Table 1.

A summary of extraction techniques used for bioactive components (isoflavones and other polyphenols).

Methods	Descriptions	Solvents	Advantages
Maceration extraction	Soybeans are left together with the solvent from hours up to days for maceration, and after that, filtration procedures clean off the extract from solid suspensions.	methanol acetone ethanol water	1. very simple; 2.very suitable technique for thermally labile components
Soxhlet extraction	It uses solvent heating to the boiling point and the returning of the condensed vapors to the flask. This way, it can be run for as many cycles as desired.	ethanol water	1. simple; 2. low cost
Ultrasound-assisted extraction (UAE)	It utilizes ultrasound to develop bubbles inside the solvent. These bubbles created by cavitation phenomenon induce wall cells’ disruption of the targets and speed up the penetration of the solvent into the target material.	ethanol water	1. shorter extraction time; 2. a reduced amount of necessary solvent; 3. lower energy consumption
Microwave-assisted extraction (MAE)	It uses microwaves, which can be absorbed by polar molecules (such as water), and facilitates diffusion of the solvent into vegetal samples and release of the solutes from the target material into the solvent.	Methanol ethanol water	1. considerable savings in time, solvent amount, energy consumption; 2. an increase in extraction efficiency
Supercritical fluid extraction (SFE)	The extraction is facilitated by means of reaching a supercritical state which occurs when the temperature and pressure of the fluid are raised above its critical point.	carbon dioxide co-solvent	fast, selective and solvent saving
Accelerated solvent extraction (ASE)	To accelerate extraction, it involves solvents under high temperature and pressure but without reaching the critical point.	methanol ethanol acetone	more suitable for the extraction of phenolics compounds than UAE