4. Comparison of Oil Extraction Methods
The results from the mechanical and chemical extraction processes clearly indicate that the hexane
technique is superior in terms of producing higher oil yields. It was also observed that solvent extraction
is more repeatable, relative ease of preparation and no requirement for extensive training. However, seed
preparation has a significant impact on oil yields especially for the screw press extraction method.
Kernels prepared to 15% moisture content provided the highest oil yields for both extraction methods.
Although the oil extraction technique using the mechanical screw press was obtained at a low cost but this
is ineffective due to relatively lower oil yields. This process is relatively inexpensive after initial capital
costs. Moreover, this process is time consuming and labour intensive. On the other side, the chemical oil
extraction technique was found to be very effective because of high oil yield and for its consistence
performance but the lack of a hexane recovery system, it was not possible to take full advantage of the
effectiveness of the method. Moreover, this process is simple and quick, repeatable and reproducible
results. However, as evidenced by the bulk extraction results, the solvent extraction method proved to be
a vastly more time consuming and labour efficient process than mechanical process in the given
circumstances.