Evaluating viscosity of surimi paste at different moisture contents

The steady and dynamic shear viscosity of fish muscle protein paste obtained from Alaska pollock surimi at 95%, 90%, 85%, 80%, and 75% of moisture contents were measured in the temperature range of 5°C to 20°C. To estimate the steady shear viscosity at high shear rate from dynamic shear viscosity, the modified Cox-Merz rule was applied by introducing a frequency shift factor. The concentration dependence of zero-shear viscosity showed power-law dependence with an exponent of 3.5, and the universal behavior of viscosity at different protein concentrations was observed by a introducing reduced variables. The Carreau model was applied to describe the shear- thinning behavior of the surimi paste, and the model parameters estimated empirically showed moisture content dependence. The viscous flow behavior was independent of temperature (5°C to 20°C), and addition of starch decreased the flow index and viscosity of the paste, compared to the pure surimi paste.