especially during summer.
as for egg whites not mixing into protein shakes, why not just add some whey protein in the protein shake, and cook up a nice egg-white omelette later on? Safer and tastes better! What I use for a protein shake is a bit of skim milk and whey protein. sure there's some carbs in the milk, but i use a small amount and anyway i heard it is easier for the body to absorb protein if it's mixed in with some carbs or fat.
but i have heard that egg beaters mix in well with anything.