Protein is an essential macronutrient crucial for growth, tissue repair, and the maintenance of vital bodily functions. However, the rising costs of animal-based protein and the prevalence of malnutrition, particularly in developing countries, where inadequate nutrient intake remains a significant public health concern, present ongoing challenges.
To address these issues, scientists are increasingly exploring plant-based alternative protein sources, focusing on those that can be recovered from agro-industrial byproducts. In this context, canola emerges as a promising candidate – a potential affordable protein source to meet global nutritional needs. Recent research by Cháirez-Jiménez et al. (2023) studies this potential, investigating the impact of different extraction and purification methods on the production of canola protein isolates.
The canola challenge
In the edible oil industry, raw seeds are processed to extract oil. During this process nonetheless, a large amount of defatted residues is generated, which has been found to have an outstanding protein content, and potentially suitable for human consumption.
As the third most cultivated oilseed crop globally, following palm and soybean, canola stands out as an ideal candidate for bioprocessing technology. It has been found that post-oil extraction, canola meal, the main byproduct, contains between 36% and 40% protein on a dry weight basis.
Despite its potential, several obstacles prevent canola meal from becoming a widely accepted alternative protein source, with sensory characteristics being a primary concern. The meal’s color, flavor, and the presence of antinutritional compounds limit its direct use in the food industry, despite its well-balanced essential amino acid profile. For these reasons, extracting and purifying proteins from canola meal can significantly enhance its quality and functionality, broadening its application in various food products. While large quantities of defatted canola meal are produced globally, its adoption as a food ingredient remains restricted due to challenges in efficiently separating the protein from non-protein components, such as fiber, phenols, and glucosinolates. Overcoming this obstacle requires the development of a process that can effectively remove these non-protein compounds.
Innovative extraction and purification techniques
Cháirez-Jiménez et al. (2023) explored various methods for extracting and purifying proteins from canola meal to enhance its potential as a food ingredient, focusing on improving the sensory attributes and removing non-protein components. The study investigated different extraction techniques, including alkaline extraction, followed by purification approaches like precipitation and ultrafiltration. Among these, alkaline extraction combined with ultrafiltration, was found to enhance yield and protein recovery. This persisted when adding the ethanol pretreatment to the same alkaline extraction and ultrafiltration technique where the highest crude protein (89.71 %) was obtained, as well as free amino nitrogen contents. In general, both this methods suggest that they can be used to obtain canola protein isolates with high added value for use in food formulations.
However, challenges persist in removing glucosinolates, which contribute to bitter flavors. Ultrafiltration showed potential in reducing these compounds, though further optimization is needed to balance protein recovery with sensory quality.
The purified canola protein isolates demonstrated enhanced solubility, foaming, and emulsifying properties, making them suitable for various food applications. This study underscores the need for refining these processes to overcome the sensory and functional limitations of canola protein isolates, ultimately making canola meal a more viable and attractive option for sustainable, cost-effective food production.
The role of canola in the food industry
While all methods tested successfully produced canola protein isolates, certain approaches – such as ethanol pretreatment, alkaline extraction, and ultrafiltration – demonstrated significantly higher process yields, protein recovery, and superior amino acid profiles. Due to these promising results, researchers believe these methods could be scaled up to a pilot plant model, showing strong potential for broader application in food production.
The study’s significance lies in the potential to revalorize canola meal, the primary by-product of oil extraction, as a valuable alternative protein source for various applications in the food industry.
