In 1994 I was diagnosed with celiac disease, which led me to create Celiac.com in 1995. I created this site for a single purpose: To help as many people as possible with celiac disease get diagnosed so they can begin to live happy, healthy gluten-free lives. Celiac.com was the first site on the Internet dedicated solely to celiac disease. In 1998 I created The Gluten-Free Mall, Your Special Diet Superstore!, and I am the co-author of the book Cereal Killers, and founder and publisher of Journal of Gluten Sensitivity.
Most of the wheat grain and of white flour is made up of starch granules. Starch granules make up about 75% of grain or of white flour. In the processes used to make wheat starch, a small amount of the gluten protein (actually mostly the gliadin fraction, but not entirely), sticks to the surface of the starch granules. The amount depends on the washing method, how many times the granules are washed, and factors like that. Wheat starch can be made very low in surface protein and it is only the surface protein that is of concern (there are some internal granule proteins, but we are pretty sure that they are not gluten proteins).
For more information on Codex wheat starch visit the Codex Wheat Starch page.