The analysis of organically bound elements (As, Se, Br) and phosphorus in raw, refined, bleached and hydrogenated marine oils produced from fish of different quality

Abstract

Marine oils have been produced in pilot plant by boiling, pressing and separation of the press liquor from raw material (mackerel and herring) of different levels of spoilage. The difference in quality is obtained by varying the period of storage. Some of the oil samples have been refined and hydrogenated. In samples taken both from the raw oils and from oils at the different steps in the processing, organic bound arsenic, selenium, bromine and phosphorus are analyzed. When the raw material deteriorates during storage, an increase in the selenium and phosphorus content in the oils produced from these materials is observed, whereas the bromine and the arsenic content is nearly constant. During the refining the arsenic and phosphorus disappear almost completely from the oils, whereas the selenium content is reduced to about two-thirds and the bromine content is nearly unaffected. In the hydrogenation step the selenium disappears relatively fast and the bromine more slowly.