Rex Baradi of Dunedin asks :-
What is Canola Oil, as used in cooking?
Rufus Turner, a biochemist at Crop and Food Research, responded.
Canola oil is also known as rapeseed oil. The plant is a member of the brassica family, which also includes turnips, mustard and cabbages. The rape/canola plant is tall, up to 2 metres high, with lots of yellow flowers. The oil comes from crushing the seeds in the pods.
Canola is a made up name derived from Canadian and Oil (with Low Acid added on (LA).
It has a very low saturated fatty acid composition (about 5 percent), is high in monounsaturated fatty acids (55-60 percent) and 20-25 percent n-6 and 15-20 percent n-3 polyunsaturated fatty acids (PUFA) so can be a healthy oil to use for frying (it has a relatively high smoke point) or in general processed food. Due to its relatively high PUFA levels, the oil can oxidise rapidly if it is stored in clear plastic bottles exposed to sunlight.
The n-6 to n-3 PUFA profile is thought to be one of its high selling points as n-3 PUFAs are not often found in as high a concentration in plant based oils. However almost all of the n-3 oil is in the 18:3 form which is not as readily absorbed as other n-3 PUFAs.
Overall it is a relatively healthy frying and processing oil to use and is pretty cheap to purchase. Other oils that have higher smoking points include rice-bran oil and avocado oil (both cost a lot more at present). Other oils which are relatively cheap and have similar or better smoking point temperatures include sunflower oil, peanut (groundnut) oil and safflower oil. It is better than butter, margarine and olive oil. These all refer to refined oils. Canola oil has very little taste, which can be good for frying if no added taste is wanted.
As far as I am aware virtually all the canola oil in New Zealand will be imported. Canola oil was developed prior to genetic engineering of plants and hence may be labelled as 'Canola oil but not GE'. If you are concerned about the origin of any canola oil you buy it would be worth investigating which type it is.