Abstract
A theoretical model was developed for predicting effects of temperature-time history, temperature, shear rate and moisture content on apparent viscosity of heated-denaturing defatted soy flour dough. The model was developed for stationary conditions and hence shear rate-time history effects were not included. Experimental studies were conducted using a capillary viscometer. Viscosity data obtained for various operating conditions were used to evaluate model parameters. Certain parameter values were compared with those reported in the literature. Several extrudate properties (moisture loss, bulk density, swell ratio, rehydration capacity and texture) were measured and correlated with operating conditions and viscosity. The theoretical model predicted reasonably well the effects of temperature-time history, temperature, shear rate and moisture content on apparent viscosity for three decades of viscosity (100-100,000 Pa-sec). An integral temperature-time history function was developed for incorporating the effects of variable temperature-time distributions. The integral history function can be used for predicting the extent of protein texturization for given temperature-time distributions. Model parameters evaluated in this study were found to have excellent agreement with values found in the literature. The theoretical viscosity model was also used successfully to predict variable effects on extrudate (extruded sample) texture.
Morgan, Ronnie Glen (1979). Modeling the effects of temperature-time history, terperature, shear rate and moisture on viscosity of defatted soy flour dough. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -187886.