10 BULLETIN 867, U. S. DEPARTMENT OF AGRICULTURE. 
sitates in most operations the addition of a so-called binder to pre- 
vent the troublesome squirting of the meats from the presses and 
at the same time prevent the introduction of excessive meal into the 
oil. The disadvantages so greatly outweigh the advantages that this 
practice is not followed to any great extent either here or abroad. 
(See under “Solvent extraction.’?) A decorticating machine” is 
illustrated in figure 1. 
HEATING. 
After cleaning, the beans are conducted to the heaters. In 
contradistinction to other vegetable oleaginous materials, castor 
beans can not be 
eround and tempered 
as can flaxseed, pea- 
nuts, soy beans, cot- 
tonseed, and copra. 
The nonfibrous 
nel with its attend- 
ant high oil content 
sogumsup the equip- 
ment that further 
erinding is difficult. 
In addition to these 
technical difficulties, 
the bean contains a 
very active lipase or 
fat-splitting (sapon- 
ifying) enzym, which 
very quickly sets free 
an excessive amount 
of fatty acid. Ac- 
cordingly, every 
effort is made to 
deliver the beans 
to the presses as whole as possible. The reason they are heated 
at all is to render more mobile the naturally heavy viscous 
Fic. 1.—A castor-bean decorticator. 
oil. Probably even this would not be done if such treatment served © 
materially to impair the quality of the oil. The temperature to which 
the beans are raised varies from 100° to 120° F. 
To test the effect of heating undamaged beans, a sample from Santo 
Domingo was heated for 24 hours at 70° C. (158° F.). It was then 
carefully picked over to eliminate any black beans, and cold pressed 
without any further heating in a laboratory cage press at 1,500 pounds 
apphed pressure per square inch. A sample of unheated beans wa 
pressed as a control. In each case the first runnings were discarded 
character of the ker- 
5 
