VARIATIONS IN ANTIOXIDANT ACTIVITY IN BROCCOLI (BRASSICA OLERACEA L.) CULTIVARS

Abstract

ABSTRACT 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, β-carotene, α-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 β-carotene content. Total antioxidant activity as determined by ferric reducing antioxidant power ranged from 2.05 to 3.56 µmol 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. PRACTICAL APPLICATIONS Broccoli is a potential healthy vegetable with enhanced antioxidant activity because of its high phenolic content. It also comprises a mixture of other antioxidants including ascorbic acid, carotenoids and α-tocopherol which are known to prevent the onset of chronic diseases. Among broccoli cultivars, Aishwarya, Packman and Punjab broccoli seem to be promising ones, to be used in breeding programs to improve the quality of broccoli under Indian conditions.