Cod liver oil
|
This article needs attention from an expert on the subject. Part or all of this article has been imported from the 1911 edition of the Encyclopaedia Britannica, which is now free of copyright and hence in the public domain. The imported text may be significantly out of date, and any more recent developments may be completely missing |
|
Cod liver oil, formerly known in medical Latin as Oleum Morrhuae or Oleum Jecoris Aselli, is the oil obtained from the liver of the common cod. It is high in Vitamins A and D, and also contains Omega-3 fatty acids, and various health benefits have been attributed to it. It is widely available in high street chemists.
A century ago, the most important centres of the cod-liver oil industry are Lofoten and Romsdal in Norway; the oil is also prepared in the United States, Canada, Newfoundland, Iceland and Russia; and at one time a considerable quantity was prepared in the Shetland Islands and along the east coast of Scotland.
Preparation
In the early process for extracting the oil the livers were allowed to putrefy in wooden tubs, when oils of two qualities, one called "pale oil", and the other "light brown oil", successively rose to the surface and were drawn off. A third oil was obtained by heating the liver-residues to above the boiling-point of water, whereupon a black product, technically called "brown oil", separated. The modern practice consists of heating the perfectly fresh, cleaned livers by steam to a temperature above that of boiling water, or, in more recent practice, to a lower temperature, the livers being kept as far as possible from contact with air.
The oils so obtained are termed "steamed-liver oils". The "pale" and "light brown" oils were used in pharmacy; the "brown" oil, the cod oil of commerce, being obtained from putrid and decomposing livers, has an objectionable taste and odour and was largely employed by tanners. By boiling the livers at a somewhat high temperature, "unracked" cod oil can be obtained, containing a considerable quantity of "stearine"; this fat, which separates on cooling, was sold as "fish stearine" for soap-making, or as "fish-tallow" for currying.
The oil when freed from the stearine was known as "racked oil." "Coast cod oil" was the commercial name for the oil obtained from the livers of various kinds of fish, e.g. hake, ling, haddock, etc.
External Links
References
This article contains text from the article Cod-liver oil in the 1911 Encyclopædia Britannica <references/>
