Why do fruits become soft when ripe?

The cells of the raw fruit or vegetable are tightly packed and are held rigidly together by a carbohydrate called pectin which forms a strong bond with the walls of the coils and cements the cells together. As the fruit ripens, enzymes in the cells dissolve the pectin. When this happens the cells are no longer lightly bound to each other and the fruit becomes soft to the touch. Healing also dissolves the pectin. This is why vegetables and fruit become soft when cooked.