40 



THE SALTITTG OF FISH. 



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

 salt method. 



The writer wishes to point out the value 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 may be compared and their 

 relative freshness determined. This inny 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 the amino-acid content of tlie brine would warn the 

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

 remove them to cold storage or use stronger brine. 



RATE OF 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. 



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 Sai-t into Squeteague, Expressed in Te^ims of 

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



The percentage of salt in both sections is higher throughout in 

 the case of the diy-salted fish than in the 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 woik agrees with the results obtained by the estimation of 

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



