22 



BULLETIN 904, U. S. DEPARTMENT OF AGRICULTURE. 



ML 



tank. (Fig. 11.) The treatment received in this tank is of great 

 importance. Essentially this treatment consists of heating the 

 oil to about 400° F. under vacuum by means of steam jackets 

 and steam coils, superheated steam being used in these coils. Through 



a secondary coil with perforations, super- 

 heated steam is passed into the oil. This 

 treatment is continued for several hours, 

 after which the steam is turned off and 

 the oil allowed to cool under reduced 

 pressure to normal temperature. The 

 oil is thus further bleached, the peculiar 

 odor and taste are removed, and a bland, 

 tasteless, and odorless oil is produced 

 which varies from a pale yellow to a 

 very light straw color, according to the 

 efficiency of the treatment. 



The process of deodorizing constitutes 

 the most difficultpart of the several proc- 

 esses required to produce edible corn 

 oil, and the details of the operation vary 

 considerably in the several refining 

 plants. Questions of temperature and 

 time of treatment are determined largely 

 by experimentation and the experience 

 of the men in charge. The character of 

 the crude oil used is also in some cases 

 a determining factor. 



After the oil is cooled in the deodorizer 

 it flows or is pumped into the storage 

 tanks. While in storage it is in some 

 cases kept at a low temperature in order 

 to effect the separation of stearin, which, 

 structed with jacketed bottoms for however, does not separate from corn oil 



steam heating. to ^ game extent ag f rom gQme other 



vegetable oils. Finally, the oil is filtered through coarse paper or 

 cloth to clarify and brighten it, especially when intended for the 

 retail trade. 



THE FUTURE OF CORN OIL. 



So far as can be concluded from the survey of the industry, corn 

 oil appears to have established itself as a satisfactory product for 

 which there will be a steady demand in the trade. That the oil can 

 always be produced is assured by virtue of the fact that it is a by- 

 product of the manufacture of certain staple corn products, and it is 

 only in case of an overproduction of fats and oils that it might be 

 discontinued and the germs disposed of as feed. Such a situation 



Fig. 11. — Type of tank used for deodoriz- 

 ing corn oil. These tanks are also con- 



