Aqueous enzymatic extraction: A green, environmentally friendly and sustainable oil extraction technology

The adverse environmental impacts of conventional oil processing technologies have forced the development of new green technologies. The aqueous enzymatic extraction (AEE) destroys the oilseed through enzymatic hydrolysis and separates the oil and hydrophilic components with water, to achieve simultaneous separation of oil and protein etc. With no solvent residue, environmental pollution and safety issues, and mild processing conditions, AEE is recognized as an ideal green technology for oil extraction. This review discusses the entire process and research progress of AEE in oil extraction, from the oilseed pretreatment to the final crude oil. The two barriers to oil release (cell wall, oil body), the selection basis of enzyme, the influencing factors of AEE, and the combination of demulsification technologies to achieve efficient oil extraction were analyzed. The selection of enzymes depends on the cell wall, oil body composition and structure of the oilseed, and extraction of oil can be achieved through the use of single or mixed enzymes. In combination with ultrasound, microwave and pulsed electric field assisted techniques, the extraction efficiency can be improved. To the emulsion formed by the extraction, high oil yield was achieved by analyzing the emulsification composition and corresponding demulsification treatments. Moreover, the quality, micronutrients and oxidative stability of oil extracted by AEE are effectively improved compared with traditional technologies. The immobilization of enzymes increases the possibility of industrialization of AEE.