Biochemical Studies on Some Egyptian Plants and Its Relation to Environment

Abstract

This investigation are carried out to study effect of different doses of gamma radiation 0.5, 1.0, 2.0, 3.0, 5.0 and 7.5 KGy on chemical composition, protein, enzyme profile and lipid fractions of three cultivars of oil seeds soybean, peanut and sesame. The effect of gamma radiation doses on total protein solubility, albumin fraction, globulin fraction and SDS-ME fraction were investigated using SDS-PAGE of Laemmli (1970). The protein profiles and enzyme activities of; acid phosphatase, catalase, esterase, lipoxygenase, peroxidase and polyphenol oxidase were studied. Fatty acid and unsaponifiable profiles of oil seeds were qualitatively and quantitatively determined by gas- chromatography. The results showed that no significant changes in the chemical composition (ash, moisture, protein, carbohydrate, lipid and minerals content) in the three oil seeds in different treatments. The results of the electrophoretic separation of protein proved that protein profile of different protein fractions were affected by irradiation dose depending and on the cultivar. The solubility of total protein were decreased and reached to the maximum decrease using irradiation dose of 7.5 KGy compared to the control. The interesting phenomena are that albumin and globulin fractions decreased in its solubility while the SDS-ME increased. On the other hand the results of enzymes proved that, the activity of peroxidase and acid phosphatase were increased and reached to its maximum at 7.5 KGy while lipoxygenase and polyphenol oxidase activity were decreased with the increasing of y- irradiation doses in the three cultivars. The results of lipid contents proved that the ratios of total saturated fatty acids to unsaturated ones and total hydrocarbons to sterols were significantly altered upon irradiation. These changes were noticed in the lipid extracted from irradiated sesame seeds in comparison with the oils of irradiated peanuts and soybean. The maJor change in fatty acid composition was the decrease in the unsaturated fatty acids and the increase m the saturated fatty acids in all cases. In contrast, the cholesterol, campesterol, stigmasterol and P-sitosterol levels of irradiated seeds were generally lowered than that of the un-irradiated seeds. Key Words: Gamma irradiation, Chemical composition, Protein profile, Enzyme activities, Fatty acids, Hydrocarbons and Sterols.