From Rapeseed to a 'Canadian Oil'
The journey of canola oil begins with the rapeseed plant, a member of the mustard family (Brassicaceae) which also includes cabbage, broccoli, and cauliflower. For centuries, traditional rapeseed oil contained high levels of erucic acid, a fatty acid that was undesirable for human consumption and limited its use to industrial applications. In the 1970s, Canadian plant breeders used traditional cross-breeding methods to cultivate a new version of the rapeseed plant.
This new, genetically different cultivar produced oil that was low in erucic acid and glucosinolates. To differentiate this new, edible oil from its industrial counterpart, the name 'canola' was coined, an abbreviation of Canadian oil, low acid. The result was an entirely new product, prized for its nutritional profile and mild flavor.
The Anatomy of a Canola Seed
The canola plant produces vibrant yellow flowers that mature into pods, each containing tiny, black seeds. These seeds are remarkably oil-rich, with approximately 45% of their mass composed of oil. The rest of the seed, known as canola meal, is rich in protein and is used primarily for animal feed. The nutritional makeup of the oil itself consists of low saturated fat content (around 7%), high levels of monounsaturated fat (around 63%), and a balanced mix of polyunsaturated fats, including omega-3 and omega-6 fatty acids.
The Modern Extraction and Refining Process
To turn the raw seed into the clear, mild oil found in supermarkets, a multi-step industrial process is used:
- Cleaning: The harvested seeds are first cleaned thoroughly to remove any impurities like stems or dirt.
- Flaking: The seeds are heated and then crushed and rolled into thin flakes. This ruptures the oil cells and makes extraction more efficient.
- Pressing: The flakes are sent to expeller presses, where intense pressure mechanically squeezes out a significant portion of the oil.
- Solvent Extraction: To maximize oil yield, the remaining seed material (called 'presscake') is washed with a chemical solvent, most commonly hexane. The hexane is then removed and recycled, ensuring none remains in the final product.
- Refining: The extracted oil goes through several refining stages to improve its color, odor, and flavor, and to ensure shelf stability. This involves removing free fatty acids, gums, and other impurities.
- Deodorizing: Steam distillation is used to remove any residual aroma or taste.
Canola Oil vs. Rapeseed Oil: A Crucial Comparison
The distinction between modern canola and its ancestor, traditional rapeseed, is critical for understanding its food-safe nature. While both come from plants in the Brassica family, their chemical compositions are fundamentally different.
| Feature | Canola Oil | Traditional Rapeseed Oil |
|---|---|---|
| Source | Cultivar of Brassica plants (B. napus, B. rapa) bred for low toxicity. | Older, traditional varieties of the rapeseed plant. |
| Erucic Acid Content | Less than 2%, meeting international food safety standards. | Can be as high as 50%, considered harmful for human consumption in large quantities. |
| Glucosinolates | Low levels, less than 30 µmol/g in the leftover meal. | High levels, imparting an unpleasant taste and considered undesirable. |
| Primary Use | Edible cooking and food processing oil. | Industrial applications, such as lubricants. |
Are All Canola Plants Genetically Modified (GMO)?
While canola was originally developed through traditional plant breeding, a significant portion of the canola crop grown today, especially in North America, has been genetically modified. This was done to give the plants herbicide tolerance, helping farmers control weeds more effectively and promoting sustainable, no-tillage farming practices. However, it's important to note that the refining process removes all protein from the oil, meaning that the final oil product from a GMO plant is chemically identical to that from a non-GMO plant. For consumers who wish to avoid GMOs, non-GMO and certified organic options are available, which use cold-pressing or expeller-pressing methods.
What About Cold-Pressed Canola Oil?
Cold-pressed canola oil is produced by mechanically pressing the seeds without using high heat or chemical solvents. This method yields a more flavorful oil that retains more of the seed's original nutrients, like vitamin E. However, it is typically produced in smaller batches and has a stronger, more robust flavor profile compared to its neutral-tasting, refined counterpart. Expeller-pressed oil is another alternative that uses only mechanical pressure but may still use heat, and may be deodorized.
Conclusion: The Final Word on What Canola Oil is Made of
Canola oil is not the same as traditional rapeseed oil. It is derived from the crushed seeds of specially bred canola plants, which are processed to produce a safe and heart-healthy culinary oil. From the field to the bottle, the journey involves careful cultivation, efficient extraction, and a refining process that removes impurities while maintaining its desirable fatty acid profile. Whether it's the widely available, refined version or a specialized cold-pressed variety, what canola oil is really made of is a testament to decades of agricultural innovation, resulting in a versatile cooking staple.
