Rheological and texture analysis methods for quantifying yield value and level of thixotropy

This study compares different methods for the assessment of yield stress and level of thixotropy in semisolid emulsions, using three instruments: an air-bearing controlled-stress rheometer, a T-bar viscometer and a texture analyser. The following methods were used to assess the yield stress: a low-rotation T-bar test, a shear stress sweep, a shear rate sweep, an oscillatory stress sweep and an immersion/de-immersion test on the texture analyser. The level of thixotropy was assessed by: a hysteresis loop test, a three-step thixotropy test and a repeated immersion/de-immersion test. It has been found that there was good correlation between the two rheological methods for detecting the level of thixotropy, the hysteresis loop and the three-step thixotropy test.