Subject: How is Vitamin C formed from unripe to ripe citrus fruits?

If a ripe orange is left for many days from the day it was plucked, 
the Vitamin C declines. Why? Also when Vitamin C oxidises, what does 
it form? 
In citrus fruits, does Vitamin C turn to glucose? Where does that 
Vitamin C get created (when going from an unripe to a ripe citrus 
fruit) and where does it dissapear to (ripe citrus fruit left for 
days) or becomes?

I hope my answers can be answered on a more molecular termed bases.

Re: How is Vitamin C formed from unripe to ripe citrus fruits?