SEED OILS 109 



which arachis oil (peanut or ground-nut oil) is obtained by ex- 

 pression. High-grade arachis oil is nearly colorless and has a 

 pleasant taste. It is edible and is used as a salad oil, especially 

 as a cheaper substitute for olive oil. The lower grades are used 

 for making soaps or for burning. 



Very little peanut oil is produced in the Philippine Islands, 

 but its manufacture on a large scale is well worth consideration, 

 as in certain other countries it is an article of considerable com- 

 mercial importance. 



According to Thorpe,* the total quantity of arachis nuts pro- 

 duced in the world is approximately 350,000 tons per year. 

 Large quantities of these nuts are used in France, Austria, 

 Germany, and the United States. Although about 50,000 tons 

 of peanuts are grown yearly in the United States, the demand 

 is greater than the supply and consequently large quantities of 

 nuts are imported. 



Concerning the manufacture of peanut oil, Lewkowitsch j 

 states that the nuts are shelled by special machinery. The ker- 

 nels, which contain 43 to 45 per cent of oil, are ground and the 

 oil expressed from the ground material by hydraulic pressure, 

 two and sometimes three times. The first expression is carried 

 out at the ordinary temperature, the second at about 31° C, 

 and the third at about 52° C. 



The cake serves as an excellent cattle food, as it contains 

 the highest amount of proteins of all known oil cakes ; moreover, 

 these proteins are more easily digested than those of other cakes. 



Thorpe * states that the average composition of the nuts ob- 

 tained from various places is as follows: 



Per cent. 



Arachis oil 38 to 50 



Water 4.6 to 12.8 



Albuminoids 26 to 31 



Carbohydrates 5 to 19 



Fibre 1.1 to 4.1 



Ash 1.6 to 3.0 



Mitchell t gives the following constants for peanut oil : 



Specific gi-avity - 0.917 to 0.9256 



Reichert-Meissl value 0.48 



Hehner value 95.5 



Iodine value 92 to 100.8 



The principal fats w^hich peanut oil contains are olein, linolin, 

 palmitin, stearin, arachidin, and lignocerin. 



* Thorpe, E., Dictionary of applied chemistry. Volume 1, page 286. 

 t Lewkowitsch, J., Oils, fats, and waxes. Volume 2, page 304. 

 t Mitchell, C. A., Edible oils and fats. Page 58. 



