Dried papaya adds a tropical twist to trail mix, granola and fruit-nut bars. Begin with the best quality papaya you can buy or harvest. You'll have better results if you pre-treat the fruit with citric or ascorbic acid, which are available at supermarkets and drugstores. If you don't have a dehydrator, you can also dry the fruit in an oven. For best results, set wire cooling racks over cookie sheets for better air circulation.
Wash and peel each papaya. Slice the fruit in half lengthwise and scoop the seeds out of the papaya halves.
Turn the halves cut side down. Cut the papaya into lengthwise slices that are about 1/4- to 1/2-inch thick.
Stir 1 teaspoon citric acid, or 2½ tablespoons ascorbic acid, into a bowl containing 1 quart of water. Add the cut papaya and let the pieces soak for 10 minutes.
Drain the papaya in a colander.
Set your oven to its lowest possible temperature.
Arrange the drained papaya on wire racks set over cookie sheets, leaving plenty of space between the slices. Set the cookie sheets in the oven, and prop the oven door open 2 to 6 inches. If you're concerned about air circulation, set a fan near the oven door.
Begin checking the papaya after 12 hours. Remove the pieces when they still bend easily but most of the moisture is gone. This can take anywhere from 12 to 24 hours.
Pack the papaya pieces loosely into one or more containers. Put a lid on the top of each container, and set the containers in a dark, airy place. Leave the fruit for about one week, shaking the containers once or twice a day. This step, known as conditioning, allows any remaining moisture to be evenly distributed to all pieces of fruit, which helps prevent later spoilage.
Set the dehydrated papaya in tightly closed plastic bags or glass jars after they have finished conditioning. Keep the dried fruit in a dark cabinet.