Extraction, nutrition, functionality and commercial applications of canola proteins as an underutilized plant protein source for human nutrition

Concerns about sustainability and nutrition security have encouraged the food sector to replace animal proteins in food formulations with underutilized plant protein sources and their co-products. In this scenario, canola protein-rich materials produced after oil extraction, including canola cold-pressed cakes and meals, offer an excellent opportunity, considering their nutritional advantages such as a well-balanced amino acid composition and their potential bioactivity. However, radical differences among major proteins (i.e., cruciferin and napin) in terms of the physicochemical properties, and the presence of a wide array of antinutritional factors in canola, impede the production of a highly pure protein extract with a reasonable extraction yield. In this manuscript, principles regarding the extraction methods applicable for the production of canola protein concentrates and isolates are explored in detail. Alkaline and salt extraction methods are presented as the primary isolation methods, which result in cruciferin-rich and napin-rich isolates with different nutritional and functional properties. Since a harsh alkaline condition would result in an inferior functionality in protein isolates, strategies are recommended to reduce the required solvent alkalinity, including using a combination of salt and alkaline and employing membrane technologies, application of proteases and carbohydrases to facilitate the protein solubilization from biomass, and novel green physical methods, such as ultrasound and microwave treatments. In terms of the commercialization progress, several canola protein products have received a GRAS notification so far, which facilitates their incorporation in food formulations, such as bakery, beverages, salad dressings, meat products and meat analogues, and dairies.