**3.2. Advanced methods of extraction**

Classical extraction methods are dominated in many laboratory facilities mainly due to its simplicity and low economic cost. Nonetheless, many scientific reports have shown that maceration, percolation and Soxhlet extraction have low efficiency and several environmental issues due to the pollution caused in the environment when large volumes of organic solvents are used. Moreover, the classical extraction often requires a recovery step followed by evaporation to concentrate the extract, which makes it a high time-consuming process. To overcome these constraints, a number of methods have been developed in the last years such as microwave-assisted extraction (MAE); ultrasound-assisted extraction (UAE); supercritical CO2 extraction (SC-CO<sup>2</sup> ); pressurized fluid extraction (PFE); enzymeassisted extraction (EAE) or even combined approaches. From the hundreds of papers published until now, it seems that these novel extraction techniques can be an interesting choice for classical extraction methods, offering several advantages such as less extraction time length, less volume of solvents, less final toxic residues, higher extraction yields and better reproducibility.

Hundreds of works have been published (some of them listed in **Table 3**) [63–73] about the use of such methods to improve the extraction yield of polyphenols in different matrices. In the next paragraphs is presented a detailed description of each method.
