534 "U. S. BUREAU OF FISHERIES 



more care would be uecessaiy for the storage of fats from fish and 

 marine animals. 



In using fish fats for culinary purposes attention should be given 

 to the possible necessity for modifying somewhat the procedure 

 inA^olved in the culinary use of common fats such as lard and butter. 

 Studies with regard to the scorching temperature of common culinary 

 fats siiow that in frying (particularly deep frying) there is a delinite 

 tempej'ature for each fat at which food is most satisfactorily cooked 

 and with the absorption of a minimum of fat. In a previous publica- 

 tion ^ it was noted that this temperature is about 260° F. for beef 

 fat, 350° F. for lard, and 390° F. for cottonseed, coconut, and peanut 

 oils. It was noted further that if these temperatures were lowered 

 20° for the animal fats and 40° for the vegetable fats the amount of 

 fat absorbed by the cooked foods increased 25 per cent. Accordingly, 

 when using fish fats for culinary purposes one should be prepared to 

 nbodify ciuinary practices in accordance wdth the nature of the 

 particular fat under consideration. 



DIGESTIBILITY 



Hundreds of digestion experiments with human subjects have been 

 conducted to determine the extent to which the edible fats from land 

 plants and animals are utilized by the human body. These show that 

 the liquid fats as a class are more completely utilized by the body 

 than are the solid fats. While in some instances there is little differ- 

 ence between the digestibility of solid fats with a relatively high 

 melting point and that of the liquid fats, there may be a difference of 

 10 or 12 per cent between the digestibility of the more completely 

 digested liquid fats and that of the less completely digested solid fats. 



Applying this generalization concerning the digestibility of fats 

 obtained from land plants and animals to the digestibility of fatty 

 substances obtainable from fish, one would conclude that the digest- 

 ibility of edible fish fats would be quite similar to that of vegetable 

 fats. 



As regards actual data concerning the digestibility of lish fats, one 

 finds very little information recorded. The digestibility of fish fats 

 has been studied to a limited extent by a niunber of investigators, 

 who conducted digestion experiments with human subjects. Milner 

 (1905) studied the digestibility of fat contained in canned salmon 

 and in fresh cod steaks when they were eaten as constituents of a 

 simple mixed diet. He found that the fat of both the salmon and 

 cod was 97 per cent digested. Oshima (1905) reports the digestibility 

 of the fat contained in the edible portion of fresh fish to be as follows: 

 Porgy, 73 per cent; salmon, 94 per cent; poulpe, 60 per cent; shell- 

 fish {Tapes Philippinarum) , 85 per cent; and dried herring, 80 

 per cent. 



The results of digestion experiments conducted by the writer - 

 while employed at the United States Department of Agriculture 

 show that fish fats are well utilized by the human body. In studies 

 with fresh mackerel and butterfish and canned salmon and dogfish 

 the digestibility of the fat was found to be 95 per cent for Boston 



1 Holmes, A. 1)., and H. L. Lang: Fats and their economical use in the home. United States Depart- 

 ment of Agriculture Bulletin No. 469, Dec. 15, 1916, 26 pp. 2 flgs. Washington. (See p. 19.) 



'■' Holmes, A. D.: Experiments on the digestibility of fish. United State.? Department of Agriculture 

 Bulletin No. 649, Apr. 13, 1918, 14 pp. Wtishington. (See p. 14.J 



