Defatted white and gold sesame seed flour, recovered as a byproduct after sesame oil extraction, was
extracted with 70% ethanol to obtain polar-soluble crude extracts. The in vitro antioxidant activity of
the extract was evaluated by DPPH free radical scavenging activity and oxygen radical absorbing capacity
(ORAC). The polar-soluble crude extracts of both sesame seed types exhibited good antioxidant capacity,
especially by the ORAC method with 34,720 and 21,700 lmol Trolox equivalent/100 g of white and gold
sesame seed extract, respectively. HPLC, butanol extraction, and UPLC–MS analyses showed that different
compounds contributed to the antioxidant activity of the polar-soluble crude extracts. Sesaminol glycosides
were identified in the butanol-soluble fractions; whereas, purified water-soluble fraction contained
ferulic and vanillic acids. This study shows that hydrophilic antioxidants in the purified water-soluble
fraction contributed to the antioxidant activity of white and gold sesame seed polar-soluble crude
extracts.