Abstract:Rapeseed meal and flaxseed meal were used as raw materials to extract rapeseed meal protein and flaxseed meal protein using the alkali-solution and acid-precipitation method. The extraction processes of both proteins were optimized through single-factor and response surface experiments，and their physicochemical and functional properties were compared and analyzed. The results of process optimization showed that the optimal conditions for rapeseed meal protein extraction were a pH of 11，an extraction time of 100 min，an extraction temperature of 55 ℃，and a solid-to-liquid ratio of 1∶25 （g/mL），under which the extraction rate was 14.27%. The optimal conditions for flaxseed meal protein extraction were a pH of 9，a first extraction time of 140 min，a second extraction time of 60 min，an extraction temperature of 60 ℃，and a solid-to-liquid ratio of 1∶20 （g/mL），under which the extraction rate was 12.96%. Quality comparison showed that，in terms of physicochemical properties，the protein contents of rapeseed meal protein and flaxseed meal protein were 72.91%and 65.57%，respectively，and their moisture contents were low，at 8.39% and 6.41%，respectively，which was favorable for storage. Regarding functional properties，rapeseed meal protein exhibited higher water-holding capacity and oil-holding capacity，at 30.81% and 17.77%，respectively，demonstrating stronger abilities to retain water and oil. Both rapeseed meal protein and flaxseed meal protein showed high emulsifying activity and emulsifying stability，at 78.32%，76.73%，84.19%，and 81.98%，respectively，indicating good emulsifying properties. The solubility of flaxseed meal protein was 69.04%，higher than that of rapeseed meal protein at 60.30%.