Studies on Egyptian cottonseeds: fatty acid-composition and protein patterns

Fourteen Egyptian cottonseed varieties were analysed to study some properties of their lipids and proteins. Lipid contents of the kernels ranged from 29.0 to 35.1%. The mean value of the iodine number was 110.9. The tested varieties showed little or no differences regarding to their fatty acid content. A slight higher proportion of linoleic acid was recorded for the triglycerides whereas the polar lipids components contained a lower amount of this fatty acids compared to that found in the total lipids. Protein contents in the examined varieties ranged from 32.3 to 37.9%. The amount of water-soluble protein ranged from 12.8 to 23.0% of the total protein. An almost complete recovery (94.5-100%) of the total protein was yielded when the extraction was performed with 0.02 N NaOH instead of water. The electrophoretic patterns of the water-soluble proteins gave only two bands, having a molecular weight between 14,000 and 25,000 dalton. A clear differentiation between the varieties was noticed when the alkaline soluble protein extracts were subjected to electrophoresis. Accordingly, the examined varieties were classified into five groups each of them having a similar spectrum.