16 



BULLETIN 904, U. S. DEPARTMENT OF AGRICULTURE. 



1 and 2 per cent of free acids, the oil from the 1917 crop averaged 

 nearly 10 per cent and in many instances was as high as 15 to 17 

 per cent. It was also darker than usual and the expelling was more 

 difficult, in some cases more than 15 per cent of the oil being left in 

 the cake. Naturally the refining of this oil involved big losses, and 

 consequently it brought a greatly reduced price in the crude state. 



COMPARISON OF THE OIL-PRODUCTION OPERATION IN DIFFERENT 



MILLS. 



In order to ascertain the extent to which the products from the 

 various mills differed, determinations were made of the fat and mois- 

 ture content of the germ, oil cake, and feed secured from these mills, 

 and samples of the oils they produced were tested for free fatty 

 acids. Table I shows the results. 



Table I. — Comparison of the fat, moisture, and free fatty acid content of material -produced 

 in representative corn-products mills in the United States, showing the results of the 

 wet and dry processes of degerminating the kernels. 







Source of material, different mi 



Is (per cent). 





Material analyzed. 



1 



2 



3 



4 



5 



6 



7 



Average 



of 7 

 mills. 



Sec. A. — Hominy mills (dry 

 process): 

 Free fatty acids — 



1.29 

 .10 



0.78 



0.73 



0.S8 



2.34 



1.27 



0.88 



1.11 







Fat- 



13.3 

 5. SO 

 6.36 



2.92 

 3.37 

 10.35 



&9.17 



14.37 

 4.19 

 6.15 



8.66 

 10.55 

 12.66 



1.39 

 .17 



41.99 

 7.35 

 3.63 



4.68 

 7.89 

 10.38 



15.68 

 5.23 

 7.90 



22.41 

 7.90 



16.66 



9.38 



24.90 

 a 12.97 



17.88 







6.82 



Feed 



5.93 



5.92 



Moisture — 



S.49 

 7.96 

 10.36 



5.34 

 .11 



50.14 



a 6. 04 



2.85 



4.62 

 7.15 

 11.22 



9.61 

 4.45 



4.31 

 2.74 



6.96 







5.81 



Feed 



12.50 



1.78 



10.86 

 1.65 



11.35 



Sec. B. — Starch and glucose 

 plants (wet process): 

 Free fatty acids — 



Crude oil 



2.14 

 .10 



55.96 



8.35 

 3.36 



2. 28 



2.05 



2.39 



Fat- 

 Germs 



51.85 

 8.90 



c 23. 78 

 8.08 

 6.S5 



5.46 

 9.20 

 9.53 



22.35 

 9.25 

 5.20 



4.38 

 3. SO 

 8.91 



49.20 

 10.30 



42.23 

 8.70 



Feed 



4.38 



Moisture — 



3.75 

 9.74 

 11.12 



5.44 

 S.67 



4.37 





7.74 



Feed 



9.76 



10.15 









a Not included in average, b Immature corn of 1917, not included in average, c Immature corn of 1917. 



A study of Table I shows that there is a wide variation in the 

 character of the material produced in the various mills. While the 

 percentage of free fatty acids in the oils is low it is evident that the 

 oil obtained from germs separated by the dry process of degerminating 

 is somewhat lower than that from the wet process. This might be 

 expected from the nature of the two processes. So far as observation 

 indicates, however, the refined oil from the two processes shows no 

 noticeable difference. The percentages of fat in the germs and oil 



