Research Information System
FRUIT JUICES: PROPERTIES, CONSUMPTION AND NUTRITION, pp.183-253, 2009 (SCI-Expanded)
Viscosity of four fruit (pomegranate, pear, tangerine and lemon) juices have been measured at temperatures from 292 to 403 K and at pressures from 0.1 to 10 MPa for the concentrations from I I to 45 degrees Brix. The best and complete comprehensive compilations all of the available viscosity data for liquid foods at the present time are provided. The effect of temperature, pressure, and concentration on the viscosity fruit juices were studied. The measured values of the viscosity were used to calculate the temperature, (partial derivative ln eta / partial derivative T)(x), and concentration, (partial derivative ln eta / partial derivative x)(T), coefficients for the fruit juices. Various theoretical models (polynomials, power, exponential, logarithmic, and their various combinations) for the viscosity of fruit juices were stringently tested with new accurate measurements on pomegranate, pear, tangerine and lemon juices. The applicability, accuracy and predictive capability of the various models were studied. New models were developed to accurately represent the combined effect of temperature and concentration on the viscosity of the fruit juices. Models which represent the viscosity of fruit juices relative to pure water viscosity was considered. The empirical extension of the various theoretically based models for the viscosity of aqueous solutions to the fruit juices is considered. It was found that theoretically based models originally developed for the viscosity of aqueous system can be adopted with success for fruit juices. The average absolute deviation (AAD) between measured and calculated values from these models for the viscosity of fruit juices was within 0.8 % to 2 %. The values of the Arrhenius equation parameters (flow activation energy, E-a, and eta(0)) were calculated for the measured viscosities of pomegranate, pear, tangerine, and lemon juices as a function of concentration. The new viscosity models for the fruit juices are recommended for the future scientific and engineering used.