When salmon eggs are ccanpared with certain other materials as a 

 potential source of cholesterol, they appear to be someviiat inferior. 

 For instance, the spinal cords of meat animals are comparatively high 

 in cholesterol content and are recovered for cholesterol production 

 at some of the larger meat packing centers. The yield of pure choles- 

 terol from spinal cords amounts to 3.0 to 3»5 percent of the fresh tis- 

 sue. Upon the basis of our experimental findings, it can be seen that 

 the cholesterol content of the spinal cords is about 8 to 10 times great- 

 er than that of salmon eggs. A compensating factor, however, is that 

 the recovery of the spinal cords from the carcasses of meat animals 

 might be somewhat more costly than the collection of salmon eggs. 



To examine the problem further upon £in econc»uic basis, we can, by 

 calculation, arrive at the probable value of salmon eggs as a source of 

 cholesterol. From the experimental results using the cholesterol value 

 of 0.40 percent, it cam be readily calculated that, presuming the optimal 

 recovery, about 250 pounds of raw salmon eggs would yield one povutid of 

 cholesterol. At the present price of $12.00 per pound, the cholesterol 

 recoverable from one pound of salmon eggs would be valued at about five 

 cents. To this, of course, must be added processing costs. Unless a 

 profitable recovery of protein, fat and possibly lecithin could be ac- 

 complished from the same material, it seems unlikely that salmon eggs 

 could be profitably processed for their cholesterol content. 



Protein. Fat and Lecithin Recovery 



In order to obtain the salmon egg protein in a fat-free form, as 

 well as to recover the fat itself, an extraction process was developed 

 using acetone directly on the raw salmon eggs. In this process the 

 acetone removes the water content of the egg and a major portion of the 

 fat. Final extraction of some of the lipoidal material is accomplished 

 with hot ethanol. By distillation of the acetone-water-fat solution at 

 atmospheric pressure, the solvent is recovered and the oil or fat sep- 

 arates as a layer on top of the water in the still pot. The oil is then 

 separated from the water by decantation. 



Before commencing pilot plant studies of the solvent extraction 

 process, it was decided to determine the proximate analysis of eggs from 

 various species of salmon. Table 4 presents the analytical results ob- 

 tained using the A.O.A.C. V Methods of Analysis on the raw salmon eggs. 

 The samples of the various species used for analysis were from the same 

 containers as those used for cholesterol determinations presented in 

 Table 1, page 19. 



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