The Rate-Independence of the Mixing of Wheat Flour Dough to Peak Dough Development

When examining quantitatively the material properties of wheat flour dough, the need arises to model the mixing of the dough in terms of some constitutive relationship which simulates the changing rheology of the dough during the mixing. In formulating a mathematical model of the mixing one key issue is the extent to which the mixing of the dough displays, at least with respect to certain mixers, rate-independent characteristics. Evidence is presented to support the hypothesis that, at least to first order, the evolving rheology, resulting from the mixing of a wheat flour dough in a Mixograph^TM, (but not necessarily in some other recording or commercial mixers), has a clear rate-independent character. When mixed on a variable speed 35 gm Mixograph^TM, flour water dough of constant moisture content, prepared from seven flours of widely differing protein contents, showed statistically significant differences in the number of mixer revolutions required to reach peak dough development and in their resistance at peak dough development. For each of the flours, the number of revolutions was essentially constant at the five different speeds examined, whereas the resistance increased gradually (and steadily) as the mixer speed increased.