Extraction and Comparative Characterization of Oils from Edible Seeds of Glycine max and Sesamum indicum

Aim: The incidence of heart-related disease conditions due to consumption of cholesterol containing oils and the increasing global demand for oil for domestic and industrial purposes have necessitated the need for scientific evaluation of other neglected indigenous plants for potential quality oil yield. This study thus aimed at extracting and comparing physicochemical and nutritional properties of seed oils from Glycine max and Sesamum indicum with a view to diversifying alternative sources of oil to meet teeming industrial and health needs and for food security.

Methodology: Solvent extraction method was employed to extract oil from seed samples which were further subjected to estimation of physicochemical indices such as free fatty acid, saponification value, iodine value, peroxide value, specific gravity, refractive index, density, pH, melting temperature and viscosity according to methods described by using titration method.

Results: Findings indicated higher saponification (412.33 mgKOH/mg), acid (2.99 mgKOH/g), free fatty acid (1.49 mgKOH/g), viscosity (0.13 Pas) and melting point (5.66 oC) values for sesame seed oil than for soybean seed oil. However, soybean seed oil showed higher density (0.837 g/ml), specific gravity (0.842 Kg/m3), pH (6.21), iodine (47.25 wij’s or g/iodine/g) and peroxide (40.80 mEq/Kg) indices than that obtained for sesame seed oil though mean values were not significantly different.

Conclusion: From observed measured parameters, sesame seed may be suitable for industrial purposes such as the production of soap and paint owing to its high saponification, free fatty acid, viscosity and melting point values while soybean seed oil may be excellent source for domestic and nutritional consumption in addition to industrial use.