If you have ever driven through Germany in May, you may have noticed large fields of bright yellow plants along the Autobahns. These are fields of rapeseed blooming, an important crop for Germany. Drive through a few weeks later and they are gone. Why? Because they have set seed and turned brown, ready for harvest.
Rapeseed oil is extracted from the "Raps" or rape (Brassica napus or Brassica rapa subsp. oleifera) plant, specifically the seeds. It is a very common crop in Germany with 1,300,000 hectares planted in 2011. It has been cultivated and used by humans for thousands of years in India and since the Middle Ages in Europe, mostly for lamp oil, to make soap and later to lubricate engines. It was eaten during famine times and during both World War I and World War II, Germany made margarine out of it.
Up to 1974, rapeseed oil was used very little in the food industry, the rest was used in machine and chemical industries. Then, through selective breeding programs in German universities, the bitter-tasting, toxic substance, erucic acid, was reduced to a level that was safe for human consumption in winter rapeseed. Later, in Canada, summer rapeseed was found with low levels of the acid and further research picked out plants with low levels of glucosinolates as well.
Rapeseed today is used to make biodiesel, margarine, animal feed and bioplastics. A type of edible rapeseed oil is called canola, which was bred in Canada in the 1970s. Canola stands for Canadian oil, low acid but is now used generically to mean edible rapeseed oil. Rapeseed 00 is the term for one genetically modified type of edible rapeseed.
Canola oil contains omega-6 and omega-3 fatty acids and is high in monounsaturated fats. It is considered a healthy oil for cooking by many people. It is liquid at room temperature, neutral-tasting and can be used for cooking at medium heat and in cold dishes as a dressing or marinade.
Rapeseed is related to mustard, turnips and other cabbage plants. It is pollinated by honeybees and the honey is mixed with other types or sold as bakery-grade.