Free Radical Scavenging Capacity in the Aging of Selected Red Spanish Wines

Free radical scavenging capacity by the DPPH• method and main physicochemical properties, polyphenols content by HPLC, color by a tristimulus colorimeter, and UV−vis spectra in the aging of selected red Spanish wines, were studied. As the wines age, they become darker (lower lightness, L*) and increase their hue angle (lower red color) as well as the ratio of absorbance at 420 nm to that at 520 nm. Main polyphenolics identified in the samples were tannic acid, oenin, and gallic acid. The antiradical efficiency of the samples increased during aging, which could be related to an increase in the tannic acid concentration shown by the following correlationship: EC50 = 1/(0.18 + 0.0011[tannic acid]mg/L) with a correlation coefficient of 0.744. Keywords: Red wine; aging; free radical scavenging; polyphenols; color