Review

Canola (Brassica napus)

Description

Canola is the common term used for oil obtained from specially bred low-erucic-acid, low-glucosinolate rapeseed varieties of Brassica napus (and sometimes Brassica rapa), developed mainly in Canada from the 1970s onwards to provide an oil with a more favourable and safer nutritional profile than traditional rapeseed oil. It is a clear, pale yellow to golden liquid oil with a mild flavour and light aroma, used both cold (as a dressing) and in cooking and frying thanks to its good fatty-acid profile and reasonable oxidative stability. Nutritionally it is characterised by a very low content of saturated fatty acids and a high proportion of monounsaturated and polyunsaturated fatty acids, with a useful balance between omega-6 (linoleic acid) and omega-3 (alpha-linolenic acid). Beyond edible oil, canola yields meals and cakes for animal feeding and specific fractions (such as lecithins and unsaponifiable matter) used in foods, supplements and cosmetics.

Botanical classification

• Common name: canola

• Botanical name: Brassica napus var. napus

• Family: Brassicaceae

• Origin: probably the Mediterranean and Northern Europe, with modern low-erucic, low-glucosinolate cultivars developed mainly in Canada

• General features: annual or biennial oilseed crop with rapid growth, raceme-type yellow flowers, and small seeds rich in oil and proteins; selected specifically for low erucic acid and low glucosinolate content

Cultivation and growing conditions

Climate

• Prefers cool temperate climates.

• Sensitive to prolonged thermal stress (both heat and severe cold).

• Performs best with cool springs and moderately warm summers.

• Can be grown as a winter crop in mild regions.

Exposure

• Requires full sun throughout the growing cycle.

• Insufficient light reduces flowering, seed set, and overall yield.

Soil

• Prefers deep, fertile, well-drained soils.

• Optimal pH: slightly acidic to neutral (6.0–7.0).

• Waterlogging should be avoided, as it promotes root diseases and fungal pathogens.

• Good soil structure is important for proper root development and nutrient uptake.

Irrigation

• Generally not extremely water-demanding, but adequate moisture is crucial during:

  • germination and seedling establishment,

  • stem elongation,

  • flowering and pod set.

• Excessive irrigation should be avoided: overly wet soils reduce seed quality and increase disease risk.

Temperature

• Germination: from about 5–10 °C.

• Optimal vegetative growth: around 15–22 °C.

• Winter types show good cold tolerance and can withstand short frosts.

• Temperatures above 30 °C during flowering can markedly reduce seed yield.

Fertilization

• Requires a good supply of nitrogen, especially in the early growth stages.

• Phosphorus and potassium are important for root development, flowering, and seed formation.

• Beneficial response to some micronutrients (for example boron), which help reduce flower and pod abortion.

• Balanced fertilization improves oil content, protein content, and overall seed quality.

Crop care

• Early weed control is essential to avoid competition during the first weeks.

• Crop rotation is strongly recommended to limit diseases typical of Brassicaceae (e.g. clubroot, sclerotinia).

• Regular monitoring for pests such as flea beetles, aphids, and lepidopteran larvae.

• Avoid excessive plant density: adequate spacing improves plant vigour and final yield.

Harvest

• Performed when pods are mature but not overly dry, to limit shattering losses.

• Ideal seed moisture: roughly 8–10%.

• Mechanical harvesting is standard practice.

• Proper timing and combine settings reduce losses due to pod dehiscence and seed scattering.

Propagation

• Propagated by seed.

• Autumn sowing for winter varieties; spring sowing for spring types, depending on the region.

• Certified seed is recommended to ensure varietal purity and consistent agronomic performance.

Indicative nutritional values per 100 g (canola oil)

Typical values for refined canola oil:

• Energy: ~884–900 kcal

• Water: 0 g

• Protein: 0 g

• Total carbohydrates: 0 g

  • Sugars: 0 g

  • Fibre: 0 g

• Total fat: ~100 g

  • First occurrence of lipid acronyms: SFA (saturated fatty acids, which may be undesirable if chronically excessive), MUFA (monounsaturated fatty acids, generally favourable for cardiovascular profile), PUFA (polyunsaturated fatty acids, important for inflammatory balance and cardiovascular health). Later mentions of these acronyms will appear without bold.

