Rapeseed is a yellow flowering plant in the Brassicaceae family, grown mainly for its oil-rich seeds, the third largest source of vegetable oil in the world. Rapeseed oil was produced in the 19th century as a source of lubricant for steam engines, as it was less useful as feed for animals or humans, as it has a bitter taste due to high levels of glucosinolates. Today, varieties have been bred to reduce the glucosinolate content, resulting in a more palatable oil. This has had the side effect that the oil contains much less erucic acid. Today, rapeseed is grown for the production of animal feed, vegetable oil for human consumption and biodiesel. World rapeseed/canola production increased to 47 million metric tonnes in 2006, of which total EU-25 production is 16 million metric tonnes. Rapeseed contains from 40 to 52% low-sugar oil, up to 20% protein and 17% carbohydrates. The nutritional qualities of rapeseed oil are determined by its oil-acid composition. It contains vitamins A, E, K and D, phosphates and tocopherols. Approximately 85% of rapeseed oil composition is essential fatty acids – Linoleic 20% and 65% oleic acid. The processing of rapeseed for oil production provides rapeseed meal as a by-product. The by-product is an animal feed with a high protein content. The feed is mainly used for cattle feed, but also for pigs and poultry (although less valuable for poultry).