Effect of continuous and intermittent heating of crude oils of some sunflower cultivars cultivated in Fayoum

ABSTRACT

The effect of continuous and intermittent heating of crude oils extracted from 5 sunflower cultivars cultivated in Fayoum; namely, Meiak, French, White, Striped and El-Kahira was studied. During continuous heating at 120C for 20 hours, the peroxide and thiobarbituric acid [TBA] values of oils gradually increased to reach their maximum after 10-18 hours and 16-20 hours, respectively, while at 150C they reached their maximum after 2-8 hours and 6-10 hours, respectively. Then, some decreases were recorded up to 20 hours of heating. Meanwhile, during intermittent static heating some physical and chemical changes of sunflower kernel oil occurred; hence, gradual increase in refractive index, viscosity, formation of polymeric materials, peroxide value and TBA, and gradual decrease in iodine value were recorded. On the basis of the obtained results, it was clear that Meiak and French cultivars gave lower acidity which makes them more promising to be used for oil production