8 BULLETIN 469, U. S. DEPARTMENT OF AGRICULTURE. 



on the farm. Beef and mutton fats, or tallows, as they were gen- 

 erally known, were used in cooking to some extent in the form 

 of "dripping" obtained from cooking meats, but found a much 

 wider use for candle and soap making. Chicken fat was also used 

 in a limited way. As the population began to concentrate in cities 

 and towns, the introduction of central slaughterhouses and rendering 

 plants made it possible to obtain both meat and fat separately in such 

 ways as met individual requirements, and home rendering of fats 

 quite generally disappeared except in rural regions. The increasing 

 population created a demand which soon exceeded the available sup- 

 ply obtained from slaughtered animals, and this made it necessary 

 to seek additional sources of edible fats. Naturally, olive oil, used 

 for food purposes in some parts of Europe and the Orient and less 

 generally in the United States, suggested the possibility of the utili- 

 zation of other vegetable fats, and as the methods of refining were 

 improved cottonseed oil came to be very commonly used, and, to a 

 less extent, coconut, peanut, and corn oils. At the present time there 

 are also a number of vegetable fats on the market, some of which 

 are simply refined and used alone or in admixture, while others have 

 been treated by special processes designed to render them harder or 

 otherwise changed in character. In the following pages general 

 information is given regarding the nature, source, and use of some of 

 the more important edible fats. 



ANIMAL FATS. 



BUTTER. 



Butter is the most popular and widely used of all fats in the 

 United States, it being estimated that from 17 to 18 pounds per 

 capita are consumed yearly, most of it for table purposes. Its food 

 value is due largely to the energy it furnishes, which is about 3,500 

 calories per pound. It consists of the fat of milk, some water, and 

 a little curd and added salt. Butter is of two kinds, salted 

 and unsalted. Commercial butter contains*approximately 82.5 per 

 cent of fat, which consists chiefly of palmitin and olein with small 

 amounts of myristin, butyrin,' and other glycerids of the fatty acids. 

 The color varies considerably with the nature of the food materials 

 eaten by the cow ; the yellow is deeper in summer when green food 

 is eaten. It is a common practice to add vegetable coloring matter, 

 especially during the winter months, to intensify the natural color. 

 Since butter tends to deteriorate easily, care in its manufacture is 

 necessary to secure a wholesome product with good keeping qualities. 

 The milk from which the cream is separated should be free from 

 disease-causing bacteria as well as from microorganisms which would 

 produce undesirable flavors or odors in the butter. For this reason 



