14 U.S. BUREAU OF FISHERIES 



value of drying oils in paints. Where fish oils are used for other than 

 their drying properties, their ability to take up oxygen proves a 

 handicap since oxidation leads to tliickening and the acquiring of an 

 undesirable odor and taste. When oils are winterized or cold pressed 

 in order to give them the property of remaining fluid and clear at 

 low temperatures, the proportion of unsaturated fatty acids to satu- 

 rated fatty acids is increased, with the resultant tendency for them to 

 have a greater faculty for taking up oxygen. Certain chemical 

 compounds, when mixed with an oil of this nature, have the ability 

 to retard oxidation. These are known as antioxidants or inliibitors, 

 and should have usefulness in stabilizing the keeping properties of 

 fish oils in certain uses. With this in mind, the Bureau has under- 

 taken an investigation of the use of antioxidants in fish oils. The 

 work which has just begun will be continued during the coming year. 



NUTRITIVE VALUE OF FISHERY PRODUCTS 



Since we are dealing fundamentally with a food industry and, there- 

 fore, since our technological investigations constitute a higiily special- 

 ized field of food research, obviously the nutritive or food value of 

 fishery products is of primary importance. This applies not only to 

 the fishery products of current commerical importance, but also ap- 

 plies to any experimentally manufactured products resulting from 

 studies of improvements in manufacture, preservation, handling, 

 storage, and marketing. In other words, the consumer is not 

 only interested in the fishery products now on the market and avail- 

 able for human nutrition and in the byproducts now available for 

 animal nutrition, but he is interested in any improvements that can 

 be made in these products by experimental work. It naturally fol- 

 lows that quality and increased food value are the measurements of 

 any improvements which can be made in the products of tliis industry. 

 For this reason, our nutrition experiments play an extremely important 

 and vital role in our program of technological investigations, viewing 

 these integrated phases of our technological program as a coordinated- 

 whole. Therefore, our nutrition tests serve two important functions. 

 The first function of nutrition studies is to determine the quality and 

 food value of current fishery products of commerce. The second 

 function of this work is to provide a yardstick for evaluating improve- 

 ments in methods of manufacture, preservation, handling, storage, 

 and marketing, in terms of the quahty and food value of the finished 

 products of these experimental methods as compared with the finished 

 products of commercial methods now in use. 



During the past year various phases of our program of nutrition 

 research were carried out in our laboratories in ^\ashington, D.C., 

 and in the State laboratory at Charleston, S.C., by the following mem- 

 bers of our technological stafl": E. J. Coulson, Charles F. Lee, and 

 C. D. Tolle. 



SWORDFISH-LIVER OIL 



Recently the Bureau announced in a press release the results of 

 studies made by members of its technological staff in connection with 

 the vitamin content of swordfish-liver oil and the developments of 

 methods of production of swordfish-liver oil of high vitamin potency. 

 This work was performed in the Division's technological laboratories 



