THE PREPARATION OF CORN OIL. 
11 
oil with practically no unpleasant odor or taste. The details of the 
process differ somewhat, according to the kind of oil that is being 
treated. In the case of corn oil the object of the deodorizing process is 
to remove the peculiar cereal flavor which is so characteristic of the oil. 
The experiments performed in the deodorization of corn oil were 
conducted with a view of determining the proper temperature to be 
maintained and the time of treatment necessary to give the oil the 
best flavor and at the same time the lightest color. Some preliminary 
experiments consisted in blowing the previously neutralized and 
bleached oil with steam under atmospheric pressure. After four or 
five hours of such treatment the oil when separated from the con- 
densed steam was found to be entirely odorless, but the color was 
not improved to any great extent. The oil thus treated was then 
divided into three lots, two of which were dehydrated and the other 
kept as a check. Table 5 gives the condition of the three oils after 
standing in well-filled bottles for some time. 
Table 5. — Effect of the presence of moisture on the keeping quality of deodorized corn oil. 
Sample. 
Treatment for removing 
moisture. 
Quality of oil after- 
One week. 
Four weeks. 
Twelve weeks. 
No.l 
None 
Slightly rancid 
Good quality 
do 
Distinctly rancid 
and somewhat 
musty odor. 
Good quality 
do.. 
Very rancid and 
musty. 
Rancidity becom- 
ing noticeable. 
Good quality. 
No. 2..... 
No. 3 
Heated under vacuum to 95° C 
for one hour. 
Stream of carbon dioxid passed 
through the oil for seven hours 
at 70° C. 
It is evident that although steam at ordinary pressure volatilizes 
the odorous constituents of the corn oil and produces a very accept- 
able product as regards taste and odor, the oil must subsequently 
be dehydrated in order to prevent it from rapidly becoming rancid. 
With very few exceptions vegetable oils are deodorized in com- 
mercial practice by blowing steam through the oil at a temperature 
of about 200° to 250° C. (392° to 437° F.) under high vacuum for 
about an hour, the time depending to some extent upon the character 
of the oil and the type of equipment. The object is to obtain an oil 
of satisfactory color and taste in the shortest time possible. 
The oil is heated to 200° C. in the deodorizing tank either by direct 
heat or by means of superheated steam in closed coils placed in the 
bottom of the tank. Steam is then blown through the oil from a 
perforated coil. The practice differs with respect to this process, in 
some cases the steam being superheated. It is evident, however, 
that the use of superheated steam for this purpose will aid in keeping 
