The effect of microwave heating on physicochemical properties of vegetable oils

In this paper, the effect of microwave heating on sunflower, soybean and peanut oils was studied. Each oil was heated for 2, 4, 6, 8, 10, 12, 15 and 18 minutes in microwave oven. Peroxide value, free acidity, colour absorbance, total tocopherols, conjugated diene and triene were measured. The results showed that the amount of peroxide value, colour absorbance and acidity were proportionally increasing with the increase of heating period. It was found that the total tocopherols of the microwave heated oils, decreased depending on the type of the predominating tocopherols. Also polyunsaturated fatty acids generally decreased by increasing the heating period.