SUPEROXIDE ANION RADICAL-SCAVENGING ABILI TY OF FRESH AND HEATED VEGETABLE JUICES

Twenty vegetable juices were investigated for the scavenging abilities of the superoxide anion radical (O-2(-)) and their change during heat processing using xanthine-xanthine oxidase system (nitro blue tetrazo lium (NBT) and luminescence methods). The fresh vegetable juices were cooked by five methods. All fresh vegetable juices had O-2(-) scavengi ng abilities measured by the NET method. Furthermore, the juices of br occoli, cabbage, green pepper and leek showed the strongest abilities of all. The abilities of the juices from carrot, tomato, onion and bea n sprout decreased due to heating process, particularly boiling and mi crowave cooking. The juices of vegetable rich in chlorophylls had also the strongest abilities, except for cucumber, Japanese pumpkin and le ttuce after heating. Considerable amounts of chlorophyll a remained in spinach after cooking, although its scavenging ability was lower than that of beta-carotene and alpha-tocopherol. Fresh carrot juice showed the strong scavenging ability by NET method, but it did not show the activity by luminescence method.