Colza oil is a nondrying oil obtained from the seeds of brassica rapa, var. Oleifera, a variety of the plant that produces turnips. Colza is extensively cultivated in france, belgium, the united states, the netherlands and germany and poland. In france, especially, the extraction of the oil is an important industry. It is a comparatively nonodoriferous oil of a yellow colour, having a specific gravity varying between 0.912 and 0.920. The cake left after extraction of the oil is a valuable feed ingredient for pigs.