CAROTIN, THE PRINCIPAL YELLOW PIGMENT OF MILK FAT 357 



A wide variety of fats of different color, from different breeds of 

 cows and produced under widely different conditions of feeding, etc., 

 were available for this study. The technique of these experiments 

 was identical with that used for the high colored fat from the 

 Jersey cow on grass recorded in Experiments I and 2 above. 



The Pigments of Light Colored Fats. The character of the pigment 

 in three light colored fats was tested. The fats represent three 

 subsequent periods in a feeding experiment of a pure bred Ayrshire 

 cow in which the color was practically eliminated from the butter 

 fat. (See Table 13 of feeding experiments for record of this experi- 

 ment.) The color of the fat and the character of the pigments 

 are shown in the following Table 7. 



TABLE No. 7. 



Color of Fat 



Yellow Red 



6.0 



2.5 



1.4 



1.0 



0.7 



0.5 



Character of Pigments. 



Petroleum ether quant, extracted cholesterol-free pig- 

 ment from 80 per cent alcohol. 



Solubility test showed carotin and xanthophylls. 



Chromotogramm of xanthophylls showed adsorbed 

 yellow constituent and unadsorbed orange zone. 



Pigment from 240 gm. fat had color of 35 yellow, 1. 

 red. Solubility test showed both carotin and xan- 

 thophylls, as did also absorption bands. 



The Pigments of Butter Fat After Carrot Feeding. The fat tested 

 was taken during a carrot feeding experiment with the same cow 

 used in the above experiments. This feeding experiment directly 

 followed the third period of very light colored fat. The color of the 

 fat was 28 yellow and 1.4 red. Solubility tests on the pigment 

 showed carotin and a very small amount of xanthophyll. The petro- 

 leum ether soluble part of the pigment gave a CS 2 chromotogramm 

 of a single unadsorbed rose colored zone. The filtered pigment 

 showed three well defined absorption bands. I, 225-245; II, 263- 

 283; III, 301-320. 



