40 



THE SALTIISTG OF FISH. 



the brinc-salt method is not as efficient in preserving fish as the dry- 

 salt metliod. 



The writer wishes to point out the vahie of the amino-acid con- 

 tent of fish and brine as a criterion in estimating and detecting 

 spoilage. Any two lots of the same fish maj' be compared and their 

 relative freshness determined. This may be used for either fresh 

 or salted fish. If the fish have been salted by the same process, this 

 may be done quite easily by determining amino-acid nitrogen in 

 the brines. 



It also seems probable that the increase in amino-acid content 

 could be used to forecast spoilage of fish during the salting period. 

 A rapid rise in tlie amino-acid content of the brine would warn the 

 Salter that his fish were in clanger of spoiling, and the Salter could 

 remove them to cold storage or use stronger brine. 



RATE or PENETRATION OF SALT. 



In addition to following the formation of amino-acid nitrogen in 

 fish salted by these two ways, the rate of penetration of chlorides 

 into squeteagues was followed. This was accomplished in the same 

 manner as the determination of the rates of penetration of different 

 salts described on page 22. 



METHOD. 



The general procedure in these experiments was as follows: Fish 

 of a uniform size (3.5 cm. thickness) were salted with pure sodium 

 chloride by the two methods described on page 36. These two jars of 

 fish were placed in a constant-temperature compartment and sampled 

 at the end of 1, 4, 7, and 10 days. The temperature of the fish did 

 not vary more than 1.44° from the average of 69.44° F. The samples 

 were dried and ashed and the chlorine determined by titration with a 

 silver-nitrate solution. The results are given in Table 11. 



Table 11. — Penetration of Salt into S<jiteteagite, Expressed in Terms of 

 PER cent of Chlorine in Dry Sample, at 70° F. 



The percentage of salt in both .sections is higher throughout in 

 the case of the dry-salted fish than in tlie brine-salted fish. This 

 shows that the salt penetrated more rapidly in the case of the dry- 

 salt method. More data could be given which verify the results 

 of this experiment. 



This work agrees with the results obtained by the estimation of 

 the rate of amino-acid formation. For, when the salt penetrates 



