Canola protein isolation

Paulson, A.T. Tung, M.A. Solubility, hydrophobicity and net charge of succinylated canola protein isolate. J. Food Sci. 1987, 52, 1557-1561. 

So far, two processes involving membrane separation for canola protein isolation are considered promising, and both are currently under commercial development Researchers at the University of Toronto developed a membrane-based process for canola protein isolation from defatted meal [29,42], in which, after precipitation, the soluble proteins were ultraflltered to be concentrated and diaflltered for purification. Two protein isolates were produced precipitated and soluble, with a combined protein recovery of more than 70% of total meal protein. Both products were high in protein (>85%), low in phytates (<1%), essentially free of glucosinolates (<2 (xmol/g) and had desirable functional properties comparable to those of soy protein. While the methionine content of both protein isolates was similar to the reported values, the soluble product was found to have a higher level of lysine than any canola proteins obtained before, and the precipitated protein isolate was, on the other hand, farther enriched with leucine [43]. This amino acid composition makes them suitable for nse in infant formulae (Table 4.6). Despite their excellent nutritive quality. 

Essential Amino Acid Composition of Products of Membrane-Based Canola Protein Isolation (g/100 g Protein)... 

Source From Tzeng, Y. M. 1987. Process development for the production of high-quality rape-seed (canola) protein isolates using membrane technology. Ph.D. Thesis. University of Toronto, Toronto, Canada. With permission. 

FIGURE 4.8 Membrane-based process for canola protein isolation. (From Jones, J. D. and Holme, J. 1979. Oilseed processing. US Patent 4,158,656 Diosady, L. L., Xu, L. and Chen, B. K. 2005. Production of high-quality protein isolates from defatted meals of Brassica seeds. US Patent 6,905,713. With permission.)... 

FIGURE 4.9 Buicon s process of canola protein isolation. (From Barker, L. D., Martens, R. W. and Murray, E. D. 2010. Prodnction of oil seed protein isolate. US Patent 7,687,087 B2. With permission.)... 

Xu, L. and Diosady, L. L. 2002. Removal of phenolic compounds in the production of high-quality canola protein isolates. Food Res. Int. 35 23-30. 

Like soy proteins, extracted canola proteins were typically recovered by isoelectric precipitation. The precipitates, after being washed and dried, constitute the protein isolate. Due to the complex protein compositions and varietal differences among canola strains, a wide range of isoelectric points was observed, at each of which only a specific fraction of the extracted protein was precipitated, therefore protein recovery of single-step isoelectric precipitation was usually low. The highest ever reported was 65.7% of the amount of protein extracted at pH 11, obtained at pH 3.6 [32]. Moderate increase in protein yield was achieved by the same researchers with multi-isoelectric precipitation at different pH. Therefore, the further improvement in overall protein output hinges on the recovery of fractions that were not precipitated, and these proteins, due to their high solubility, are ideal for many food applications. 

Since canola proteins are large molecules with molecular weights >10,000, membrane technology was investigated as an effective means for their recovery. Ultraflltration uses semi-permeable membranes to selectively pass or retain solutes of interest, thus achieving isolation or concentration and purification. Woik in this area has been inspired by a wide variety of applications of manbrane technology in the food industry, especially the diary and soyabean sectors and the great strides in... 

Burcon NutraScience Corporation, a venture capital company founded at the turn of the century and specialized in the commercialization of canola proteins, adopted a unique process based on salt extraction [47], Saline of 0.15 M was used as the extractant. As shown in Figure 4.9, after extraction the resulting protein solution was concentrated by ultrafiltration to a concentration in excess of 200 g/L, and then diluted with chilled water at a temperature below 15°C to form a protein micellar mass (PMM), which accounted for 40-60% extracted protein, depending on the initial protein concentration and dilution ratio. PMM was settled, separated from supernatant and dried to obtain a protein isolate with a protein content over 100% (N X 6.25). The supernatant was processed to recover additional proteins by further... 

Vegetable proteins other than that from soy have potential appHcability in food products. Functional characteristics of vegetable protein products are important factors in determining their uses in food products. Concentrates or isolates of proteins from cotton (qv) seed (116), peanuts (117), rape seed (canola) (118,119), sunflower (120), safflower (121), oats (122), lupin (123), okra (124), and com germ (125,126) have been evaluated for functional characteristics, and for utility in protein components of baked products (127), meat products (128), and milk-type beverages (129) (see Dairy substitutes). 

---