Constitutive Analysis of the Nonlinear Shear Rheology of Flour Suspensions Obtained from Different botanical Sources

摘要

The evaluation and development of validated models for the nonlinear viscoelastic (VE) behavior of materials is an important area of research which has impact on a number of industrial processes including those in the food industry. Various nonlinear VE models have been developed over the years and evaluated for petroleum-based polymers; however, our understanding of the nonlinear VE behavior of biopolymers of industrial import lags our understanding of synthetic polymers. In the work reported herein, the nonlinear VE behavior of suspensions (20 percent by weight in deionized water) of defatted oat flour, oat bran, barley flour, and oat flour were investigated. The rheological properties were measured usig a Rheometrics Series iV controlled-strain rheometer equipped with a cone and plate fixture. The measurements were conducted at 23 +- 0.1 deg C. The rheological data were interpreted using a strain separable K-BKZ type (wagner) model. The K-BKZ model was found to provide an accurate description of the rheological behavior of the four flour suspensions.