For centuries, rapeseed oil was characterized by its high content of cis-docos-13-enoic acid, which not only acted as a barrier to human nutrition (pathological changes to the myocardium and adipose degeneration of the heart), but also harmed animal health (decreased appetite, weight reduction, increased thyroid gland). It was not until rapeseed varieties with a lower cis-docos-13-enoic acid content were cultivated, that humans could use rape oil for dietary purposes (in 1973 the Bundessortenamt [German federal plantation agency] authorized the first variety with a low acid content cis-docos-13-enoico).
Crude oil is obtained by purifying the crushed seeds (with oil content of 30-40%), which are subsequently subjected to heat treatment, peeling, conditioning (deactivation of lipase, mirosinase and thioglucosidase), pressed and / or squeezed. Crude oil is subsequently refined. Light-brown, brownish-yellowish rapeseed oil thus obtained consists mainly of palmitic, oleic, linoleic, and linolenic acids, which provide a weak odor, with no taste or a slightly bitter taste. Rapeseed oil is used (increasingly) as table oil, as a fat stabilizer, in the production of margarine and as a mineral oil additive. It acts as a raw material in the production of facticio (elastic mass for rubber goods), insecticides, wax grafts, plasters, as a greasing agent of leather and is a raw material for the production of biological diesel (rapeseed methyl ester). In the pharmaceutical sector, rapeseed oil is used, among others, as a filling for soft gelatin capsules. Since “old” rapeseed oil, with its high cis-docos-13-enoic acid content, is a source rich in C20 and C22 fatty acids (industries manufacturing plastics and detergents), these rapeseed varieties become to grow on a large scale.