Oxidative degradation of sunflower oil blended with roasted sesame oil during heating at frying temperature

Abstract

The efficacy of roasted sesame oil (SO) on the oxidation deterioration of sunflower oil (SFO) during heating was investigated. The concentrations of SO in the SFO were 0, 10%, 20%, and 30% by volume. The oxidation profile of oil samples was monitored by evaluating the generation of oxidation products and chemical alterations in the oils' composition during heating at frying temperature (180 °C). The results showed that the oxidation parameters (free fatty acid, peroxide value, p-anisidine value, total oxidation status, thiobarbituric acid value, and color index) increased significantly in SFO compared to blends or SO during thermal treatment. During heating, the concentration of polyunsaturated fatty acids (PUFA) was reduced with increased level of saturated fatty acids; these results were observed more in SFO than those of SO or blend oils. However, the presence of SO in SFO reduced the decomposition of PUFA. In Fourier-transform infrared spectroscopy, the peak intensities were significantly altered in SFO compared to the blend oils during heating. Based on the most analytical data, it may be agreed that the heating at frying temperature led to the generation of relatively higher contents of oxidative products in SFO compared to blend oils, showing a lower degree of oxidation occurred in blends. The best frying performance for the SFO was achieved by using 30% SO extracted from the roasted sesame seed. This study showed the proper blending of high polyunsaturated oil with SO can produce oil blends with high nutritional values and enhanced stability for daily cooking and deep-frying applications.