Modeling of rheological properties of cloudy apple juice using master curve

Abstract

The effect of temperature and concentration on the rheological behavior of pasteurized apple juice has been studied using a rotational rheometer at shear rates ranging from 0.5 to 12 s−1. The rheological properties were measured at different conditions changing from 10°C to 60°C and from 15°Brix to 40°Brix. On the basis of the obtained results, flow curves were prepared and consistency coefficients and flow indexes were determined. The superposition technique was applied to model behavior of apple juice. The obtained master curve is very important for the industry because it shows the apple juice in the whole range of temperature and soluble solid content. The influence of temperature on consistency coefficient was well described by the Arrhenius equation with activation energy values between 23.3 and 33.6 kJ⋅mol−1. A single equation was proposed for describing the combined effect of temperature, concentration, and shear rate on shear stress at constant flow behavior index. The model can be useful for the easy comparison of the rheological properties of different fluid food.