Variations Made in Procedure for Alkali Digestion 



In conjunction with the preparation of samples of oil from the waste 

 for each of the species of salmon, variations were made in the technique 

 of the digestions in an attempt to improve the method and at the same 

 time to concentrate the vitamin A recovery into as small a volume of oil 

 as possible. 



Processing salmon livers alone 



In one experiment the salmon livers were collected separately for an 

 alkali digestion. As had been expected, there was no oil recovered upon 

 centrifuging. The total liquor from the centrifuge was saved and salmon 

 head oil of known vitamin A content was agitated with this hot liquor to 

 oil-solvent extract any vitamin A that might be present. 



Digestion of total viscera 



As was described in the section on "Collection of Raw Materials", 

 conmercial operations on salmon cannery waste might have to be predicated on 

 the use of the waste material as it comes from the "Iron Chink". Since 

 the head-collar section could be separately conveyed from the header as 

 mentioned earlier, the balance of the waste would then be available for 

 processing into vitamin A bearing oil. Representative lots of this total 

 viscera were alkali digested in exactly the condition they were discharged 

 from the machine. Precautions previously taken to wash out blood, sea- 

 water, coagulated egg materials, etc., with fresh water prior to the digestion 

 were dispensed with. 



Removal of both gonads 



Earlier studies of the vitamin content of salmon waste by Harrison (2) 

 have *own that although the salmon eggs do contain approximately 7 per- 

 cent of oil, the vitamin A content is considerably less than 500 U. S. P. 

 units per gram of oil. One would not expect the male gonads or testes to 

 contain any more vitamin A that the eggs because of the specialized nature 

 of the organs. Both these sexual products were, therefore, sorted fnMn the 

 viscera and discarded as diluents of the raw material. Digestions made 

 on material thus sorted were said to be from "viscera less gonads". 



T2} Harrison, R. W.; Anderson, A. W. ; Holmes, A. D.j and Pigott, M. G. 

 Vitamin content of oils from cannery trinmings of salmon from the Columbia 

 River and Puget Sound regions. Investigational Report No. 36, U. S. 

 Bureau of Fishe ries. 1937. 



Removal of the testes from the waste 



The soft portion of the waste contains the male gonads or testes. The 

 mature testes are comp>osed, in large measure, of protein and water. Since 



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