Protein was recovered from five varieties and a mixed blend of cold-pressed rapeseed press cake by leaching and precipitation in a water-based process, and the protein recovery yield varied from 26-41% depending on variety. Exposure for heat during protein recovery severely reduced the rapeseed proteins' ability to stabilize the oil-water interface of emulsion droplets. Protein extract from Lyside had the best emulsifying properties of the varieties investigated. Oxidation rate was assessed by the Thiobarbituric Acid Reactive Substances (TBARS) method and rapeseed protein extracts from Epure and Festivo had higher capacity to delay oxidation compared with soy lecithin. There are possibilities to broaden the use of rapeseed whereby recovered rapeseed protein can be used as a plant-based multifunctional ingredient with emulsifying capacity and which has a delaying effect on oxidation.
Keywords: by-product; emulsifying properties; oxidative effect; protein recovery yield; rapeseed protein.