ABSTRACT
When identifying a natural product or a derived extract as a potential source of polyphenols, it is necessary to carry out a comprehensive analysis of their polyphenol content and prole. However, this may become a difcult task for a nonexpert in the topic because of the wide diversity that polyphenols exhibit in different relevant aspects. Polyphenols differ in polarity (from the very hydrophilic simplest phenolic acids to the lipophilic alkylresorcinols), molecular weight (MW) (from small phenolic acids to polymeric hydrolyzable tannins), and molecular structure, such as isomers (e.g., cis-resveratrol and trans-resveratrol). In addition, they present different forms of associations with food matrices (they may appear free, associated with weaker bonds or strongly linked with covalent bonds). Therefore, this chapter is a practical guide for those who are not familiar with the eld. We will cover topics
6.1 Introduction .................................................................................................. 193 6.2 Spectrophotometry Techniques .................................................................... 194
6.2.1 The Folin-Ciocalteau Assay............................................................. 194 6.2.2 pH Differential Method for Anthocyanidins .................................... 194
6.3 Chromatography Techniques ........................................................................ 196 6.4 Mass Spectrometry Techniques .................................................................... 199
6.4.1 Ionization Sources of MS ................................................................. 199 6.4.2 Mass Analyzers.................................................................................200 6.4.3 Approaches for the Identication of Polyphenols .............................203
