Because protein is an important component in any flour, we have included this information in each flour’s description. (The percentage will vary according to how the flour is processed.) Wheat flour has 6 to 13 percent protein. Like the flours, each starch behaves differently—they are not interchangeable. Most of these starches already will be familiar to you, and you’ll find that you use them in a variety of roles for both cooking and baking applications.