BULLETIN 630, U. S. DEPAETMEXT OF AGBICULTTJKE. 





not be purchased in any considerable quantities and are little used 

 in this country as such, very considerable quantities are consumed 

 annually as a constitutent of the nuts in which they occur. 



Inasmuch as sufficient quantities of these nut oils could not be 

 procured in the open market, a supply of good grade nuts of the 

 varieties to be studied was procured and the oils were expressed under 

 laboratory conditions with a hydraulic press having a capacity of 

 35 tons pressure on a 6-inch plunger. All of the oils were " cold 

 pressed " and were of excellent quality, being in such good condition 

 that no refining was necessary. They were allowed to stand some hours 

 in order that any suspended matter might settle and then they were fil- 

 tered through one thickness of ordinary filter paper. In all instances 

 the oils were of good color, without odor, and possessed a bland 

 flavor ; in one or two instances more or less of the characteristic flavor 

 of the nuts from which the oils were derived could be detected. Since 

 they were used within a short time after they were expressed, little 

 information was obtained in regard to the keeping quality of the oils. 



The press cake remaining after the oils had been expressed from 

 the nuts was quite palatable though not as " rich " as the nuts, and 

 rather dry if eaten alone. The characteristic flavor of the nuts was 

 retained by it and was in many cases intensified. Since the press 

 cake was derived from a good grade of cleaned nuts it had consider- 

 able interest as a possible food material, especially in view of its 

 high protein content. That obtained from several varieties of nuts 

 was accordingly studied in this office from a dietetic standpoint, and 

 various recipes for its use were developed. The value and possible 

 uses of such press cake will be discussed in a later publication. 



In the studies of the digestibility of the 16 animal or vegetable 

 fats, reported in previous bulletins, an average of eight tests was 

 made with each fat; in only one case were there less than five 

 experiments. Because of the limited available supply of the oils 

 considered in this paper only three or four tests could be made with 

 the oils studied. 



METHODS OF PROCEDURE. 



The digestion experiments with the nut oils were conducted by the 

 same methods as those with the animal and vegetable fats already 

 reported, the object being to maintain identical experimental condi- 

 tions for each fat studied and thus to make the values obtained for 

 the digestibility of the different fats directly comparable with one 

 another. 



As in the earlier experiments, a blancmange, or cornstarch pud] 

 tfing, served as the medium for introducing the fat under considera- 

 tion. The blancmange was prepared by the method outlined in a. 



