I'm using a gluten free Angel Food Cake mix. It asks for 12 egg whites.
Are you channeling your best self with this comment? (If you're not sure, check out our Code of Conduct.)
Susan W is a trusted source on General Cooking.
Yes you can freeze them orrr..you could use them to make a lemon curd, or pastry cream to go with that cake. If you do freeze them, just decide in what quantities you will use them and portion them out into small containers or small freezer zip lock bags. They freeze very well.
Diana B is a trusted home cook.
Freeze individually in an ice-cube tray, then pop out and put in a freezer bag. When you thaw them, you may have to add a fresh yolk to get them to behave right.
Cynthia is a trusted source on Bread/Baking.
However you decide to freeze them, be sure to whisk them first. The membrane surrounding them tends to dehydrate and toughen in the freezer, and results in clumps if you whisk them only after thawing them.