Table 2.

Principal innovative extraction technologies applied to olive leaves: principle and operating parameters.

Extraction Technique	Principle/Mechanism	Operating Parameters	Ref
Ultrasound Assisted Extraction (UAE)	Acoustic cavitation, acoustic pressure in addition to hydrostatic pressure, micro-jetting and micro-streaming effects, cell wall breakdown and particle dislodgment	US power and frequency, amplitude, temperature, time, solvent, liquid-solid ratio	[62,73,101,102]
Microwave Assisted Extraction (MAE)	Ionic conduction and dipole rotation, conversion of electromagnetic energy to thermal energy, cell wall disruption by high pressure	MW power, time, temperature, solvent, liquid-solid ratio	[86,103,104]
Supercritical Fluid Extraction (SFE)	Increased density and reduced viscosity of extraction fluid at temperature and pressure above critical point, increased penetration and mass transfer	Supercritical fluid (CO2, the most commonly used), co-solvent, temperature, pressure, fluid flow rate	[105,106,107]
Pressurized Liquid Extraction (PLE)	Increased solubility and diffusion rate at elevated temperature (above boiling point) under pressurized condition, reduction of solvent viscosity, increased mass transfer	Number and duration of extraction cycles, solvent, pressure, temperature liquid-solid ratio	[23,53,108]
Pulsed Electric Field (PEF) extraction	Electro-permeabilization by electromechanical force, electroporation of cell membrane, increased mass transfer	Electric field intensity/input energy, pulse duration (μs) and number, extraction chamber geometry	[64,65]

US: ultrasound. MW: microwave.