A Review of Methods Used for Seed Oil Extraction

Seed oils have found application as food (edible oil), and generally as raw materials for the synthesis of biobased polyols, polymers, resins, fuels, soaps and detergents, lubricants and other products of the chemical industry. Consequently, a lot of attention is being paid to these biodegradable, renewable bioresources of plant origin as potential candidates for the replacement of costly and environmentally unsafe chemical feedstock of fossil origin. Oilseeds represent a green or natural reservoir from which these resources can be harnessed and utilized as platform chemicals at laboratory and industrial scales on a sustainable basis. In this review, old traditional methods, well-known and widely practiced conventional methods, and new, innovative methods of seed oil extraction are brought to focus and compared in terms of oil yield and oil recovery, as well as oil purity and quality. The merits and demerits of these methods are highlighted. More importantly, process control measures towards raising and optimizing oil yield and improving oil quality are discussed. Literature review and analysis has shown that oilseed pretreatment prior to oil extraction is a very important step towards achieving good oil yield and quality. Ultimately, the selection of suitable extraction method (s) may also depend on whether small or large scale oil extraction is intended. It is hoped that this review would be useful to stakeholders in seed oil prospecting and exploitation, notably oilseed researchers and oilseed processors, in selecting the most suitable methods of oil extraction.