RESUMO
Some physiochemical properties of Meiak, French White, Striped and El-Kahira cultivars of sunflower oils grown in Fayoum were investigated. The weight of 1000 seeds, the hectoliter weight, kernel ratio, moisture content, ash content, crude oil, crude protein, crude fiber, refractive index at 25%, specific gravity at 25C, flow time at 30C, red color intensity, acidity, saponification value, iodine value, peroxide value, unsaponifiable matter% and thiobarbituric [TBA] value were determined. GLC technique was used for the identification of fatty acids and the unsaponifiable matter for such varieties. It was found that Meiak sunflower cultivar should be preferred for oil production; hence, it had the lowest moisture [3.57%] and highest oil percentage on dry basis [58.31%]. Moreover, its meal had a high protein content [29.27%]. However, as for oil stability it was found that French and Meiak attained the highest stability, being 13.00 and 12.00 hour at 100 degree, respectively
Assuntos
Sementes/químicaRESUMO
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