Why do fruits continue to ripen when they're off the tree?

Question

You know, they can be green and sour, but a few days later they'll taste sweet and lovely. Why is that?

Answer 1

It actually the breakdown of complex sugar such as starch and saccharose into glucose and the accumulation of glucose. The complex surgar are stored during the eearly stage of the life of the fruit. If I remember correctly fruit usually do not photosynthesise. The fruit energy is only provided by the plant. when the fruit is harvested it starts to die and try to survive on its stored sugar