Variations in antioxidant activity in broccoli (Brassica oleracea L.) cultivars

Bioactive compounds were investigated in eight cultivars of broccoli grown under North Indian conditions over 2 years. The cultivars showed significant differences in phenols, antioxidant activity and other antioxidant constituents including ascorbic acid, beta-carotene, alpha-tocopherol and chlorophyll. Free phenolics ranged from 19.60 to 41.40 mg/100 g fresh weight and on an average constituted 73% of total extractable phenolics. Cultivars Punjab broccoli and Packman had the highest ascorbic acid content, whereas green sprouting broccoli had the highest beta-carotene content. Total antioxidant activity as determined by ferric reducing antioxidant power ranged from 2.05 to 3.56 mu mol Trolox/g fresh weight. Free radical scavenging activity as estimated by 2, 2-diphenyl-1-picrylhydrazyl, ranged from 57 to 74%. There was strong positive correlation between free phenolics and antioxidant activity. Results indicate that both cultivars and year affect the bioactive composition in broccoli.