Bread-Bakers v112.n010.5

Very interesting post.

This supports the idea that one cannot judge a flour by protein 
content alone. The four proteins may not be in the same ratio.

For example, my understanding is that gliadins and glutenins tend to 
be more toward the center of the wheat kernel. Now keep in mind that 
whole wheat and high extraction flours tend to include more of the 
outer layers of the wheat. So a whole wheat flour may be listed as 
having a high protein percentage, but much of the increased protein 
level isn't the sort that is useful for bread structure.

Onward: Are you sure that vital wheat gluten is 100% protein? For 
example, King Arthur's vital wheat gluten lists a "serving" as being 
9 g, but having only 7 g of protein (and who knows how much of that 
is gluten?).

http://www.kingarthurflour.com/shop-img/labels/1298302076941.pdf

And I've see lower ratios on other brands.

Allen
SHB
San Francisco