34 MISSOURI AGRICULTURAL EXPERIMENT STATION, BULLETIN NO. IO 



been reported. It is usually classified in the current text books, 1 

 however, according to Krukenberg's classification of lipochromes. 



In view of the commercial importance attached to the butter fat 

 pigment and especially in view of the results of the most recent inves- 

 tigations in this field, it was recognized that a thorough investigation 

 of this pigment would be of great value both from a scientific as well 

 as a practical standpoint. 



The present investigation was therefore undertaken for the pur- 

 pose of classifying the butter fat pigment as a true lipochrome and 

 also with respect to its relation to the carotin and xanthophylls of 

 green plants. It was also the purpose of the investigation here 

 recorded, to gather as much information as possible relative to the 

 influence of certain factors upon the color of butter, among which may 

 be mentioned the character of the ration and the breed of the cow. 



METHODS OF ISOLATION, 



The statement is frequently met in the literature 2 and in the text 

 books and works 8 on oils and fats, that the pigment of butter or butter 

 fat appears in the unsaponifiable extracts along with cholesterol and 

 other substances. 



A number of methods for obtaining the unsaponifiable matter of 

 butter fat are available and several were tried. The method finally 

 adopted for the isolation of the crude pigment was to saponify the 

 butter fat with a twenty per cent solution of alcoholic potash, using 

 2, c. c. for each gram of fat. Saponification was allowed to continue 

 for one half to one hour at the temperature of the boiling solution. 

 The soap was dissolved in three volumes of distilled water. After 

 cooling, the solution was shaken with an equal volume of pure ether 

 in a separatory funnel. The extraction was repeated with a fresh 

 volume of ether equal to one-half the volume of the soap solution. 

 It was found that this procedure would leave the soap colorless, if 

 no aldehyde resins had formed during saponification or none of these 

 colored bodies had been present in the alcoholic potash previous to its 

 addition to the fat. The ether extract containing the pigment and 

 other unsaponifiable matter was now freed from alkaline soap, by 

 shaking many times with excess water, carefully at first to avoid 



1. Such as Hammarsten, "Text Book of Physiological Chemistry" and 

 Schaefer, "Text Book of Physiological Chemistry", etc. 



2. Kirsten: Zeit. Nahr. Genuss. 5, p. 833 (1903). 



3. Lewkowitsch: "Oils, Fats and Waxes." Vol. I, p. 371, (1909 Edition). 



