Abstract:Grape-seed crude protein which was purple brown in color was extracted from the Ningxia local grape seed used as raw material，by an alkali-solution and acid-isolation method.Herein，the decolorization of crude protein was studied.A bleaching method with H2O2as a kind of decolorant was finally selected through comparing the bleaching effects with active carbon and H2O2.The results showed that in bleaching，the conditions for whiteness and yield were restricting each other.Therefore，the bleaching conditions must be selected by comprehensively considering the actual demands.The optimum bleaching conditions were found by the singlefactor and orthogonal experiments and with the two aspects of whiteness and yield in consideration.The optimum conditions were that the solid-liquid ratio was 1∶25（g/mL），pH was 8.0，the quantity of H2O2was 15 mL，the bleaching time was 40 min，and the bleaching temperature was 55℃.The decolorized grape seed protein with a whiteness of 14.71 was produced under the optimum conditions，and the yield of the decolorized grape seed protein was 78.21%.