Cereal Chem 67:221-226   |  VIEW ARTICLE

Rheology of Low- to Intermediate-Moisture Whole Wheat Flour Doughs.

K. L. Mackey and R. Y. Ofoli. Copyright 1990 by the American Association of Cereal Chemists, Inc. 

A generalized model for predicting the viscosity of starch-based products was evaluated for whole wheat flour doughs at low to intermediate moisture content. The model incorporates the effects of shear rate, temperature, moisture content, time-temperature history, and strain history. An Instron capillary rheometer and a Baker Perkins MPF-50 D/25 corotating twin-screw food extruder was used to collect visocosity data. Die lengths of 6.35 x 10(-3) m and 2.54 x 10(-2) m, with diameters of 3.18 x 10(-3) m and 1.59 x 10(-3) m were used in the capillary rheometer. Extruder dies of 6.35 x 10(-3) m diameter, and 2.54 x 10(-2) m and 3.18 10(-3) m lengths were used. Whole wheat flour dough viscosities were evaluated at moisture contents of 0.333, 0.337, 0.385, and 0.436 g water per gram of starch, dry basis, in capillary rheometer tests. Barrel temperatures in the capillary rheometer were maintained at 50, 55, 60, 75, 85, 95, and 110 C over cook times of 1, 2, 3, 6, 12, and 24 min. Overall, the accuracy of rheological modeling for whole wheat flour was not nearly as good as had been observed in previous studies on corn starch and potato flour. This lack of accuracy may be attributed to the presence of flour components such as bran, protein, and lipids, which the model does not account for and which most probably altered the starch gelatinization kinetics.