Free radical scavenging capacity of selected red and white wine

The free radical scavenging capacity of selected red, rosé and white Spanish wines from different grape varieties was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH·) method using a new methodology developed at our laboratory. The amount of sample necessary to decrease by 50% the initial DPPH· concentration (EC50), the time needed to reach the steady state at EC50 concentration (TEC50) and the antiradical efficiency (AE = 1/EC50TEC50) were determined in the wine samples. Some differences between rosé wines made with Garnacha and Tempranillo grape varieties were observed in the UV-vis spectra and in the free radical scavenging parameters, those from Garnacha variety having the highest antioxidant activity. The antiradical efficiency of the wines followed a decreasing order: red wines (22.44 × 10−6) > rosé wines (4.90 × 10−6) > white wines (1.88 × 10−6). There was a correlation between antiradical efficiency and total polyphenol (TP): AE = −3.33135 + 0.0180535TP; the correlation coefficient was r = 0.951454.