Classification of Wines Based on Different Antioxidant Responses to Spectrophotometric Analytical Methods

Abstract

Six well established spectrophotometric assays (Folin-Ciocalteu, DPPH, ABTS^•+, FRAP, CUPRAC, and the o-diphenols method) have been complementary implemented in order to estimate the total phenolic and o-diphenolic content as well as the free radical scavenging and reducing antioxidant capacities of 40 white and 10 red wines of different varieties and geographic origin. In white wines, the results were weakly correlated; whereas, the results in red wines were strongly correlated, therefore, postulating their separate use in order to estimate efficiently the correlation between results of these methods. The results were subjected to the unsupervised PCA pattern recognition method to investigate the possible classification of white wines. PC analysis framed the wine samples in clear clusters, when the extracted PCA model was based on the results of all six spectrophotometric assays. The usefulness of implementing assays based on different antioxidant mechanisms is discussed. To our knowledge, this is the first time different responses of antioxidants to these spectrophotometric assays have been used to classify white wines according to their variety.

Keywords:

• ABTS^•+
• CUPRAC
• DPPH
• FRAP
• Polyphenols
• Wine classification

Acknowledgments

This paper is part of a special issue organized by Dr. Nikolaos Thomaidis and Dr. Antony C. Calokerinos from research presented at the Aegean Analytical Chemistry Days Conference in Lesvos, Greece on 29 September–3 October 2010.

D. Christodouleas gratefully acknowledges financial support from “Alexander S. Onassis” Foundation. We would like to thank the winery Diamantakis and Domaine Karavitakis for their kind donation of premium quality wines for our study with.