Abstract
•Effect of solvents used for the extraction.•Two castor plant varieties grown in Saudi Arabia.•Tocol and sterol contents were affected by the type and variety of the solvent.•Essential oils from leaves were characterized.
The choice of organic solvent plays an important role in the degree and nature of lipid extraction. This work aimed to first evaluate the effect of solvents (hexane an ethanol) used for the extraction of castor oils on their physicochemical properties and compositions. Second, the chemical compositions of the essential oils obtained from fresh and dried leaves of castor plants were studied by gas chromatography–mass spectroscopy analysis. Two castor plant varieties grown in Saudi Arabia (Ricinus communis zanzibariensis and Ricinus communis impala) were used in this study. The results showed that the tocol and sterol contents were significantly affected by the type and variety of the solvent. Moreover, the presence of minor fatty acids was related to the type of solvent. The ricinoleic acid and oil yields were not affected by the type of solvent but were affected by the variety. The chemical compositions of the essential oils obtained from fresh and dried leaves were characterized by high concentrations of fatty acid methyl esters (38.42%) in Ricinus communis zanzibariensis and ketone (29.67%) and aldehyde (24.77%) components in Ricinus communis impala. This work has proved that the quality of castor oils is related to the type of solvent extraction and the variety.