Rheological properties of sour-cherry juice and concentrate

Rheological properties of sour cherry juice were determined by a Controlled Stress Rheometer. Sour cherry juice with different solid contents (40, 45, 50, 55, 60, 65, 68.5 and 70 Brix) was prepared using a rotary evaporator after squeezing and filtration of sour cherries. The rheological behavior of these concentrates was studied in the temperature range of 5, 10, 20, 30, 40, and 50°C. Sour cherry juice was found to exhibit Newtonian behavior. The effect of temperature on viscosity can be described by means of an Arrhenius equation. Activation energies appeared in the range of 22.44–73.49 kJ/mol with increasing concentration. To study effect of concentration on the viscosity, power‐law and exponential equations were used. Finally, two equation describing the combined effect of temperature and soluble solids content on the viscosity of concentrated sour cherry juice were obtained.