Until recently, extraction of oil from oilseeds was performed using conventional methods via solvent, steam distillation or mechanical pressing. Of these extraction techniques, solvent extraction techniques are highly dependent on the diffusion of solvent to the plant cell wall . In fact, it is technically and scientifically challenging to handle. Solvent extractions require massive consumption of non-environmental friendly and toxic organic solvents that lead to waste generation. It is also complex and requires long operating hours to operate, which is energy-intensive. Furthermore, extra purification steps are needed to remove the solvent and purify the final product to ensure it is safe for consumption. More intently, the prolonged operating conditions may degrade some of the lipophilic bioactive compounds or unsaturated fatty acid in oil, negatively affecting the quality of the extracted oil. Thus, the shortcomings of existing classical separation methods have forced the industries to search for green extraction techniques that can reduce energy consumption and wastes as well as to replace organic solvents with alternative green solvents whilst improving the yield and quality of the oil.

One such green technique that is becoming popular in the industries today is ultrasound assisted extraction (UAE). Ultrasound application works on the principle of cavitation or oscillation phenomenon via either using ultrasound probe or ultrasound bath that operates at 20 kHz and 40 kHz frequencies, respectively (Fig. 1). Ultrasonic waves generate vibrations that can create voids that transfer energy to solid particles immersed in the extraction. In addition, cavitation bubbles grow closer to the solid surface and collapse at a higher amplitude forcing the cell wall to rupture, further accelerating the transfer of desired compounds trapped inside into the solvent medium .the effect generates through independent or combined mechanisms in between fragmentation, erosion, sono-capillarity, sonoporation, shear forces, and detexturation. Cavitation created by ultrasound outperformed conventional extraction approaches ).

In fats and oils application, ultrasound technology has been employed to extract oil from oilseeds and other promising crops. It was shown to be able to increase oil extraction yield as well as promote the extraction of phytochemicals. UAE offers several benefits as compared to the conventional methods. It requires a simple and easy instrumental setup. UAE is also environmentally friendly and economically feasible to be adopted. It requires less amount of solvent for the extraction, low energy throughput, and is highly efficient in extracting oil.