Canola protein recovery

Defatted oil seed meals are known to contain large amounts of nutritional proteins which can be recovered for use in food and pharmaceutical industries. Protein recovery from solution is often achieved through precipitation followed by solids-liquid separation. For efficient recovery, it is imperative to maximize the solids yield and the mean particle size, and minimize the spread of particle size distribution (PSD). In this research program, recovery of canola and sunflower protein precipitates has been investigated. Three different types of precipitators (batch, MSMPR, and tubular) and four different precipitants (HCl, carboxymethylcellulose (CMC), sodium... 

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... 

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. 

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