Cereal Chem 58:370 - 374.  |  VIEW ARTICLE
Extrusion Cooking of a High-Fiber Cereal Product with Crispbread Character.

Y. Andersson, B. Hedlund, L. Jonsson, and S. Svensson. Copyright 1981 by the American Association of Cereal Chemists, Inc. 

High-fiber products with crispbread character were prepared by extrusion cooking of dry mixtures of wheat bran, secondary starch, and gluten in a twin-screw extruder. Product density decreased from 700 to 260 g/dm3 when the ratio between analyzed starch and dietary fiber contents was raised from 1.1:1.0 (a mixture of 50% bran, 40% secondary starch, and 10% gluten) to 4.1:1.0 (a mixture of 10% bran, 80% secondary starch, and 10% gluten). Increasing the screw speed resulted in a more expanded, less hard product, whereas changing the amount of added water had no effect. During extrusion, the total sugar content was reduced by 70-80%. Decreasing screw speed or addition of more water tended to increase the breakdown of glucose, whereas omitting gluten had the opposite effect. The phytate content, closely related to the bran level in the mixtures, decreased by 13-35%. A product with the character of Swedish crispbread in structure, texture, and taste was obtained when a mixture of 30% bran, 60% secondary starch, and 10% gluten was extruded. The extruded product contained only 6-7% water, and the amount of dietary fiber was calculated as 20.4%, which is about 75% more than the most fiber-rich crispbread varieties usually contain.