Extraction and Analysis of Phenolic Compounds from Grape Berries

Phenolics are ubiquitous compounds that represent the most abundant and diverse class of plant metabolites. From an analytical point of view, phenolics can be divided into soluble phenolics such as phenolic acids, phenylpropanoids, flavonoids and quinones, and nonsoluble compounds such as proanthocyanidins, lignins, and cell wall-bound hydroxycinnamic acids. Extraction of phenolics from the sample material is the first step toward their analysis. Biochemical methods for determination of total phenolics content were widely used in the past but modern chromatographic and mass spectrometric methods for identification and quantification of individual compounds are available in recent years. In this chapter, we describe methods for phenolic compounds extraction used in our laboratories from berries of Vitis vinifera and analytical methods including HPLC coupled to DAD detector and Q-TOF LC/MS for their analysis.