Viscosity and physicochemical properties of cornelian cherry (Cornus mas L.) concentrate

Abstract

Rheological behaviour of cornelian cherry concentrate was measured using the rotational viscometer at different shear rates (0.55, 1.1, 2.2, 4.4, 8.8, 13.2, 17.6 and 22 s(- 1)), concentrations (30.8, 35.5, 39.6, and 44.2 degrees Brix) and temperatures (10, 20, 30, 40 and 50 degrees C). The experimental results showed that the cornelian cherry concentrate exhibited Newtonian behaviour in tested temperature ranges. The effect of concentration and temperature on apparent viscosity of cherry concentrate were found to be significant (P < 0.01). The effect of temperature on flow behaviour was defined by the Arrhenius relationship and the activation energy values ranged from 20 to 35.3 kJ/mol, which decreased with a decrease in the concentration. Three models (Exponential, Quadratic and Power Law) were investigated to describe the concentration dependency of viscosity. Among these models, quadratic model was found to describe well the experimental data. A mathematical equation was proposed for relationship among the concentration, temperature and viscosity.