The most common factors affecting the extraction processes are matrix properties of the raw material, solvent temperature, pressure and duration of treatment (Hernandez, Lobo, & Gonzalez, 2009).
In order to obtain bioactive compounds from the natural plants and PCTOC raw material, the existing techniques are: (1) soxhlet extraction, (2) maceration and (3) hydro-distillation. Non-conventional techniques involve: (1) ultrasound-assisted extraction, (2) pulsed-electric field extraction, (3) enzyme-assisted extraction, (4) microwave assisted extraction, (5) pressurised liquid extraction and (6) supercritical fluid extraction and detailed procedures can be found elsewhere (Azmir et al., 2013).