Page:Principles preservation fish by salt.djvu/15

and they even change in the same individual fish as staleness develops. Now, most of these odoriferous substances are soluble in water or brine, and after the salting process would be found in the brine. They are not replaced when the fish is soaked out. It might therefore be anticipated, as has actually been found, that the fresh fish, disagreeable because of the presence of strong substances, are rendered sweet by the removal thereof in the salting process.

If this lead were followed in detail, it is quite possible that salting would turn out to be the best method of utilizing fishes that are of a rather poor edible quality when in the fresh condition. This aspect of the matter deserves particular attention of the canners. Many species of fish of great abundance might in time be profitably packed if the flavor were inviting. With highly improved technique in salting, the undesirable flavors might be removed by curing and soaking out before canning. This process would be unthinkable on the basis of the customary salting methods where there is in the end an excessive saltiness or flatness of flavor, but the mild, sweet fish prepared by improved technique and pure salt is a much more promising possibility for canning.

DRY SALTING AND BRINE SALTING COMPARED.

The next question taken up in the investigations referred to was that of the relative merits of the application of the salt to fish in the dry state and as a concentrated brine. In the Chesapeake Bay region the herring are usually pickled in brine. By a strict comparison of the two methods it was found that there is developed a smaller quantity of the products of decomposition–the amino acids–when the salt is applied dry. Not only this, but it was also found that salt applied in the dry condition penetrates the fish more rapidly.

Among the products of protein decomposition are amino acids. A determination of amino acid nitrogen was taken as a measure of decomposition–the more of the amino acid nitrogen present the greater the amount of decomposition. This being true, the following table, summarized from Tressler's results, will show the superiority of dry salt over strong brine for preserving fish.

Amounts of Amino Acid Nitrogen Formed Per Kilogram of Fish at Different Temperatures.

Method of salting.	Tem- pera- ture.	Amount of amino acid nitrogen per kilogram of fish after–					Condition at end of salting period.
		19 hours.	67 hours.	5 days.	7 days.	9 days.
	° F.	Grams.	Grams.	Grams.	Grams.	Grams.
Dry salted	63.0	0.078	0.083	0.085	0.085	0.119	Good.
Brine salted	63.0	.089	.129	.135	.183	.234	Do.
Dry salted	70.0	.084	.086	.098	.097	.126	Do.
Brine salted	70.0	.100	.165	.158	.190	.292	Do.
Dry salted	75.5	.077	.092	.099	.104	.134	Fair.
Brine salted	75.5	.102	.186	.179	.228	.316	Do.
Dry salted	80.0	.074	.086	.119	.141	.158	Do.
Brine salted	80.0	.086	.189	.210	.300	.383	Spoiled.
Dry salted	87.0	.076	.089	.159	.195	.208	Do.
Brine salted	87.0	.097	.244	.266	.377	.510	Do.
Dry salted	93.0	.065	.105	.151	.193	.236	Do.
Brine salted	93.0	.080	.238	.320	.465	.666	Do.