Is it true that in China, rapeseed oil was found to emit harmful emissions when heated?
Yes. However, the study also found that other vegetable oils tested in China produced the same emissions under the same conditions. Most people in China cook with unrefined rapeseed oil, which is not processed to remove contaminants and contains no antioxidants. Temperatures during wok cooking in China are about 100o F (38oC) higher than those used in Canada and the U.S. This combination of frying with unrefined rapeseed oil at very high temperatures (to the point where the oil produces a thick, black smoke) can produce harmful emissions. Consumers in other countries use more refined vegetable oils– never rapeseed oil – at much lower cooking temperatures. These two factors prevent these emissions. All vegetable frying oils used in Canada and the U.S. (and many other countries) are refined and frequently contain antioxidants which help prevent harmful emissions during frying.
