Abstract: The technology and condition about sequentially hydrolyzing rapeseed isolated protein by 2709 alkaline proteinase and pawpaw proteinase were studied.Methods that were oxygenizing pigment by H2O2 and modifiying peptide by acetic anhydride in the hydrolyzate were developed.It showed that extraction rate of rapeseed isolated protein was 73.6%while NaOH concentration was 1%,the temperature 60℃and extracting time 5 hours where as in the brown powder.protein content was 91.5%,glucoraphenin 0.024%,and phytic acid 0.32%.The isolated protein was sequentially hydrolyzed by 2709 alkaline proteinase at E/S (U/g)=5×103,50±1℃,pH10.0,60mins and Pawpaw proteinase at E/S(U/g)=5×103 ,55±1℃,pH7.5,60mins.The hydroly sis degree(DH%) was arrived at 17.15%.During the reaction,DH%of 2709 alkaline proteinase was 59.3%,but pawpaw proteinase 40.7%and the isoelectric point remained at pH3.5.The light yellow protein with yield 94.83%was obtained through oxygenizing pigment while the temperature was above 80℃and ratio of H2O2/protein (V/W) from 1.25 to 1.5.Through acid lating reaction alith rate of acetic anhydride to the proteins 30%,the separated protein isoelectric point was pH4.0 and protein concentration in water liquid 18.47mg/ml,but no peculiar smell was found at 20℃and pH9.0～9.5.

Key words: Rapeseed separated protein , Proteinase H2O2 , Acetic anhydride