Table 1.

Comparison of different extraction techniques of phenolic compounds. Advantages and drawbacks.

Extraction	Advantages	Disadvantages	Main Applications	References
LLE	Easy to use, efficient and wide-ranging applicability	Poor selectivity, low yields, formation of emulsions and high quantities of organic solvents	To process temperature-sensitive compounds and azeotropic mixtures	[15,16]
SPE	Fast, reproducible, and emulsion-free procedure. Small extract volumes can be used	Time-consuming and high solvent usage	Clean-up method of crude plant extracts	[17]
UAE	Efficient, rapid, selective, and energy-saving technique. Capable of being up-scaled in volume at industrial level	Ultrasound may cause lipid oxidation and formation of free radicals	Useful for thermolabile compounds as it does not require high temperatures	[18,19]
SFE	Rapid and selective, products free of residual solvents	Investment, high pressures, energy costs	Thermolabile compound extraction	[20]
PLE	Faster than conventional extraction techniques, low-solvent consumption	Low selectivity, high temperatures and costly equipment	Extraction of antioxidant phenolic compounds	[21]
MAE	Simple and rapid technique, low-solvent, and energy consumption	Proper selection of power to avoid high temperatures	Suitable for thermolabile phenolic compounds	[22]

Abbreviations: LLE, liquid–liquid extraction; SPE, solid-phase extraction; UAE, ultrasound-assisted extraction; SFE, supercritical fluid extraction; PLE, pressurised liquid extraction and MAE, microwave-assisted extraction.