HPLC METHOD FOR EVALUATION OF THE FREE RADICAL-SCAVENGING ACTIVITY OFFOODS BY USING 1,1-DIPHENYL-2-PICRYLHYDRAZYL

An HPLC method for evaluation of the free radical-scavenging activity of foods by using 1,1-diphenyl-2-picryIhydrazyl (DPPH) is reported. Th e activity was evaluated by measuring the decrease of DPPH detected at 517 nm. By using this novel method, we determined the free radical-sc avenging activity of several antioxidants: ascorbic acid, alpha-tocoph erol, Trolox, and cysteine. The results gave good correlation between the radical-scavenging activity determined by HPLC and by conventional colorimetry. This methodology was applied to determine the free radic al-scavenging activity of 8 beverages. The activity of coffee was the highest, followed by red wine, green tea, oolong tea, black tea, rose wine, white wine, and orange juice. The results well agree with those of previous reports. This method is expected to be useful for a simple and rapid determination of free radical-scavenging activity in colore d foods, because coloring substances in foods do not interfere with th e measurement.