Dear Adrian,
Three-year-olds can certainly be temperamental. It is more than likely that your daughter is displaying typical behavior, rather than anything of a worrisome sort.
Now, this does not mean you shouldn't address the behavior. It's one thing for her to reject the apple as you served it. If that were all, I would simply say it's there for her to eat or not, but I would not deliver another one. However, in light of the fact that she threw it, I would place her in time out for five minutes, telling her simply that throwing things is not allowed.
Dr. KDK