Combine flours in pasta machine bowl. Mix 1 minute, until blended.
Lightly beat egg whites together in a measuring cup. There should be 1/2 to 2/3 cup.
With pasta machine running, slowly add 1/2 cup of the egg whites over a period of about 3 minutes. Let machine continue to mix another minute. The dough should consist of lumps the size of peas and walnut halves. If it seems too dry, gradually add more egg white, 1/2 tbsp at a time. If it seems too wet, add more semolina flour, 1 tbsp at a time.
When the dough is the proper consistency, extrude according to the manufacturer's instructions.
Store pasta or cook immediately in boiling water 2 to 6 minutes.