12 BULLETIN 469, U. S. DEPARTMENT OF AGRICULTURE. • 



margaric acid, for which it was often mistaken, and so it was given 

 the name " margarin." Later, when soft beef fat, or oleo oil, became 

 an important component of this mixture, it was called oleomargarine 

 or oleo. The name does not at present, however, indicate the compo- 

 sition of the oleomargarine. The principal fats used in its manufac- 

 ture in the United States are oleo oil, neutral lard (that is, a spe- 

 cially rendered lard), and cottonseed and other oils. All these ingre- 

 dients must be pure and prepared with care in order that none of 

 them shall have any marked taste or odor. These are mixed in such 

 proportions as will give the final product a melting point very near 

 that of butter. After being thoroughly mixed the fats are churned 

 with a small quantity of milk and sometimes cream, the proportions 

 of these used depending upon the quality of the product desired. In 

 the preparation of high-grade oleomargarine varying quantities of 

 butter are also added. The resulting product is then washed, salted, 

 and worked as in ordinary butter-making processes. Owing to the 

 ease with which a highty colored oleomargarine might be sold as 

 butter, it is illegal to sell oleomargarine unless it is plainly labeled 

 as such, and the practice of coloring it to imitate butter is discour- 

 aged, by a heavy tax. Oleomargarine is not used as extensively in 

 this country as in Europe, where it serves both for table and culinary 

 purposes. If prepared from pure materials and under sanitary con- 

 ditions, it is a wholesome fat, which, according to European investi- 

 gators, is well assimilated. It has an energy value of about 3,500 

 calories per pound. 



VEGETABLE FATS. 



Vegetable fats are prepared on a commercial scale from oil-bearing 

 seeds and fruits and must ordinarily be freed from disagreeable 

 flavors and odors as well as from dirt, by-products, and harmful con- 

 stituents. In general, the process involves cleaning the seeds or 

 fruits and subjecting them to hydraulic pressure. Cold pressed oils 

 usually receive no further treatment. "When the seeds or oily pulp 

 are hot pressed, however, the raw oil is likely to contain free fatty 

 acids and other organic compounds of a disagreeable nature which 

 make refining necessary. The refining process is adapted to the 

 properties of the oil in question. 



OLIVE OIL. 



Olive oil is obtained by subjecting the ripe olives to pressure. 

 The best grade, known as virgin oil, is obtained from perfect olives 

 of the proper degree of ripeness. Lower grades may be obtained 

 either by crushing and pressing an inferior quality of olives or by 

 a second pressing of the residue from the first pressing of the better 

 grades of fruit. The only refining or purification of the better 



