367 Scavenging Capacity of Active Oxygen Species in Blackberry

The effect of blackberries ( Rubus sp.) genotypes on antioxidant activities against superoxide radicals (O 2 – ), hydrogen peroxide (H 2 O 2 ), hydroxyl radicals (OH), and singlet oxygen (O,), was evaluated. The results were expressed as percent inhibition of active oxygen species production in the presence of fruit juice. The active oxygen radical absorbance capacity (ORAC) value referred to the net protection in the presence of fruit juice, and was expressed as micromoles of α-tocopherol, ascorbate, α-tocopherol, and β-carotene equivalents per 10 g of fresh weight for O 2 – , H 2 O 2 , OH, and O 2 , respectively. Among the different cultivars, juice of Hull' blackberry had the highest oxygen species, superoxide radicals (O 2 – ), hydrogen peroxide (H 2 O 2 ), hydroxyl radicals (OH), and singlet oxygen (O 2 ,) scavenging capacity. Different antioxidants have their functional scavenging capacity against active oxygen species. There were interesting and marked differences among the different antioxidants in their abilities to inhibit the different active oxygen species. β-carotene had by far the highest scavenging activity against O 2 – but had absolutely no effect on H 2 O2. Ascorbic acid was the best at inhibiting H 2 O 2 free radical activity. For OH, there was a wide range of scavenging capacities with α-tocopherol the highest and ascorbic acid the lowest. Glutathione had higher O 2 – scavenging capacity compared to the other antioxidants.