free radical scavenging capability of various defatted sesame seed cakes and hulls using epr compared with in vitro testing and hplc analysis the free radical scavenging activities of black and white sesame seed hulls and the powder of black and white sesame seed cakes were investigated using noninvasive continuous wave electron paramagnetic resonance epr and antioxidant assays with black sesame seed hulls and the powder of black sesame seed cakes epr detected the very strong singleline signal intensities that correspond to the stable organic radicals while the spectrum of the white sesame seed hulls and the white sesame seed cakes showed no signal the in vitro antioxidant activities of black and white sesame seed cake extract were evaluated by dpph free radical scavenging activity hydrogen peroxide scavenging activity and ferric reducing antioxidant power frap assay the results indicated that the extract from black sesame seed cake possessed a greater dpph radical inhibitory activity and hydrogen peroxide inhibitory activity than white sesame seed cake extract with ic50 values of 0847 0011 mgml and 0338 0007 mgml respectively black sesame seed cake extract also showed a strong reducing power with a frap value of 1307 0037 mm fe iig of extract weight and an ec1 value of 0683 0002 mgml the main compounds from the black and white sesame seed cake extracts were analysed using highperformance liquid chromatography hplc the results revealed that the main compounds in black and white sesame seed cake extracts were in a group of watersoluble lignans mainly sesaminol triglucoside and sesaminol diglucoside however sesaminol diglucoside was found in large amounts in the black sesame seed cake extract while it was found in a very small amount in the white sesame seed cake extract therefore these results demonstrated considerable antioxidant capacity of the sesame seed especially in the black strain