Although I prefer using all-purpose flour in my pita bread recipe, sometimes I add whole wheat flour too. For example, try substituting 1/2 cup of wheat flour for 1/2 cup of white flour. Although I have never tried making 100% whole wheat pita bread, I have substituted as much as half of the white flour with wheat. The end result was still good, but not as good as white flour, in my opinion. Pita bread made with white flour is softer and more pliable.