PREDICTION OF THE NONLINEAR VISCOELASTIC PROPERTIES OF GLUTEN DOUGHS

The applicability of the Bird-Carreau model to gluten rheology was tes ted. Gluten doughs were prepared using a Brabender farinograph. Small amplitude oscillatory measurements were performed using the Rheometric s mechanical spectrometer (RMS-800) in the frequency range of 0.001 59 -15.92 92 s(-1). Steady shear measurements were conducted using RMS-80 0, Instron capillary rheometer and Rheometrics stress rheometer (RSR) in the shear rare range of 10(-5)-10(4) s(-1). Primary normal stress c oefficient (psi(1)) were obtained using slit rheometry and RMS-800. Th e empirical constants alpha(1), /lambda(1), alpha(2), lambda(2) and et a(0), necessary to simulate eta, psi(1), eta' and eta''/omega were obt ained from geometrical constructions composed of steady or dynamic dat a and were used as data sources to study the moisture effect at two te mperatures. The model was able to successfully predict the steady shea r viscosity eta, and small amplitude oscillatory properties eta' and e ta''/omega. However the experimental data for the primary normal stres s coefficient are smaller than the prediction.