A Comparative Study of the Extraction and Characterisation of Oils from Glycine max L. (Soya Bean Seed), Elaeis guineensis (Palm Kernel Seed) and Cocos nucifera (Coconut) Using Ethanol and n-Hexane

Aims: To extract and characterize oils from Glycine max L. (soya bean seed), Elaeis guineensis (palm kernel seed) and Cocos nucifera (coconut) using ethanol and n-Hexane.

Place and Duration of Study: Department of Industrial Chemistry, Renaissance University, Ugbawka, between December 2017 and July 2018.

Methodology: Using Soxhlet extraction method, the milled seed samples (soya bean, coconut and palm kernel) were bagged and extracted with accurately measured quantity of each solvent (n-Hexane and Ethanol). Physicochemical analysis which includes: Acid values, iodine value, free fatty acid (% oleic) and saponification value was carried out on the extracted oil.

Results: The percentage oil yield from ethanol extracts were 8.58% (8.58 g), 26.01% (26.01 g) and 31.21% (31.21 g) for soya bean, coconut and palm kernel respectively while that of n-Hexane extracts were 14.69% (14.69 g), 31.85% (31.85 g) and 45.28% (45.28 g), due to the fact that 100 g of the milled sample was used. Free fatty acid values were the same in n-Hexane and ethanol extracts of soya bean oil. These values were slightly higher in the coconut and palm kernel oil extracts using ethanol. Acid values were observed to be slightly higher in the ethanol extracted oils. The Saponification values were generally higher in ethanol extracted oils than in hexane extracted oils. There was maximum oil recovered with hexane than ethanol when the extraction process was carried out for 120 minutes.

Conclusion: In spite of the fact that n-Hexane gave a better extraction yield, ethanol appeared to be a better alternative for the extraction process because it is green, less toxic and safer to handle.