are usually harvested at color break to ¼ yellow for export or at ½ to ¾ yellow for local markets.
• Flesh color changes from green to yellow or red (depending on cultivar) as the papayas ripen.
• A minimum soluble solids of 11.5% is required by the Hawaiian grade standards.

Quality Indices

Papayas picked ¼ to full yellow taste better than those picked mature- green to ¼ yellow because they do not increase in sweetness after harvest.

Uniformity of size and color; firmness; freedom from defects such as sunburn, skin abrasions, pitting, insect injury, and blotchy coloration; freedom from decay.

TEMPERATURE & CONTROLLED ATMOSPHERE (CA)

Optimum Temperature

13°C (55°F) for mature-green to ¼ yellow papayas
10°C (50°F) for partially-ripe (¼ to ½ yellow) papayas
7°C (45°F) for ripe (>½ yellow) papayas

Optimum Relative Humidity

90-95%

Rates of Respiration

To calculate heat production multiply ml CO₂/kg·hr by 440 to get Btu/ton/day or by 122 to get kcal/metric ton/day.

Rates of Ethylene Production

Responses to Ethylene Production

Exposure to 100 ppm ethylene at 20 to 25°C (68 to 77°F) and 90-95% relative humidity for 24-48 hours results in faster and more uniform ripening (skin yellowing and flesh softening, but little or no improvement in flavor) of papayas picked at color break to ¼ yellow stage.

Responses to Controlled Atmospheres (CA)

Optimum CA 3-5% O₂ and 5-8% CO₂

Benefits of CA include delayed ripening and firmness retention.

Postharvest life potential at 13°C (55°F): 2-4 weeks in air and 3-5 weeks in CA, depending on cultivar and ripeness stage at harvest.

Exposure to O₂> levels below 2% and/or CO₂ levels above 8% should be avoided because of the potential for development of off-flavors and uneven ripening.