ineffective for this purpose. Preliminary 

 results in research in Bureau programs is 

 beginning to indicate that this belief is 

 false and that tuna and other fish oils may 

 be even more effective in lowering blood 

 cholesterol than are the vegetable oils. 

 These findings when definitely confirmed 

 should be useful in advertising the nutri- 

 tive value of tuna and other fish. They 

 might eventually also result in a new use 

 for fish oils in the pharmaceutical field. 

 Before this can be achieved, however, 

 means for producing such oils without the 

 objectionable fishy flavor will have to be 

 developed. 



In this connection, the experience in 

 testing fish oils for their blood- 

 cholesterol -lowering properties on human 

 patients is interesting. At Rockefeller 

 Institute, volunteer patients were used to 

 assess the effectiveness of different oils 

 in this regard. The patients were given 

 an emulsion of oil with water or orange 

 juice. When the test series reached fish 

 oils, owing to the fishy flavors the num- 

 ber of volunteers dropped nearly to zero 

 and it was a great problem to obtain enough 

 data on the effectiveness of fish oils to 

 give conclusive results. Thus even though 

 fish oils may well prove to be much more 

 efficient than corn oil for this purpose, 

 it is doubtful if fish oils will find 

 therapeutic application until it is pos- 

 sible to reduce or eliminate the fishy 

 flavor. 



Another of the Bureau's basic research 

 programs deals with the chemical cause of 

 fishy odors and flavors in fish and fish 

 oils and means for diminishing it. This 

 is a very fundamental problem of great im- 

 portance to all phases of the fish preserva- 

 tion industry since preservation is 

 undertaken very largely to prevent develop- 

 ment of undesirable fishy flavors and odors. 

 Only last March the Bureau held a one-day 

 conference which some of you attended at 

 Davis to discuss research in this important 

 field. Suffice it to say here that cooper- 

 ative research is under way among the 

 laboratories of the University of California, 

 University of Minnesota, and the Bureau to 

 get at the chemical basis for this type of 

 degradation and to develop remedies. 



Fish Protein 



Protein is perhaps a more important 



constituent of fish than oil, and much basic 

 research is needed to learn more about how 

 fish proteins behave during canning, freez- 

 ing, and other processing steps, to find 

 out more about the nutritive value of fish 

 proteins, and to find new uses for fish 

 proteins. So far, our Bureau programs on 

 protein have delt largely with the nutri- 

 tive value, particularly with reference to 

 fish meal. 



Our basic research in this field which 

 has been carried out at the Poultry Husbandry 

 Departments of the Universities of California 

 and Wisconsin on a cooperative basis, have 

 been aimed at showing just how tuna meals 

 may differ in nutritive value in relation 

 to the type of waste going into the meal 

 or other processing factors. Older research 

 classed fish meals as good or poor depend- 

 ing upon how they behaved when used as the 

 sole protein source in a check feed diet. 

 We have been finding out the reasons some 

 tuna meals were apparently less effective 

 than others. These cases are often related 

 to the meals containing less than optimum 

 amounts of some of the essential amino 

 acids. There is now hope that even some of 

 these poorer meals can be efficiently 

 utilized, now that we know in what way they 

 are deficient, by proper supplementation 

 with feeds containing more of the missing 

 amino acids. 



Other Components 



There are other components of fish 

 which require basic research besides oil 

 and protein. For example, pigments are 

 important since changes during processing 

 will affect color considerably. Bureau 

 research, carried out by Dr. Tappel and 

 Dr. Brown at the University of California 

 at Davis, has been completed on the chem- 

 istry of the normal pigments in tuna and 

 those responsible for green tuna. Our 

 re search has not only revealed the chemistry 

 of the normal and abnormal pigments but 

 also has developed means for at least par- 

 tially controlling these pigment changes 

 and reversing the developed green color back 

 to the normal pink. Although we now under- 

 stand the chemistry of what is going on to 

 change the normal pink color during cooking 

 to the off "green" shades, we still do not 

 know why some tuna are more prone to develop 

 the greening than others. This is a matter 

 for further research. 



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