They are not viable without a male to fertilize them. The fact that she eats them is a normal action. Angelfish have a taste for their eggs even without the bacon, toast and coffee that would make breakfast complete. Once an angelfish has deposited her eggs and have been fertilized, they must be removed from the tank and raised separately. The male will fertilize after they have been deposited. If the male and female are not working together, you either have 2 females or a male that is not sexually mature.
Any eggs that turn white are not viable. They are also subject to fungus development quite readily. You will need to keep some methylene blue on-hand if you wish to raise the eggs. You can expect about a 50% success rate in the beginning.