Polyphenols analysis and related challenges

The aim of this chapter is to give the reader a broad view on the developed methods for polyphenol extraction and analysis. The different workflows and steps involved in the analysis of polyphenols from plants and food (by-products) are presented. Conventional extraction techniques employed for the extraction of polyphenols from natural samples are described besides the use of advanced extraction techniques such as supercritical fluid, carbon dioxide–expanded liquid, pressurized liquid, pressurized hot water, ultrasound-assisted extraction, and microwave-assisted extraction, among others. Furthermore, the spectrophotometric methods used to determine polyphenols as well as to measure the antioxidant capacity of their extracts are critically discussed. Finally, the state-of-the-art on the advanced analytical techniques applied to the characterization of polyphenols is also addressed and discussed.