Viscosity behavior of bitter orange (Citrus aurantium) juice as affected by temperature and concentration

The rheological properties of different concentrations (29.3–49.0°Brix) of bitter orange (Citrus aurantium) juice concentrate were evaluated using a viscometer at different temperatures (10–50°C). Samples showed Newtonian behavior. The effects of concentration and temperature on apparent viscosity of sample were significant (P < 0.01). Activation energy value (11.16–34.35 kJ/mol) increased with concentration. The exponential and quadratic models adequately described the effect of concentration on viscosity of bitter orange juice concentrate. To conclude, a single equation was proposed to show the combined effect of concentration and temperature.