Antioxidant capacity, total phenolics, glucosinolates and colour parameters of rapeseed cultivars

The antioxidant capacity of twenty nine rapeseed varieties was determined by using ferric reducing antioxidant power (FRAP) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) methods. Mean FRAP (31906326 mu mol Trolox/100 g) and DPPH (3194-6346 mu mol Trolox/100 g) values for methanolic extracts of rapeseed cultivars did not differ significantly. Moreover, the total content of phenolics (756-1324 mg sinapic acid/100 g), glucosinolates (4.2-87.5 mu mol/g, respectively), erucic acid (0.0-56.1%) and colour parameters of the studied rapeseed cultivars were analysed. Antioxidant capacity determined by FRAP and DPPH methods correlated significantly with total phenolic content (TPC) in rapeseed cultivars (r = 0.9332, 0.9339, p < 0.001). Also, significant, inverse correlations were found between antioxidant capacity, total phenolics and luminosity (L*) or red colour intensity (a*) of rapeseed cultivars. Principal component analysis (PCA) allowed the rapeseed varieties to be differentiated based on their antioxidant capacities, total amounts of phenolics, glucosinolates, erucic acid and colour parameters. (C) 2011 Elsevier Ltd. All rights reserved.