Chemical Properties
Yellow-brown liquid.
Production Methods
Canola oil is obtained by mechanical expression or n-hexane
extraction from the seeds of Brassica napus (Brassica campestris)
var. oleifera and certain other species of Brassica (Cruciferae). The
crude oil thus obtained is refined, bleached, and deodorized to
substantially remove free fatty acids, phospholipids, color, odor and
flavor components, and miscellaneous nonoil materials.
Pharmaceutical Applications
Canola oil is a refined rapeseed oil obtained from particular species
of rapeseed that have been genetically selected for their low erucic
acid content. In pharmaceutical formulations, canola oil is used
mainly in topical preparations such as soft soaps and liniments. It is
also used in cosmetics.
Safety
Canola oil is generally regarded as an essentially nontoxic and
nonirritant material, and has been accepted by the FDA for use in
cosmetics, foods, and pharmaceuticals.
Rapeseed oil has been used for a number of years in food
applications as a cheap alternative to olive oil. However, there are
large amounts of erucic acid and glucosinolates in conventional
rapeseed oil, both substances being toxic to humans and animals.
Canola oil derived from genetically selected rapeseed plants that are
low in erucic acid content has been developed to overcome this
problem. The FDA specifies 165.55 mg as the maximum amount for
each route or dosage form containing the ingredient.
Feeding studies in rats have suggested that canola oil is nontoxic
to the heart, although it has also been suggested that the
toxicological data may be unclear.
storage
Canola oil is stable and should be stored in an airtight, lightresistant container in a cool, dry place. The USP32–NF27 specifies that contact between canola oil and metals should be avoided. Containers should be filled to the top, while partially filled containers should be flushed with nitrogen. During storage, grassy, paintlike, or rancid off-flavors can develop.
Flavor deterioration has been attributed mainly to secondary oxidation products of linolenic acid, which normally makes up 6–14% of the fatty acids in canola oil. Storage tests of canola oil showed sensory changes after 2–4 days at 60–658℃ in comparison to 16 weeks at room temperature. Canola oil seems to be more stable to storage in light than cottonseed oil and soybean oils, but is less stable than sunflower oil. In addition, the effects of various factors on sediment formation in canola oil have been reported.
It has been reported that oils stored at 28℃ showed the highest rate of sediment formation, followed by those stored at 68℃. All samples showed little sediment formation, as measured by turbidity, during storage at 128℃. Removal of sediment from canola oil prior to storage by cold precipitation and filtration did not eliminate this phenomenon, which still developed rapidly at 28℃.
A study on the effect of heating on the oxidation of low linolenic acid canola oil at frying temperatures under nitrogen and air clearly showed that a significantly lower development of oxidation was evident for the low linolenic acid canola oil. Reduction in the linolenic acid content of canola oil reduced the development of room odor at frying temperatures.
The thermal oxidation of canola oil studied during oven heating revealed an increase in peroxide values of pure and antioxidant- treated oils. Peroxide values were shown to differ between pure and antioxidant-treated canola oil during the initial stages of microwave heating (6 minutes). Formation of secondary products of oxidation, which contribute to off-flavors, were also observed.
Regulatory Status
Accepted for use by the FDA in cosmetics and foods. Included in the
FDA Inactive Ingredients Database (oral capsules). Included in the
Canadian List of Acceptable Non-medicinal Ingredients.
