An integrated method of isolating napin and cruciferin from defatted canola meal

Canola proteins are known to have great potential for use in food and non-food applications due to their nutritional, biological and functional properties. However, canola protein extraction remains a challenge, due mainly to the complexity of canola proteins and the presence a variety of undesirable compounds. An integrated method, including acidic washing (pH 4), alkaline extraction (pH 12.5), isoelectric precipitation (pH 4), and ultrafiltration, was proposed to isolate two main canola proteins: cruciferin and napin. The protein content and yield of cruciferin and napin were 91 g/100 g and 38.6%, 82 g/100 g and 12.5%, respectively. The contents of phytic acid and phenolics were 1.5 g/100 g and 1.8 g/100 g, and 0.9 g/100 g and 0.6 g/100 g, respectively, for cruciferin and napin. The emulsifying and foaming properties of cruciferin and napin were favorably comparable to previous results. The development of a simple and scalable method of canola protein isolation will facilitate further research on their food and non-food applications.