The outer skin is partially green when bananas are sold in food markets, and turns yellow when the fruit ripens. As it ripens the starches turn to sugar making a sweeter fruit. When it reaches its final stage, brown/black "sugar spots" develop. When overripe, the skin turns black and the flesh becomes mushy.
Bananas ripen naturally without being refrigerated, however by placing them in a refrigerator, the skin darkens quicker but they are kept from becoming soft and mushy for a longer period of time.
Ways to eat
The fruits of the Cavendish bananas are eaten raw, used in baking, fruit salads, fruit compotes and to complement foods.