Analysis of Main and Healthy Phenolic Compounds in Foods

Phenols or Phenolics is a designation corresponding to compounds that have one or more hydroxyl groups attached to a 6-carbon aromatic ring. Phenols in foods occur mainly as secondary metabolites of vegetables, often found in polymeric forms (polyphenols). Phenols from foods are mainly simple phenols (e.g., caffeic acid), flavonoids, the most varied and ubiquitous class (e.g., catechin, quercetin), stilbenes (resveratrol), lignans, and tannins. In addition to the wide range of polyphenols present in foods, the compounds are quantitatively and qualitatively distributed in a heterogenous way in the different compartments of the food matrix. This structural and compartmental diversity leads to an important variability of the physicochemical properties impacting otherwise the extraction of phenols. Total phenols are determined by the Folin Cioucalteau method, as described in European Pharmacopeaea.