When bananas are peeled -- whether left whole or cut into pieces -- they begin to turn brown due to a process called oxidation. Although oxidation doesn't alter the flavour of the bananas, it can make them soft and unappealing. While sometimes brown bananas are ideal, as in the case of banana bread, most of the time slices that look, taste and have the texture of fresh bananas are most desired. Quick preventive measures can allow peeled bananas to retain their natural colour and flavour for four to five days.
Pour orange juice into a bowl. Make sure to fill approximately one-third of the bowl with the juice.
Place the peeled bananas in the orange juice. Add extra juice if necessary to ensure that they're completely covered. Allow the bananas to remain in the juice for one to two minutes to ensure that they are completely coated with the juice.
Transfer the bananas to a colander. Allow the orange juice to drain off of the bananas.
Lay two or three layers of paper towels on the countertop. Set the bananas on top of the paper towels and place another layer of paper towels over the bananas. Gently press the paper towels into the bananas to remove excess orange juice. It's important to remove as much liquid as possible so that the bananas don't become soggy and limp-looking.
Heat 1 qt. of water in a cooking pot. After bringing the water to a boil, allow it to cool completely.
Crush 500 mg of ascorbic acid in a mortar and pestle. Stir the ascorbic acid into the cooled water.
Place the peeled bananas in the ascorbic acid mixture and allow them to soak for one to two minutes. Drain in a colander to remove the excess moisture.
Place two to three paper towels on the countertop, one on top of another. Lay the bananas on top of the paper towels and cover them with more towels. Gently press the bananas between the layers of paper towels to dry them.
Substitute orange juice with lemon juice, pineapple juice or lime juice to prevent bananas from browning. Lemon and lime juice may add a sour flavour to the bananas, however. Slice or cut up bananas before soaking them in juice or ascorbic acid if the recipe you're using calls for sliced bananas. If extra juice will be added to a recipe calling for bananas -- in a fruit salad, say -- it's not necessary to dry the bananas before using them.