Degradation of chlorophyll with or without synthesis of carotenoids is part of the ripening process in some fruits while other fruits like kiwi and avocado remains green.
Fruit that goes past its optimum ripeness enter senescence, a stage of overripeness and breakdown. The initiation of senescence is probably localized somewhere within the cytoplasm. Many of the conditions use to describe fruit senescence, such as color change that occurs when chloroplasts change to chromoplasts. In this stage, the texture loses its firmness, succulence is diminished, and sugar, acid, and aroma elements generally all decline in concentration.
Some fruits like the banana have an early senescence, and deterioration, once begun, is rapid. On the other hand, some fruit, like apples, resists the onset of senescence can be controlled by keeping the fruit at the lowest temperature that it can tolerate and by increasing the amount of atmospheric carbon dioxide to a control level. Too much carbon dioxide can be harmful.
For most fruit the optimum ripening temperature is between 15 and 25 °C independent of ripening behavior (climacteric-nonclimacteric) or sensitive to chilling injury.
Optimum ripening of fruit