The quince fruit is too hard to eat. It can be cooked to make it soft. Or it can be left out on purpose to rot a little which makes it soft. If it is damaged by frost, that helps start the process of making it soft and good to eat. Quinces are mainly used for making jelly and jam. The interior of a quince is white when it is raw, but it becomes pinkish orange when it is cooked, so that is the color of the jelly or jam when it is made.