Defatted Corn Protein Produces Palatable Gluten-Free Bread

A good, crusty roll with dinner is a pleasure most people take for granted. But for millions of Americans, this simple, basic pleasure is off limits because they cannot tolerate proteins found naturally in grains like wheat, barley, and rye that are used in flours.

Agricultural Research Service chemists Scott Bean and Tilman Schober, in the Grain Quality and Structure Research Unit in Manhattan, Kansas, had some success developing gluten-free pan bread from other grains, but they couldn’t make free-standing rolls because they spread out too much. “The bread was considered lower in quality than comparable wheat bread,” says Bean. Gluten-free grains include corn, sorghum, and rice.

Now Bean and Schober have found a way to make rolls from corn that are more than just gluten-free: they also rise more and resemble wheat rolls.

In previous studies, Bean and Schober found that a corn protein called “zein”—a readily available byproduct from corn wet milling and fuel-ethanol production—could be used to make a more wheatlike dough. The dough still didn’t meet their standards, though, because it lacked strength, and the rolls produced from it were too flat. They used a commercially available zein in that study.

But more recently, Bean and Schober found that by removing additional fat from zein, they were able to produce a dough more similar to wheat dough and free-standing hearth-type rolls that resemble wheat rolls. “We found that removing more of the fat from the protein’s surface allows the proteins to stick to each other much like wheat proteins do—leading to the elastic nature of wheat dough,” says Bean.

Even better than corn for baked products, according to Bean, is sorghum—a gluten-free grain of choice as a wheat substitute. But since corn and sorghum are similar, they used the former as a research model.

“Corn protein, in our view, is an intermediate step to achieving the Holy Grail of gluten-free breads—forming a wheatlike dough using nonwheat proteins, resulting in products with a fluffy, light texture,” says Bean.

This research may prove useful for the 2-3 million Americans affected by celiac disease, a condition in which the human immune system erroneously attacks the intestine when gluten is ingested, causing severe diarrhea and inability to absorb nutrients. Gluten-free palatable rolls from corn, rice, and sorghum would be a welcome addition to their diet.

A paper on this work was accepted by the Journal of Cereal Sciences.—By Sharon Durham, Agricultural Research Service Information Staff.

Scott Bean is in the USDA-ARS Grain Quality and Structure Research Unit, 1515 College Ave., Manhattan, KS 66502; (785) 776-2725.

"Defatted Corn Protein Produces Palatable Gluten-Free Bread" was published in the November/December 2010 issue of Agricultural Research magazine.