Phenolic compounds and antioxidant activity of Macedonian red wines

The quantitative composition of phenolic compounds and antioxidant activity of Vranec, Merlot and Cabernet Sauvignon wines produced in 2006, 2007 and 2008 were determined and compared. The phenolic profile was established using high-performance liquid chromatography coupled with diode array detector and on line mass spectrometry (HPLC-DAD–ESI-MS and MS/MS) technique. A total of 65 phenolic compounds were determined in the wines including 14 anthocyanins, 18 pyranoanthocyanins, 16 flavonols, 8 hydroxycinnamic acids and their derivatives, 4 stilbenes, gallic acid and 4 flavan-3-ols. Hydroxyphenyl-pyranoanthocyanin content is reported for the first time in Macedonian red wines, ranging between 1.09 and 10.4 mg/L. 10-Carboxy-pyranomalvidin-3-glucoside and 10-p-hydroxyphenyl-pyranomalvidin-3-glucoside were the main compounds from vitisin-like and hydroxyphenyl-like pyranoanthocyanins, respectively. Vranec wines produced in 2008 presented highest concentration of anthocyanins (508 mg/L), vitisins (53.1 mg/L), hydroxyphenyl-pyranoanthocyanins (7.35 mg/L), flavonols (120 mg/L), hydroxycinnamic acid derivatives (352 mg/L), flavan-3-ols (98.9 mg/L), stilbenes (43.9 mg/L) and antioxidant activity (12.5 mM/L TE). Cabernet Sauvignon and Merlot had highest flavonols (152 and 119 mg/L) and flavan-3-ols concentration (150 and 111 mg/L) in 2006 and 2007, respectively, indicating the important role of variety, climate, storage conditions and winemaking techniques in wine phenolic composition. Factor analysis showed classification of wines according to the variety and content of the phenolic families and color characteristics