Analiza zmian fizykochemicznych w wybranych olejach rafinowanych pod wpływem ogrzewania mikrofalowego o mocy 600 W
An Analysis of the Physicochemical Changes in Selected Refined Oils upon Heating to 600 W in a Microwave Reactor

Summary/Abstract: The aim of the study was to analyse qualitative changes occurring in selected Italian refined oils (Oleificio Zucchi) when heated to 600 W in a microwave. Sunflower, corn, soybean and peanut oils were studied. The oils were heated in a RM 800 microwave reactor. 50 g weight samples were heated for 6, 12, 18, 24 and 30 minutes. To evaluate the qualitative changes occurring in fresh and heated oils, quality indices determined according to PN/ISO standards were employed: peroxide, anisidine, acid and iodine values, and higher fatty acid content. Upon heating, the temperature of the oils rose to 187–215°C. The oxidative and hydrolytic changes that occurred were found based on the analysis of the anisidine, peroxide and acid value indices. The highest peroxide value (18 mEq O2 / kg) was observed for sunflower oil, while the rest had maximum values between 13.0 and 15.2 mEq O2 / kg. Maximum anisidine values in the investigated oils were 147.3 for soybean oil, 139.9 for corn oil, 133.2 for peanut oil and 124.7 for sunflower oil. In the fatty acid composition, a rise in the proportion of saturated fatty acid was found, above all, in palmitic acid. In the unsaturated fatty acid group, the changes occurred in oleic and linolic acids.

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