210 VITAMIN D GROUP 



III. Industrial Preparation 



CHARLES E. BILLS 



The patent index in Rosenberg's^ book bears witness to the effort and 

 ingenuity which have been appHed to the industrial development of vitamin 

 D. The index includes 242 titles and short abstracts of the more important 

 United States and foreign patents through 1941. 



The preparation of fish oils is described in Tressler and Lemon's^ "Marine 

 Products of Commerce" and especially in Brocklesby's' "Chemistry and 

 Technology of Marine Animal Oils." The ancient method of rendering fish 

 liver oils by the natural disintegration of livers began to be replaced by 

 steam cooking about the middle of the nineteenth century .•* With technical 

 improvements, steaming sufficed for most vitamin oil production until 

 about 1933, when interest developed in the production of high-potency oils 

 from low -yield livers. 



Nearly all high-potency fish liver oils are manufactured by a process 

 based on the liquefaction of the liver with alkali. This process was worked 

 out independently and at about the same time by Young and Robinson^ 

 and Wallenmeyer.^ Sufficient alkali is added to the livers so that, with 

 heating, they go into solution, but the amount of alkali is limited so that 

 substantial saponification of the oil does not occur. The oil is then separated 

 centrifugally from the aqueous liquor, washed, and refined as desired. The 

 vitamin D in liver oils is remarkably stable, but in consideration of the 

 less stable vitamin A, the oils are usually stored under inert gas or in tanks 

 with floating tops. 



The patent literature contains many references to equipment designed 

 for the antiricketic activation of foods under the basic Steenbock'^ patent. 

 The common aim in these inventions is the brief exposure of a shallow, 

 moving layer to the rays of a mercury or carbon arc. Milk, because of its 

 suitability for treatment, and its importance to infants and children, has 

 been most extensively activated. A representative apparatus for irradiating 

 milk is shown in Fig. 14. Direct activation of milk is practiced less now than 

 formerly; instead, fortification with vitamin D is accomplished by the 



1 H. R. Rosenberg, Chemistry and Physiology of the Vitamins. Interscience Pub- 

 lishers, New York, 1945. 



^D. K. Tressler and J. McW. Lemon, Marine Products of Commerce. Reinhold 

 Publishing Corp., New York, 1951. 



3 H. N. Brocklesby, Chemistry and Technology of Marine Animal Oils with Par- 

 ticular Reference to Those of Canada. Fisheries Research Board of Canada, Ot- 

 tawa, 1941. 



^C. E. Bills, Chem. Revs. 3, 425 (1927). 



6 F. H. Young and H. D. Robinson, U.S. Pat. 2,136,481 (1938). 



6 J. C. Wallenmeyer, Mexican Pat. 35,140 (1934). 



7 H. Steenbock, Science 60, 224 (1924); U.S. Pat. 1,680,818 (1928). 



