| Abstract: |
The proximate chemical analysis of Moringa oleifera seed was studied. The mature seeds contained 7.4% moisture, 30.11% crude oil, 27.64% crude protein, 19.93% carbohydrates, 6.2% ash and 8.72% Crude fiber. The effect of the extraction technology as well as the degumming process on the percentage oil recovery as well as the properties of oil and remained meal of Moringa oleifera seed has been thoroughly investigated. The methods used for oil extraction were solvent extraction using commercial hexane, aqueous enzymatic extraction and extraction by hydraulic press. The oil obtained in each case as well as the degummed oil was tested for all important physical and chemical properties such as the color, oil content of α-, γ- and δ-tocopherols, oil oxidative stability .. etc. Biological evaluation of the oils extracted by each method as well as the degummed oil samples has been also done and compared to sunflower oil. Histopathological examination has been also carried out.The results have shown that the percentage oil recovery was highest by extraction using commercial hexane. Therefore, the process of oil recovery by solvent extraction has been studied more extensively. The effect of solvent- to- solid ratio ,number of extraction stages ,extraction period and stirring speed on the percentage of oil recovery has been investigated. The results have shown that the most controlling variables were the solvent-to-solid ratio as well as the number of extraction stages. The composition of the solvent rich phase (overflow phase)as well as that of the solid rich phase (underflow phase) has been determined at equilibrium . Based on the data obtained, the locusof both phases at equilibrium has been established which can be used for the graphical determination of the number of theoretical extraction stages required to achieve a certain percentage of oil recovery upon industrial application where the process occurs in a continuous counter-current pattern. It has been applied in the present work for the estimation of necessary number of theoretical extraction stages needed to achieve a desirable extraction efficiency using solvent to solid ratio equivalent to 5/1.Regarding the effect of the extraction method and the process of crude oil degumming on the oil properties ,the results have proved that aqueous enzymatic extraction gave the lightest colored oil. However, it contained the least amount of δ-tocopherol compared to those extracted by the other two methods of extraction. This has been reflected on the oil oxidative stability ,being lowest in case of the oil obtained by enzymatic extraction . Similarly ,It has been also proved that oil degumming improved the oil color but it reduced the oil content of δ-tocopherol. Consequently, it reduced its oxidative stability.
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