Heat-induced pressed gels from canola press cakes: Exploring the impact of starting materials, stirring conditions, and carbohydrase pretreatment.

Alternative plant protein sources offer excellent solutions for tackling the current challenge of food insecurity and sustainability. Inspired by soy tofu, pressed gels represent a robust and versatile way to create protein-enriched plant products. Here, production of heat-induced pressed gels from canola cold-pressed cakes (CPC) and hot-pressed cakes (HPC) was investigated under varied stirring conditions. Pressed gels prepared from CPC resulted in a greater yield and protein recovery than that of HPC. While using carbohydrases as a pretreatment was ineffective in improving yield and protein recovery, applying a stirring condition during heating increased the protein recovery up to 38.3%. Also, stirring condition was proved to be able to modulate the textural properties by controlling the compactness and the size of aggregates. It is revealed that pressed gels are stabilized through a combination of hydrogen bonds, hydrophobic interactions, and disulfide bonds. In comparison to canola press cake, the pressed gels contained less glucosinolates and phenolic compounds, but more phytic acid. A mechanism of formation has been hypothesized based on the nucleation-growth mechanism, and a shift was proposed from diffusion-limited processes in non-stirred pressed gels to reaction-limited process in stirred pressed gels. In conclusion, the potential of canola heat-induced pressed gels was demonstrated both as a stand-alone product and a micro-structured protein extract.

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.