CAROTIN, THE PRINCIPAL YELLOW PIGMENT OF MILK FAT 349 



After studying the carotin pigment, more carbon bisulphide was 

 run through the column shown in Figure II. until the lower green zone 

 was washed out. This was removed from the test tube and the stream 

 of carbon bisulphate continued until the two least adsorbed orange-yel- 

 low zones had been washed out. The carbon bisulphide solution of these 

 pigments had a golden yellow color with a faint green tinge. Before 

 the spectroscope the solution showed two chlorophyll bands in the 

 red, and three very clear bands in the blue. (See Table 2.) 



The carbon bisulphide was evaporated off and the residue dis- 

 solved in hot eighty per cent alcohol, the phytosterol which precipi- 

 tated on cooling being filtered off. The alcoholic filtrate was now 

 extracted with petroleum ether (b. p. 30-50 C), which took up some 

 green color. This was continued until no more green was extracted. 

 The golden yellow alcoholic xanthophyll solution was examined in 

 the spectroscope. No chlorophyll bands were visible but only two 

 strong bands in the blue and sharp end adsorption. 



The alcoholic solution was now saponified with potassium hydrox- 

 ide and the diluted soap extracted with ether in the usual way. The 

 color immediately went into the ether, the separation being complete 

 with one extraction. After washing free from alkali the ether was 

 evaporated. A portion of this residue as well as a portion of the res- 

 idue of the solution before saponification, showed a beautiful green- 

 ish blue coloration with concentrated H 2 SO 4 . The remainder when 

 dissolved in alcohol, gave a golden yellow solution showing two bands 

 and end absorption. (See Table 2.) 



TABLE 2. ABSORPTION BANDS OF ALFALFA XANTHOPHYLLS 



A little HC1 added to a portion of the alcoholic solution gave no 

 blue coloration. Solubility tests on the saponified pigment showed 

 that petroleum ether extracted no color from an alcoholic solution on 

 dilution with a little water, while carbon bisulphide extracted about an 

 equal portion. 



