14 BULLETIN" 1010, U. S. DEPARTMENT OE AGRICULTURE. 



Table 7. — Comparative bleaching effect of fuller' s-earth treatment and the deodorizing 

 process (200° C.) on corn oil, as indicated by Lovibond color readings in a 2-inch cell. 



Nature and time of treatment. 



Color. 



Yellow. 



Red. 



No treatment 



60.0 

 10.4 

 11.2 



19.2 

 5.0 



4.8 



Deodorization for two hours ....... 



3.2 



Deodorization for four hours 



3.6 



Treatment with fuller's earth 



4.0 



Treatment with fuller's earth and subsequent deodorization for two hours at 200° C . . 



1.3 



From these experiments it is evident that the deodorizing process 

 results in a greater bleaching of the oil than the treatment with fuller's 

 earth alone, but the finished oil is by no means as thoroughly bleached 

 as when both treatments are employed. 



COMPARATIVE REFINING QUALITIES OF CORN OIL FROM DRY AND 

 WET PROCESS GERMS. 



The manufacture of corn products falls into two general classes. 

 In the manufacture of meal, flour, and hominy products it is 

 necessary that the corn be degerminated in the dry condition; in 

 the manufacture of the various starches and glucose products 

 the corn is first thoroughly soaked before being degerminated. 8 This 

 difference in the degerminating methods gives rise to two types 

 of oil. The oil produced from the wet-process germs has a tendency 

 to contain a somewhat higher percentage of free fatty acids. In other 

 respects the two types are fairly similar. 



To determine the relative quality of the edible oil obtainable from 

 each of these two types of oil a sample of each was neutralized, 

 bleached, and deodorized by the methods described. Sample A con- 

 sisted of a composite mixture of oils from five large hominy mills, and 

 sample B was a composite of oils from five starch and glucose plants. 

 Of these crude samples oil A contained 0.92 per cent of free acids and 

 oil B contained 2.17 per cent. Oil B was slightly darker than oil A. 

 Both oils gave positive reactions to the Kreis reagent for aldehydes 

 in dilutions of 1 to 20. 



The oils were treated with caustic soda according to method 2, thus 

 reducing the percentage content of acids to 0.019 in oil A and 0.023 

 per cent in oil B. A slight bleaching resulted from this treatment. 

 The Kreis reagent showed a weak reaction for aldehydes in both oils at 

 dilutions of 1 to 10. Both oils were then bleached with 6 per cent of 

 fuller's earth, according to the method described. The treatment re- 

 duced the color in A to 10 yellow and 1.0 red and in B to 19.2 yellow 

 and 3.0 red (2-inch cell) . 



• Sievers, A. F. The production and utilisation of corn oil in the United States. TJ. S. Dept. Agr. Bui. 

 904, 23 p. 11 figs. 1920. 



