Oil viscosity is typically measured and defined in two ways, either based on its absolute viscosity or its kinematic viscosity. There are also number of new vegetable oils such as grape seed, rice bran, macadamia nut, and many others. Ĭommon commercially-available vegetable oils are canola, corn, olive, peanut, soybean, sunflower, and others. The majority of the edible oils and fats produced worldwide annually is derived from plant sources and is referred as vegetable oils. Oils and fats are the essential materials for margarine, shortening, salad oil, and other specialty or tailored products, which have become significant ingredients in food preparation or processing in homes, restaurants, or food manufacturers. This means that greater energy was needed to effect a viscosity change in the peanut oil. The peanut and safflower oils had the highest and lowest activation energies, respectively. The activation energies for the different vegetable oils ranged from 21 to 30 kJ/mole. The absolute viscosities of the vegetable oils decreased with increasing temperature and can be fitted with an Arrhenius type relationship. The higher shear range used did not significantly affect the absolute viscosities of the vegetable oils at the different temperatures. s at 38☌) while walnut oil was the least viscous (0.0296 Pa.Rice bran oil was the most viscous (0.0398 Pa Based on the rheograms (plot of mean shear stress against shear rate), all of the vegetable oils studied were found to be Newtonian fluids. The torque of each sample at different temperatures was recorded at different shear rates. The absolute viscosities of the different vegetable oils were determined using a Lamy Viscometer RM100, a rotating viscometer with coaxial cylinder. A study was carried out to determine the effect of higher shear rates (64.5 to 4835 s −1) on the absolute viscosities of different vegetable oils at different temperatures (26 to 90☌).
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