The data show that the rats on the diet containing salmon egg 

 protein grew about as well as those fed casein. No gross symptoms 

 of toxicity were manifested at the termination of the experiment. 

 While it is realized that these experiments are not extensive, 

 they do indicate that no acute toxicity resides in the defatted 

 salmon meal and that its nutritiona.l value is very nearly equivalent 

 to that of casein. 



Further investigations to delineate more precisely the special 

 values of salmon egg protein are now being contemplated. 



Recovery of Salmon Egg Fat. 



The solvent in the acetone-water solution of salmon egg extract- 

 ives was removed by distillation in a simple pot still at atmospher- 

 ic pressure, and the major part of the acetone recovered by heating 

 the mixture to 60 C. From all appearances this temperature was not 

 measurably destructive to the lipide fraction i*iich separated out 

 as aji oily layer. This oil layer was removed by decantation and 

 subjected to further solvent removal at reduced pressure. The water 

 phase was discarded after decantation. In pilot plant studies, it 

 would probably be more expedient to remove the last traces of solvent 

 by washing the oil with water and clearing by centrifugation. This 

 treatment would also remove the lecithin fractions from the oil which 

 might make it more desirable for certain purposes. In the labora- 

 tory studies being described here, the final ethanol extract was also 

 concentrated and the extractives added to the previous acetone solu- 

 ble lipides. It was later detennined that the acetone not only ex- 

 tracts the water and essentially all the free oil, but also a con- 

 siderable amount of the combined phospholipides which are not ordi- 

 narily considered soluble in acetone. The final extraction with hot 

 (boiling) ethanol serves to break up the phospholipide and lipide 

 protein complexes to make them more readily extra ctable. The result- 

 ing oil v/as a dark red color. In order to remOTe some of the dark 

 color and to refine the product somewhat, the phospholipides present 

 in the oil were separated out by dissolving the oil in ether and 

 adding acetone until no further precipitate formed. After precipita- 

 tion of the lecithins by two repeated treatments with fresh acetone, 

 the solvent was again removed from the oil layer by distillation. The 

 oil now possessed a light pinkish-red color which e^diibited no ten- 

 dency to darken upon standing. 



The acetone precipitated sludge of phospholipides was purified 

 further by repeated extraction with fresh acetone to remove any 

 residual oil. Some daricening of the product was observed as the 

 pirification steps proceeded due undoubtedly to exposure to air dur- 

 ing the processing steps. This darkening could pixsbably be averted 

 to some extent by processing the lecithin fraction in an inert at- 

 mosphere which would be more easily accomplished on a larger scale 

 operation than on a laboratory experiment. 



76 



