In this study, the process of sinapine removal from surface-active substances extracted from defatted rapeseed cake was established by using a mixed organic solvent system (diethylether:ethyl acetate = 1:1, v/v). The emulsifying properties of the purified surface-active substances were investigated. Thin layer chromatogram showed that sinapine was removed and purified surface-active substances were found to have better emulsifying properties compared to a non-purified one or commercial soy lecithin. As for interfacial tension data, purified surface-active substances showed values lower (10-1 wt%: 3.20±0.57 mN/m) than the non-purified ones (10-1 wt%: 14.16±0.27 mN/m). In addition, we found that fat globule size in emulsions with purified surface-active substances was much smaller than in emulsions with non-purified substances or commercial soy lecithin. These results could be attributable to the increased amount of phospholipids in purified substances following sinapine-removal.