Characterization and Comparison of Solvent Extracted and Traditional Mechanically Extracted Shea Butter

Abstract

Shea butter represents a very viable product for earning foreign exchange yet the potential of this abundant resource has not been adequately harnessed. This research compares the traditional mechanical extraction and solvent extraction methods of Shea butter using four different solvents namely ethanol, ethyl lactate, petroleum ether, and hexane. Fresh Shea nut was purchased from Kure market in Niger state and Shea butter was extracted from the nut using both traditional mechanical extraction and solvent extraction. Characterization of the extracted oil was done and the result showed the following chemical properties for solvent extraction method for the four solvents and traditional mechanical extraction respectively: acid value (6.72, 4.2, 8.96, 4.48, trace) mg KOH/g, free fatty acid (3.36, 2.1, 4.48, 2.24, trace) mg KOH/g, iodine number (6.36, 3.11, 5.43, 4.92, 5.36), peroxide value (9.30, 13.82, 10.99, 12.3, 14.13) meq O2/kg, saponification value (401.39,351.32, 348.18, 416.32, 419.13) mg KOH/g. Other physio-chemical properties quantified were moisture content (0.1062, 0.1215, 0.1086, 0.1064, 0.1380) %, density (0.880, 0.867, 0.879, 0.881,0.850), specific gravity (0.879, 0.894, 0.891, 0.894, 0.862), viscosity (88, 70, 69, 78, 80), melting point (32, 33, 34, 33, 34) OC, cloud point (34, 34 38, 34, 35)C, pour point (32, 31, 32, 31, 32) OC, flash point (249, 256, 250, 253, 255) OC, smoke point (219, 224, 217, 223, 223) OC for both solvent extraction and traditional mechanical method. The result obtained indicated that the most suitable method in terms of yield and moisture content was the solvent extraction method whereas the traditional mechanical extraction method had the advantage of low acid value and free fatty acid. It also showed that there was no significant difference in property using the four different solvents for extraction. Also both methods of extraction yielded shea butter with equally good physical and chemical properties that can compete favorably in the international market.