FISHERY INDUSTRIES OF THE UNITED STATES, 1939 229 
SOLUBILITY OF FISH PROTEINS 
In the normal reduction of fatty fish and fish waste in the manu- 
facture of fish meal and fish oil, approximately 20 percent of the origi- 
nal solid materials passes into solution and is discarded with the waste 
waters. Because of the importance of this loss, both from the stand- 
point of economical operation and conservation of raw materials, the 
Bureau has begun a study of the solubility of fish proteins during 
cooking in order to determine the possibility of treatment which 
would decrease the amount of material passing into solution. 
NUTRITIVE VALUE OF AQUATIC PRODUCTS 
Studies on the nutritive value of aquatic products have always 
occupied an important place in the Bureau’s technological investiga- 
tions because the nutritive value of a finished product ready for mar- 
keting is in most instances the true yardstick or measure of the value of 
a new method of processing or an improvement in existing methods in 
the industry. For example—assuming that costs of processing are 
equal in each case—if a new method of manufacturing fish meal or 
a new method of freezing fish fillets produces a finished product of 
better quality, measured in terms of food value, then that is a true 
estimate of its worth, or justification for its commercial application. 
The problems undertaken in this field during the past year have 
been concentrated on determination of the nutritive value of the edible 
portion of fishery products, more particularly the biological value of 
the protein. Considerable effort has also been expended on evaluation 
of the feeding value of fish meals and a study of changes resulting 
from conditions of processing and storage. 
Study also was made of the biological value of the protein of salmon 
taken under different physjological periods, such as prior to migration, 
during migration, and during spawning. Acute and chronic toxicity 
tests with certain kelp products, Irish moss, and agar, have also been 
carried out by an industrial fellowship. 
NUTRITIVE VALUE OF PROTEINS OF CERTAIN SHELLFISH 
Studies were conducted to determine the nutritive value of the pro- 
tein from. the edible portion of various species of shellfish. Adult rats 
were fed known amounts of the various proteins and the quantity 
used for maintenance was determined in metabolism trials. All of 
the proteins were well digested. 
On the basis of 100 representing complete utilization for mainte- 
nance, the protein of beef round (control) scored 70; of white meat 
from. blue crab, 74; of shrimp, 77; and for the Hastern oyster the 
comparative score was 90. These data corroborate the previously 
reported findings that the proteins from fishery products are superior 
to beef round in promoting growth. 
NUTRITIVE VALUE OF ALGINATES FROM KELP 
An industrial fellowship was sponsored by the Kelco Corporation, 
San Diego, Calif., to conduct certain biochemical and pharmacological 
studies of the nutritive value of products derived from the seaweed 
