 Pastry flour has the second-lowest gluten protein content, with 7.5-9.5% (8-9% from second source) protein to hold together with a bit more strength than cakes, but still produce flaky crusts rather than hard or crisp ones.All-purpose, or "AP flour", or plain flour is medium in gluten protein content at 9.5-11.5%(10-12% from second source) protein content.It has adequate protein content for many bread and pizza bases, though bread flour and special 00 grade Italian flour are often preferred for these purposes, respectively, especially by artisan bakers.