THE PRODUCTION OF CORN OIL. 15 



EFFECT OF COLOR AND CONDITION OF THE CORN ON THE YIELD AND 

 CHARACTER OF THE OIL. 



Both white and yellow dent corn are used in this country for the 

 manufacture of corn products, but the white seems to be generally 

 preferred. In hominy mills the variety used is determined largely 

 by the kind of corn meal demanded. Certain sections of the country 

 consume only yellow corn, products, while others prefer the white. 

 Starch and glucose makers use both kinds, most operators claiming 

 that the products are the same. There is no indication that there 

 is any difference in the oil from the two kinds, but it is the opinion 

 of some that the white corn has a larger germ and hence produces 

 more oil to the bushel. This opinion is based largely on conjecture. 



The opinion seems to be quite general, especially among the dry- 

 corn millers, that the quantity of oil obtainable decreases somewhat 

 with the age of the corn. Their theory is that the oil "creeps" out 

 of the germ into the starchy portion of the kernel and is thus lost 

 in the hominy products and feed. No definite study of this question 

 seems to have been made. It is possible, however, that with age and 

 the drying of the kernel the germ becomes more brittle and thus 

 chips and breaks more in the degerminators, the smaller fragments 

 being lost in the feed. The monthly oil records for a number of 

 years of one starch and glucose plant were carefully examined, and 

 it was found that the quantity of oil in the corn, calculated on a 

 moisture-free basis, was about 4.3 per cent, as determined by ex- 

 traction with carbon tetrachlorid. The corn milled during the sum- 

 mer months was somewhat higher in oil content. While the increase 

 was only about 0.3 per cent, it was shown by the records that this 

 increase occurred every year. As a rule, the corn used in the summer 

 months is the last of the previous year's crop. It would seem, 

 therefore, that if the general assumption is true that the older corn 

 yields less oil, it is not because there is less oil in the kernel, but 

 because the degerminating is less efficiently performed on the older 

 corn. In the dry process of degerminating, this is very likely to 

 be the case. 



The condition of the corn with regard to its maturity has a pro- 

 nounced effect upon the character of the oil and the quantity ob- 

 tainable. According to figures available at one of the glucose plants, 

 the soft corn of 1917 had a somewhat higher oil content than well- 

 matured corn, but the general experience with that year's crop 

 showed a decidedly reduced yield. The explanation usually ad- 

 vanced is that some of the oil was distributed in the kernel outside 

 of the germ and was lost. A most interesting feature of this oil was 

 its high acid content. While normally the oil averages between 



