Cereal Chem 59:529 - 533.  |  VIEW ARTICLE
High-Temperature Short-Time Extrusion Cooking of Wheat Starch and Flour. I. Effect of Moisture and Flour Type on Extrudate Properties.

J. M. Faubion and R. C. Hoseney. Copyright 1982 by the American Association of Cereal Chemists, Inc. 

The role of wheat flour components in the extrusion cooking of wheat starch and flour was assessed. Feed materials varying in water content and flour type were extruded and the products analyzed for texture, expansion, and ultrastructure. Increased initial moisture content decreased the expansion and weakened the texture of both starch and flour. Starch showed the greatest sensitivity to differences in moisture content. Analysis by scanning electron microscopy showed that extruded starch and extruded flour had complex but identifiably different ultrastructures. The most obvious difference noted was the presence in extruded flour of roughened cell walls with frequent failures. Hard (11% protein) and soft (9% protein) wheat-flour extrudates were similar in expansion and ultrastructure, whereas the extrudate of a high-protein (15%) flour differed in all three characteristics. Supplementing low-protein flours with their own or with high-protein gluten showed that differences among flours were due primarily to gluten quantity rather than to source.