Selected Rheological Characteristics and Physicochemical Properties of Vegetable Oil Affected by Heating

Abstract

Estimating oxidative stability with successive heating temperatures provides a qualitative assessment of oil in the food industry. As one of the prime factors contributing to oil characteristics, the flow behavior of highly refined sesame oil and mustard oil were determined experimentally between the temperatures 25 and 85°C. The variation of viscosity with temperature was fitted in two variable empirical equations and the mathematical models were compared. Various physicochemical parameters of the oils like conductivity, density, viscosity, ultrasonic velocity, saponification value, iodine value, and free fatty acid content were observed to estimate their characteristics and stability on heating to cooking temperature. The physical and chemical parameters were compared and correlated between the oils to analyze the oxidative stability at different times of heating. A novel relation was demarcated between ultrasonic velocity and the chemical parameters. The study helped in the identification of the best oil suited for repeated cycles of heating.