Microwave Energy Effects on Quality of Some Seed Oils

Effects of microwave heating were investigated on chemical properties of seed oils in relation to tocopherol contents. For assessing quality of oils (linseed, soybean, corn, olive, and palm) during microwave treatments, peroxide, thiobarbituric acid, carbonyl and anisidine values were determined. As the amount of polyunsaturated fatty acids in oils increased the index for the chemical properties increased. After 8-10 min heating the amount of tocopherols decreased substantially in linseed, olive and palm oils, whereas that in corn and soybean oils was still ca. 90%. Thus, the reduction in tocopherols in oils is not necessarily in agreement with chemical properties of the oils.