  • SFA: ~6–7 g (≈6–7 %)

  • MUFA: ~60–65 g (≈60–65 %, predominantly oleic acid)

  • PUFA: ~25–30 g

    • Omega-6 (linoleic acid): ~17–21 g

    • Omega-3 (alpha-linolenic acid): ~7–11 g

  • Natural trans fats: ~0.3–0.5 g (physiological low level)

• Cholesterol: 0 mg

• Sodium: 0 mg

• Vitamin E (total tocopherols): ~18–25 mg

• Other vitamins: negligible

Key constituents

• Triglycerides

  • Oleic acid (C18:1, ω-9) as the main component

  • Linoleic acid (C18:2, ω-6)

  • Alpha-linolenic acid (C18:3, ω-3)

  • Saturated fatty acids (palmitic, stearic) in low proportion

• Unsaponifiable fraction

  • Phytosterols (e.g. β-sitosterol, campesterol, brassicasterol)

  • Tocopherols (vitamin E, mainly γ- and α-tocopherol)

  • Traces of carotenoids and other minor antioxidant compounds

• Technological/minor components

  • Possible traces of added natural antioxidants (e.g. tocopherol concentrates) in some commercial oils

Production process

• Raw material

  • Canola seeds (low-erucic-acid, low-glucosinolate rapeseed varieties), dried and cleaned.

• Oil extraction

  • Cleaning, partial dehulling and crushing of the seeds.

  • Mechanical pre-pressing to obtain a first fraction of oil.

  • Optional solvent extraction (commonly hexane) of the remaining oil from the press cake, following good manufacturing practices.

• Refining (RBD oil: refined, bleached, deodorised)

  • Degumming (removal of phospholipids).

  • Neutralisation (removal of free fatty acids).

  • Bleaching (adsorption of pigments on bleaching earths).

  • Deodorisation (steam distillation under vacuum to remove volatile odorous compounds).

  • Verification that erucic acid and other undesirable components are within strict regulatory limits.

• Packaging

  • Final filtration and bottling in suitable containers (glass or barrier PET) under conditions that minimise oxygen, light and heat exposure.

Physical properties

• Physical state: liquid at room temperature.

• Colour: pale yellow to golden.

• Odour: mild, characteristic but not strong.

• Smoke point (refined): typically around 220–230 °C (quality-dependent).

• Density at 20 °C: ~0.91–0.92 g/mL.

• Iodine value: high (typical of oils rich in unsaturated fatty acids).

• Oxidative stability: good for a highly unsaturated oil, thanks to the prominent MUFA fraction and natural tocopherols, but still sensitive to light, heat and oxygen.

Sensory and technological properties

• Flavour: delicate, neutral or slightly “seedy”, non-dominant.

• Aroma: light, suitable when the oil should not overshadow other flavours.

• Mouthfeel: provides a soft, smooth sensation, useful both raw and in cooked preparations.

• Behaviour in cooking

  • Good stability for frying and high-temperature cooking if the smoke point is respected and reuse is controlled.

  • Less prone to oxidation than very PUFA-rich oils such as conventional soybean or sunflower oil.

• Technological functionality

  • Lipid phase in emulsions (mayonnaise, sauces, dressings).

  • Carrier for lipid-soluble flavours and bioactives.

  • Contribution to texture and softness in baked goods and spreads.

Food applications

• Cold use: salad dressings, marinades, drizzled over vegetables, grains or cold dishes.

• Cooking: sautéing, pan-frying, roasting and baking.

• Frying: domestic and industrial frying (chips, battered and breaded products, snacks), especially with high-oleic canola varieties.

• Spreads and margarines: in combination with other oils and fats.

• Bakery: breads, buns, focaccias, cakes, biscuits, crackers and savoury snacks.

• Emulsions and sauces: mayonnaise, creamy dressings, vinaigrettes.

• Infant and clinical nutrition: when a neutral-flavoured oil with a favourable fatty-acid profile is required (within specific regulatory frameworks).

Nutrition and health

• Fatty-acid profile

  • The low SFA and high MUFA content are clear advantages relative to many other fats, generally supporting improved blood lipid profiles when canola oil replaces fats rich in saturates.

  • PUFA include both omega-6 (linoleic) and omega-3 (alpha-linolenic); the presence of omega-3 distinguishes canola from oils that are almost devoid of them.

• Essential fatty acids

  • Provides both linoleic acid (ω-6) and alpha-linolenic acid (ω-3), which are essential and must be supplied by the diet.

• Vitamin E

  • Naturally occurring tocopherols contribute to antioxidant defence and help protect polyunsaturated fatty acids from oxidation; nutritionally they support protection of cell membranes.

• Risks from excessive intake or misuse

  • Like all fats, canola oil is energy-dense; overconsumption can contribute to excessive caloric intake, weight gain and metabolic complications.

  • Incorrect use (very high frying temperatures, prolonged and repeated heating, poor storage) can lead to formation of oxidation products and degradation compounds that are undesirable for health and sensory quality.

• Erucic acid content

  • Canola varieties are selected for very low erucic acid content, and commercial canola oil has to comply with stringent maximum limits established by international regulations.

Portion note

• Typical dietary use: about 10–20 g per day as a condiment (roughly 1–2 tablespoons) is a reasonable amount for an average adult, to be evaluated in the context of total daily fat and energy intake.

Allergens and intolerances

• Canola does not belong to the major allergenic food groups listed in European regulations; allergic reactions to refined canola oil are rare.

