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Cereal Chem 66:321-324   |  VIEW ARTICLE

Rheological Changes of Fortified Wheat and Corn Flour Doughs with Mixing Time.

L. L. Navickis. Copyright 1989 by the American Association of Cereal Chemists, Inc. 

Rheological properties of doughs blended from wheat and corn flours fortified with vital wheat gluten were measured on rested doughs for a series of mixing times (at increasing work energy inputs) all at the same water content. As mixing time increased, the volume of loaves baked from these doughs increased to a maximum, then decreased. The shear modulus obtained at small strains (0.2%) increased with mixing time, whereas the relaxation time generally decreased. The dynamic storage modulus G' increased with mixing time while the loss modulus G" decreased. The ratio G"/G' was close to 1.0 at the mixing time that gave the greatest loaf volume. This ratio (1.0) shifted to a longer mixing time at 1% higher water content. The response of these doughs to large torsional deformations was also examined. The maximum torque attained at first showed a stiffening dough, followed by less resistance as mixing time increased. The strain corresponding to the maximum torque generally decreased until the doughs were mixed well past the point of minimum mobility. A similarity is noted between maximum torque values and maximum strains of these blended flours and extensigraph measurements reported for all-wheat flours as influenced by mixing times.

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