modification, would be well adapted for use as a rapid drjrLng oil in 

 the manufacture of enamels or lacquers. Salmon livers contain only a 

 small amount of oil, but they do have a higher vitamin content than 

 the oils prepared from other parts of the waste with the possible ex- 

 ception of the viscera already mentioned above. Samples of salmon 

 liver oils have assayed as high as 40,000 units of vitamin A per gram 

 of oil. 



Percent Composition 



The amount of fat, lipid, or cholesterol present in various parts 

 of salmon cannery waste has not been determined accurately except for a 

 few incomplete reports appearing in the scientific literature. The fat 

 content of the various parts, glands, and organs varies from as low as 

 1 to 4 percent oil in salmon milt to as high as 22 percent fat in salmon 

 roe. These oils also differ in composition as regards the amount of un- 

 saturated acids present, the amount of lecithin and the percent of 

 cholesterol. Koenig and Grossfeld (8) reported that the fat from fish 

 roe contains as high as 49 percent lecithin and from 4 to 14 percent 

 cholesterol. Schmidt-Nielsen and coworkers (11) reported in 1943 that 

 cholesterol was present in fish sperm to the extent of 10-25 percent of 

 the total fat. A report by Anno (2) in 1940 stated that the total unsa- 

 ponifiable matter present in the lipids of salmon eggs was essentially 

 cholesterol. Research by Harrison, et al (5) on Pacific salmon oils showed 

 that the oil from salmon eggs has an iodine number as high as 220 indi- 

 cating a large content of highly unsaturated fatty acids. 



Sorting Problems 



The recovery of a general purpose fish oil from total salmon cannery 

 waste would require no sorting. The production of special oils or other 

 lipids from various parts or organs would, of course, involve some 

 sorting. The degree of sorting needed would depend on the nature and 

 required degree of purity of the product or products to be recovered. 

 Again, as mentioned in a previous section, mechanical separation might be 

 sufficient to furnish the material for extraction. It is believed that 

 salmon eggs at least might be handled separately , to an economic ad- 

 vantage, so as to recover a high quality protein material as well as to 

 obtain the fat which should be highly valuable for its content of both 

 lecithin and highly unsaturated fatty acids. 



Manufacturing Difficulties 



The extraction and isolation of special fractions of the fats and 

 lipids present in salmon cannery waste would encounter some difficulties 

 not met with in processing most vegetable tisr>ues. The ordinary reduction 

 of entire waste results in a dark colored oil which has undergone con- 

 siderable decomposition. This comparatively low grade oil has not found 

 wide usage except in possibly the leather and soap industries. Solvent 

 extraction methods mii:!;ht be adaptable to certain portions of the waste 

 such as salmon egr.s. Naturally, this t^-pe of processing equipment is com- 

 paratively expensive and requires a considerable amount of technical 



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