Studies On Extraction, Purification And Functional Properties Of Rapeseed Protein

The single factor experiments of affecting rapeseed protein extraction ratio from hulled and squeezed double-low rapeseed assisted by ultrasonic were discussed.On that basis, the two-order polynomial equation for extraction of rapeseed protein was established and pH value, NaCl concentration, solid-liquid ratio were optimized by response surface methodology based on the central composite design. Ultrafiltration was applied to concentrate and purify the rapeseed protein extracting solution which was prepared on the optimal extraction process and effect of operating pressure,temperature,pH value and flow velocity on membrane flux was discussed.Using membrane flux as evaluation index, operating pressure,temperature and pH value were optimized by orthogonal experiment. The nitrogen soluble index,water binding capacity,oil absorbency,foamability,foam stability,emulsibility and emulsion stability of rapeseed protein isolate were mainly studies.The main results were described as follows:1,The optimal rapeseed protein extraction process parameters were determined by response surface methodology:pH value 10.4, NaCl concentration 3.2%, solid-liquid ratio 1:9.5,2 hours,3 times,at 50℃.Under those conditions,rapeseed protein extraction ratio was 60.0%,which was better than aqueous phase extraction.2,The optimal rapeseed protein extraction solution ultrafiltration process parameters were determined by orthogonal experiment:operating pressure 0.1MPa,temperature 40℃,pH value 9 and flow velocity 2m/s. Rapeseed protein isolate obtained after low temperature drying was pale yellow,contained little toxin and the purity of protein exceeded 90%. Rapeseed protein yield was 53.4%.3,The functional properties of rapeseed protein isolate gained by ultrasonic-assisted extraction and ultrafiltration technology was good and rapeseed protein isolate had great potential of meeting the needs of food industry.