Undersøkelser av produksjonsprøver av medisintran 1937 til 1946

Abstract

437 samples collected from the Norwegian cod liver oil production in the years 1937 to 1946 have been examined for blue value, free fatty acid, Kreis value and refractive index. In addition other data such as weight of the fish, their liver content and their oil yields are given. From these samples, 156 representative composite samples were analysed for the above constants as well as for E (10g /l)/328, iodine value, saponification value, unsaponifiable matter, and colour. Calculations of the vitamin A content were made both as BV/g whole fish and as mg vit. A/kg whole fish. It is shown that the amount of vitamin A in the livers is fairly constant for mature cod in Lofoten, Vesterålen, Senja, Troms and Møre. Size and age of the fish have no apparent effect on the quantity of vitamin A in the fish. For the bulk of the landings (Lofoten fish) the variation in the annual average in vitamin A content during these years was 13,3 to 16,0 mg vit. A/kg fish, or ± 9 %. The vitamin content of a given sample of oil depends on the liver content of the fish, and on the percent of oil in the livers. The oil acts as a diluent for vitamin A, and fish yielding much oil give low potency oils, while fish yielding less give oils containing more vitamin A. For Lofoten, the annual average for vitamin A content of the oil varied from E = 0,46 to 0,83 or from 740 to 1330 IU/g in these years. For immature cod, caught off the coast of Finnmark, the size of the fish has a marked influence on the vitamin A content. Small fish yield oils of lower potency than larger ones. The average vitamin A content in these immature fish has, in the years investigated, varied from 6,2 to 12,2 mg vit. A/kg of fish, and the vitamin A content of the oils has varied from E = 0,30 to E = 0,60. Tables and figures are given for the average liver and oil content of the fish, and for the vitamin A, unsaponifiable matter and iodine values of the oils. The percent of unsaponifiable matter in the oils was found to increase with increased vitamin A content. The average iodine values of oils from mature fish showed only small variations from one year to another, but those for oils from immature fish from Finnmark varied from 151 to 169.