12 BULLETIN 1475, U. S. DEPARTMENT OF AGRICULTURE 
three or four large bunches of fruit. Some trees yield a ton of fruit, 
which contains about 270 pounds of kernels. Like the cohune. the 
nuts have extremely thick and hard shells. It is said that the dried 
kernels contain from 65 to 68 per cent of oil, which is expressed in 
the same way as coconut oil (p. 9). The oil, being similar to coco- 
nut oil, is used for the same purposes. 
7 
CORN OIL 
Corn oil is obtained from the small germ portion of the common 
Indian corn or maize. The United States is the largest producer 
of corn oil, but Canada, Argentina, and South Africa are producing 
it in increasingly large quantities. 
The germ of corn is about half oil, but on the basis of the whole 
kernel the oil content is only from 3 to 6.5 per cent. Were it not 
for the fact that in the preparation of hominy, cornstarch, and other 
corn products the germ is almost completely separated from the 
rest of the kernel, corn oil doubtless would be a mere curiosity in- 
stead of an important commercial product. Corn may be degermi- 
nated by the dry process, or by the wet process. 
The wet process, employed in starch and glucose plants, is as 
follows: The cleaned corn is steeped from 30 to 40 hours in water 
containing about 0.2 per cent of sulphurous acid, removed from the 
water, and passed through an attrition mill of a special type. The 
shredded corn is mixed with a large quantity of water in floating 
vats, and the mixture is slowly agitated in such a manner as to 
cause most of the germs to float and pass over the lower end of the 
vat. The germs, together with much starchy water, are passed 
through reels with perforated sides and washed to remove the ad- 
hering starch. The washed germs are passed through moisture ex- 
pellers and then through steam-heated rotary driers, which reduce 
the moisture content to about 5 per cent. The dried germs are passed 
through a set of flaking rolls, which break the oil cells but do not 
grind the material into flour. The general practice is to extract the 
oil with expellers, although hydraulic presses can be used. 
The dry process is as follows: The cleaned corn is agitated in a 
suitable container and then treated with sprays of water or steam 
until it has a moisture content of about 20 per cent, after which 
it is passed through the degerminating machine. The germ thus 
separated contains some bran and meal, the quantity depending on 
the care practiced in operating the machine. The germ material is 
dried and passed through hominy reels, which remove more of the 
bran and meal. Then the germs are passed through the flaking 
rolls and the oil is expressed with expellers. 
As the dry-process germs are mixed with meal, the yield of oil 
is only about 0.5 pound per bushel of corn. By the wet process it 
is about 1.5 pounds. As would be expected, however, the oil obtained 
from the dry-process germs is of much better quality than that from 
germs obtained by the wet process. 
Most of the corn oil is now refined in a manner somewhat similar 
to that employed for cottonseed oil (p. 6). 
Corn oil is used for edible purposes, in the manufacture of some 
soaps, and, along with linseed oil, in paste paints to prevent harden- 
ing in the containers. 
