Thermophysical properties, thermal diffusivity and specific heat of model solutions similar to juices were experimentally determined and the values obtained compared to those predicted by mathematical models (STATISTIC 6.0) and to values mentioned in the literature, according to the chemical composition. It was adopted a star planning to define the composition of the model solutions fixing the acid amount in 1.5% and varying water (82-98.5%), carboydrate (0-15%) and fat (0-1.5%). The specific heat was determined by Hwang & Hayakawa method and the thermal diffusivity was determined by Dickerson method. The results of each property were analysed by the response surface method. The results were significative, indicating that the models represented considerably the changes of thermal properties of juices according to their composition and temperature variations.
thermal diffusivity; specific heat; model solutions; juices
