EFFECT OF TEMPERATURE AND CONCENTRATION ON RHEOLOGICAL PROPERTIES OF FOOD PASTES

Abstract

Rheological properties of tomato paste were investigated using rotational viscometer at different temperatures (30, 40, 50, 60, 70 and 80°C) and at different solid concentration of 5, 10, 15, 20 and 23 % total solid. The results showed that all samples exhibited non-Newtonian pseudoplastic behaviour and fitted well to the power law model. The effect of concentration on the apparent viscosity of tomato paste was fitted well to power law equation , as the apparent viscosity increased with the increasing of concentration of tomato paste at all temperatures studied. The effect of temperature on the apparent viscosity of tomato paste was fitted well to Arrhenius law. The activation energy was found in the range of 8.31–90.7 kJ/mol.

Key Words: Rheological properties; Viscosity; Tomato paste; Activation energy; Food pastes.