Application of Fundamental Dough-Mixing Parameters

Abstract

For a given flour quality profile, and formulation, there is a specific mixing intensity which should be imparted to the dough mass to ensure optimal dough development. Optimal dough development will result in the best possible dough viscosity, as a direct consequence of the attainment of the best compromise between the various processes of molecular build-up and breakdown which proceed simultaneously within the dough. The simplest method of achieving this is by adjustment of the mixing time, rather than by utilizing a fixed energy input. Specific mixing intensity in joules per kilogram per second (J k^-1 s^-1), is used as the integral parameter for the evaluation of the mixing process. Its value will depend upon the mixing speed, in rpm, and mixing time. The optimal specific mixing intensity is directly correlated with the effective dough viscosity measured at constant rate of shear. A convenient rate of shear for dough-effective viscosity measurements is 0.167 s^-1, at any chosen mixer-rpm. The most suitable type of viscometer for doughs is the rotation viscometer design, available from Brookfield (USA) and Haake (West Berlin), and the Rheotest 2, manufactured in the GDR by VEB Prüfgeräte. Shear rate ranges of 0.1 to 10 s^-1 are adequate for most dough viscosity measurements.