A Method of Enhancing the Vitamin A Value of Cod Liver Oil

Abstract

Some unpublished data kindly supplied to the authors by Dr. Walter H. Eddy have indicated that cod liver oil in an emulsified form is a more efficient source of the fat soluble vitamins than plain cod liver oil. Recent comparisons in this laboratory of the vitamin values of emulsified vs. plain cod liver oil yield results in accord with those obtained by Eddy, and show quite conclusively that the emulsified cod liver oil which we have examined is a decidedly more efficient source of vitamin A than the same oil in the unemulsified state. The particular type of emulsion which has interested us is the same as that employed by Eddy in his earlier investigations, and consists of 22.37% by weight of high grade cod liver oil with 77.63% of concentrated malt extract. Emulsification of these constituents is effected by thoroughly agitating the cod liver oil and the malt extract in an especially constructed apparatus operated under reduced pressure. A fine emulsion results, with the oil uniformly distributed in the aqueous phase as minute droplets microscopic in size. While other tests have shown that the malt extract itself contains relatively little vitamin A, it was thought that some factor or factors present in the extract, such as vitamin B or G, might exert a synergistic action of some kind upon the vitamins of cod liver oil and thus increase their effectiveness. We have, therefore, included not only a study of the vitamin A value of the plain as well as the emulsified cod liver oil, but also that of a mixture of the malt extract and cod liver oil. Sherman's method for determining vitamin A was employed. When young rats fed the vitamin A-free diet had ceased to grow and showed by other symptoms that their surplus bodily stores of this vitamin were depleted, they were divided into 3 groups.