Mass spectrometry in grape and wine chemistry. Part I: Polyphenols

Abstract

I. Introduction 218 II. Quality Improvement 219 III. Grape and Wine Polyphenols 220 IV. Mass Spectrometry in the Study of Polyphenols and Procyanidins 222 V. Mass Spectrometry in the Study of Anthocyanins and their Derivatives 229 VI. Mass Spectrometry in the Study of Structures Formed by Polymerization of Anthocyanins and Flavan‐3‐ols 234 VII. Mass Spectrometry and Grape and Wine Resveratrol 240 VIII. Application of MALDI in the Study of Polyphenols 243 IX. Mass Spectrometry Applied to the Study of Wine Polyphenols from Cork Bottle Stoppers and Oak Barrels 245 X. Conclusions 246 References 247 Mass spectrometry, had and still has, a very important role for research and quality control in the viticulture and enology field, and its analytical power is relevant for structural studies on aroma and polyphenolic compounds. Polyphenols are responsible for the taste and color of wine, and confer astringency and structure to the beverage. The knowledge of the anthocyanic structure is very important to predict the aging attitude of wine, and to attempt to resolve problems about color stability. Moreover, polyphenols are the main compounds related to the benefits of wine consumption in the diet, because of their properties in the treatment of circulatory disorders such as capillary fragility, peripheral chronic venous insufficiency, and microangiopathy of the retina. Liquid Chromatography‐Mass Spectrometry (LC‐MS) techniques are nowadays the best analytical approach to study polyphenols in grape extracts and wine, and are the most effective tool in the study of the structure of anthocyanins. The MS/MS approach is a very powerful tool that permits anthocyanin aglycone and sugar moiety characterization. LC‐MS allows the characterization of complex structures of grape polyphenols, such as procyanidins, proanthocyanidins, prodelphinidins, and tannins, and provides experimental evidence for structures that were previously only hypothesized. The matrix‐assisted‐laser‐desorption‐ionization‐time‐of‐flight (MALDI‐TOF) technique is suitable to determine the presence of molecules of higher molecular weight with high accuracy, and it has been applied with success to study procyanidin oligomers up to heptamers in the reflectron mode, and up to nonamers in the linear mode. The levels of resveratrol in wine, an important polyphenol well‐known for its beneficial effects, have been determined by SPME and LC‐MS, and the former approach led to the best results in terms of sensitivity. © 2003 Wiley Periodicals, Inc., Mass Spec Rev 22:218–250, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com). DOI 10.1002/mas.10052