MAINE SARDINE INDUSTRY. 



71 



Table 30 gives the results of the determinations of ammoniacal 

 nitrogen in sardines stored for various periods of time. 



Table 30. — Ammoniacal nitrogen content of sardines stored for various periods. 



Condition offish. 



Period held. 



Ammoniacal ni- 

 trogen per 100 

 grams. 



Nessler. 



Titra- 

 tion. 







Mg. 

 107.8 

 121.7 



Mg. 



147.6 

 189.6 



203.1 

 206.1 

 204.5 

 271.8 

 239.4 

 223.0 



Do 



24 hours 



In pickle: 





do 







do 













do 







....do 











From the nature of the material, coupled with the well-known fact 

 that amines are formed in the decomposition of fish, fish brine being 

 a source of trimethylamine, amines were naturally looked upon as 

 responsible for the discrepancy between the values obtained by the 

 two methods of analysis, and possibly were partly responsible for the 

 increase in the ammoniacal nitrogen which occurs on standing. 

 Evidently a change occurs in canned sardines on standing, sub- 

 stances having an alkaline reaction (amines) , determined as ammonia 

 by the titration method, being liberated. Unfortunately, the Nessler 

 method for determining ammonia is not reliable in the presence of 

 amines. The difference in the values obtained by the methods em- 

 ployed for ammonia, while giving some indication of the amount of 

 amines present, is not even sufficiently accurate to warrant regarding 

 it as an approximate measure of the amine content. 



The interesting fact that older packs of sardines contain larger 

 amounts of ammoniacal material than those which have stood for 

 only a short time was definitely proved by analyzing samples of 

 commercially packed sardines which had stood for 2, 4, and 6 

 years in a cellar where the temperature was practically uniform 

 and never reached the freezing point. In these analyses determina- 

 tion of the total volatile nitrogen and " ammonia " by the Nessler 

 method, as well as the separation of ammonia and amines in the total 

 volatile material, were made. 



On opening the cans the two brands which had been packed for 2 

 years were found to be in very good condition. The fish were 

 slightly colored by what appeared to be iron from the lid of the 

 can, which was badly detinned. The cans in the 4-year-old lot 

 looked worse than any of the other samples. A large amount of a 

 white, soft material, probably stearin from the oil, was spread over 



