202 U. S. BUREAU OF FISHERIES 
as described in previous annual reports of this Division and, during 
1938, a report was given at the September meeting of the American 
Chemical Society in Milwaukee, Wis. This report deals specifically 
with the use of a water extract of the active principle of oat flour as the 
antioxidant. Boston mackerel were treated with this extract and 
then frozen by the usual commercial method. As a means of compari- 
son, control samples of Boston mackerel were given the usual commer- 
cial handling without the application of the extract of antioxidant 
and were frozen. Periodic examinations of these samples over a 
period of 6 months indicated that those fish treated with the oat flour 
extract were of definitely superior quality to the untreated samples. 
These results are very interesting because earlier studies of the 
direct application of oat flour, or solvent extracts prepared from oat 
flour, gave only a very mild protective action, not sufficiently pro- _ 
nounced to attract the interest of the fishery industries for commer- 
cial application. Moreover, the direct application of oat flour de- 
tracted from the appearance of the resultant product and the solvent 
extracts were of limited application because of their oily nature. How- 
ever, tests conducted in the College Park and Seattle laboratories thus 
far of the water-soluble extracts of oat flour and concentrates pre- 
pared therefrom did not affect the appearance of the fish so treated 
and, as indicated above, were much more effective in retarding ran- 
cidity. Therefore, these water-soluble extracts of oat flour are being 
tested on fresh salmon prior to canning, mild-cure salmon, kippered 
salmon, frozen salmon, and frozen halibut. In the case of the mild- 
cure and kippered salmon, the extracts were used in conjunction with 
the normal brining processes while in the frozen products the extracts 
are being used in connection with washes prior to freezing and in the 
glazing bath. Since these latter tests are now being run under com- 
mercial storage conditions, sufficient time has not elapsed to permit 
definite conclusions. So far, only moderate improvement has resulted. 
Such results must be attributed more to the extreme difficulty of re- 
tarding rancidity in fish oils than to the lack of effectiveness of the 
cereal flour products as antioxidants. 
STUDIES OF LACTIC ACID AS A POSSIBLE INDEX OF DECOMPOSITION IN 
FROZEN FISH 
Progress on this project was interrupted during 1938 because of the ~ 
resignation of the investigator assigned to the problem. Another 
chemist has recently been assigned to the work. 
It is known that lactic acid rises to a maximum content in fish 
muscle during the rigor of death, and the importance of muscular 
rigor, in its relation to the onset of spoilage in sea fish, has been 
emphasized by other investigators in this field. It has also been 
shown that the alkaline reaction of fish muscle and the accompanying 
onset of spoilage of the fish follows after the loss of muscular rigor. 
Thus it is evident that, since spoilage occurs after the lactic acid 
content of the fish muscle reaches a maximum, the determination of 
lactic acid in fish flesh before and during a period of cold storage is of 
value ‘in obtaining direct knowledge of the processes of decomposition 
of fish. 
Recently, sea trout have been obtained by our technologists from 
Chesapeake Bay and have been frozen under varying conditions of — 
