Damaged starch is produced during the dry milling process. It is caused by harder wheat kernels and finer grinds. Damaged starch exposes the internal amylose and amylopectin chains. This not only feeds the yeast in the dough, but also binds more water. When the yeast starts feeding on the available starch chains, the initial water bonded by these starch chains are released. This increases pan flow and reduces volume. It has shown to reduce bread loaf volume and increase crumb hardness1.
What is Damaged Starch?
It is a starch granule that is broken up into pieces. Not only does it increase water absorption and affect dough rheology, it increases food supply to the yeast and is more susceptible to fungal alpha amylase.2
Damaged starch is a by-product of milling wheat into flour. This is caused by the severity of grinding and the hardness of the wheat.
It increases water absorption and provides extra nutrition for the yeast. A high level of damaged starch would result in a sticky dough that produces a weak side wall and a sticky crumb (if enough amylolytic enzymes are available).
Use AACCI method 76-30.02 for determination of damaged starch.
Damaged starch level is generally at 2-4% for soft wheat flour, and 6-12% for hard wheat flour.3
1. Gabriela, Barrera, Perez Gabriela, Ribotta Pablo, and Leon Ribotta. “Influence of Damaged Starch on Cookie and Bread Making Quality.” European Food Research and Technology 225(2007):1.
2. Delcour, Jan A., and R. Carl. Hoseney. “Dry Milling” Principles of Cereal Science and Technology. St. Paul, MN: AACC International, 2010. 121-137.
3. Cauvain, Stanley P., and Clyde E. Stauffer. “Principles of Dough Formation” Technology of Breadmaking. New York: Springer, 2007. P306.