Characterisation of Moringa stenopetala seed oil variety "Marigat" from island Kokwa

Abstract

The oil from Moringa stenopetala seeds variety Marigat from the island Kokwa was extracted using 3 different procedures including cold press (CP), extraction with n-hexane and extraction with a mixture of chloroform:methanol (1:1) (CM). The yield of oil was 35.7% (CP) to 44.9% (CM). The density, refractive index, colour, smoke point, viscosity, acidity, saponification value, iodine value, fatty acid methyl esters, sterols, tocopherols (by high-performance liquid chromatography), peroxide value, E1cm 1% at 232 nm and the susceptibility to oxidation measured by the Rancimat method were determined. The oil was found to contain high levels of unsaturated fatty acids, especially oleic (up to 76.40%). The dominant saturated acids were behenic (up to 6.01%) and palmitic (up to 6.21%). The oil was also found to contain high levels of β-sitosterol (up to 52.19% of total sterols), stigmasterol (up to 16.53% of total sterols) and campesterol (up to 14.26% of total sterols). α, γ- and γ-tocopherols were detected up to levels of 98.00, 44.50 and 82.41 mg/kg of oil, respectively. The reduction of the induction period (at 120°C) of M. stenopetala seed oil ranged from 29.4% to 54.7% after degumming. The M. stenopetala seed oil showed high stability to oxidative rancidity. The results of all the above determinations were compared with those of a commercial virgin olive oil and Moringa oleifera seed oil.