• Highly refined oil contains only trace amounts of proteins, which further reduces the risk of reactions compared with whole seeds.

• In individuals with known allergy to rapeseed/mustard or other Brassicaceae, caution and medical advice are recommended.

Storage and shelf-life

• Storage

  • Keep in a cool, dry place, protected from direct light and heat sources.

  • Always close the bottle tightly after use to limit contact with air.

• Shelf-life

  • Typical shelf-life: about 12–18 months for properly refined and bottled oil; always check the best-before date.

• Signs of deterioration

  • Rancid or paint-like odour, unpleasant flavour, abnormal darkening; if these appear, the oil should be discarded.

Safety and regulatory aspects

• Canola oil (low-erucic rapeseed oil) is generally recognised as safe for human consumption by major health authorities when produced under good manufacturing practices.

• There are strict regulatory limits for the maximum erucic acid content in edible oils and fats.

• In some producing countries, a portion of the canola crop is genetically modified (GM) for agronomic traits or lipid profile, which implies specific labelling obligations depending on local legislation.

Labelling

• Typical ingredient names

  • “Canola oil” or “low-erucic acid rapeseed oil”, depending on the market and regulatory context.

• GMO information

  • Where GM varieties are used, this must be declared according to GMO labelling rules (e.g. in the EU).

• Possible claims

  • “High in unsaturated fat” or similar, when legal conditions are met.

  • “Source of omega-3” only if the alpha-linolenic acid content per portion satisfies the relevant criteria.

• Cholesterol

  • Being a vegetable oil, canola oil contains no cholesterol; this may be indicated in line with regulations on nutrition claims.

Troubleshooting

• Problem: Oil turns rancid quickly

  • Possible causes: storage in warm, bright places; frequent exposure of a large bottle to air; poor packaging.

  • Corrective actions: store in a cool, dark location; choose dark glass or barrier PET; use smaller formats if consumption is low; keep the cap tightly closed.

• Problem: Excessive smoke and strong odour during frying

  • Possible causes: frying temperature too high, presence of burnt food residues, repeated and prolonged reuse of the same oil.

  • Corrective actions: control temperature, filter the oil between uses, limit the number of reuses, replace oil when it darkens significantly or develops off-odours.

• Problem: Fried products too greasy or soggy

  • Possible causes: frying temperature too low, overloading the fryer, batters too wet.

  • Corrective actions: maintain the correct frying temperature, fry in small batches, drain or pat dry foods before frying.

Sustainability and supply chain

• Cultivation

  • Canola is a major oilseed crop in many regions (e.g. Canada, parts of Europe), playing an important role in crop rotations and potentially supporting soil health and diversification when properly managed.

• Environmental impact

  • The impact depends on farming practices (fertiliser and pesticide use, soil management). Integrated or organic systems can reduce environmental footprint.

• GM varieties and traceability

  • Use of GM canola calls for robust traceability and segregation systems along the supply chain; certified non-GMO or organic options are available for specific market segments.

• By-products

  • Canola meal and protein-rich cakes are widely used in animal feed, contributing to circularity and full valorisation of the crop.

Main INCI functions (cosmetics)

In cosmetic products the oil typically appears as Canola Oil or related derivatives (e.g. Canola Oil Unsaponifiables):

• Emollient / skin conditioning: softens and smooths the skin, helping to reduce transepidermal water loss.

• Hair conditioning: improves hair slip and shine in oils, conditioners and masks.

• Lipid vehicle: solubilises lipophilic actives (vitamins, botanical extracts) in massage oils, body oils and bath oils.

• Unsaponifiable fraction: used in anti-ageing and barrier-support formulations thanks to phytosterols and tocopherols.

Conclusion

Canola oil is a modern, technically optimised lipid source derived from rapeseed varieties bred for improved composition. Its fatty-acid profile, characterised by low saturates, high monounsaturates and meaningful amounts of plant omega-3, together with a good vitamin E content, makes it an interesting ingredient in strategies targeting cardiovascular health when used in place of more saturated fats and within an overall balanced diet. From a technological and sensory point of view it offers a mild flavour, wide culinary versatility and adequate frying performance when handled correctly. In cosmetics, its emollient and conditioning properties, together with the unsaponifiable fraction, support a broad range of skin and hair formulations. A supply chain managed with attention to agronomic practices, environmental impact and traceability (including GM aspects where relevant) allows the benefits of this ingredient to be maximised across food and personal care sectors.

Mini-glossary

• SFA – Saturated fatty acids; a class of fats which, when consumed in excess, can raise LDL cholesterol and increase cardiovascular risk.

• MUFA – Monounsaturated fatty acids; fats that can improve blood lipid profiles when they replace saturated fats in the diet.

• PUFA – Polyunsaturated fatty acids; include omega-6 and omega-3 families, important for membrane structure, inflammatory balance and cardiovascular health.