Extrusion May Help Flavor, Quality of Fiber-Enriched Dough

A researcher at Kansas State University, Manhattan, is using his expertise in extrusion processing to try to make bran-enriched flour more appealing for use in snack foods.

"The more fiber you add, the more the dough quality deteriorates," says Sajid Alavi, assistant professor of grain science and industry. "We're hoping this process will increase some of the properties of the flour. The foods might have a better physical quality."

Alavi and other researchers created flour enriched with varying levels of bran. They mixed the bran-enriched wheat flour with water using a standing mixer and let the dough sit overnight. The hydrated flour was then sent through an extrusion processor, which uses a series of rotating screws and heated barrels to precook the flour before it is pushed out of the end. After ropes of the dough came out, they were taken to a drying oven or a freeze dryer. According to Alavi, the freeze dryer produced higher-quality flour. Then, the dried ropes were ground back into flour for use in baking.

The researchers worked with the bakery science lab at the university to produce cookies and tortillas made with precooked, bran-enriched flour, as well as uncooked bran-enriched flour.

In subsequent sensory analyses, tasters reported liking cookies and tortillas enriched with bran flour, whether precooked or not. However, the precooked flour did have an increased level of soluble dietary fiber.