148 THE BOOK OF BUTTER 



112. Natural color. — The natural coloring matter in 

 butter comes from the feed. Palmer and Eckles ^ state 

 as follows : 



" The fat of cows' milk owes its natural yellow color to 

 the pigments carotin and xanthophylls, principally carotin, 

 the well-known, wide-spread, yellow vegetable pigments 

 found accompanying chlorophyll in all green plants. 



" The carotin and xanthophylls of milk-fat are not 

 synthesized in the cow's body, but are merely taken 

 up from the food and subsequently secreted in the 

 milk-fat. 



" There is some difference among different breeds of 

 dairy cows in respect to the raaximum color of the milk- 

 fat under equally favorable conditions for the production 

 of a high color. Each breed of cows, however, will under- 

 go the same variation in color of the milk-fat which follows 

 a withdrawal or addition of carotin and xanthophylls, 

 especially carotin, to the feed. Under some conditions, 

 also, the apparent breed characteristic largely disappears. 

 The popular opinion in regard to the breed characteristic 

 has been overemphasized, and statements in regard to 

 it should in the future be qualified with a statement of 

 the conditions of feed, etc. 



" Under normal conditions cows of all breeds produce 

 very high colored milk-fat for a short time after parturi- 

 tion. The pigments of the fat at this time are identical 

 with the normal pigments of the fat. Their increase at 

 this time is probably due to the physiological conditions 

 surrounding the secretion of the milk of the freshening 

 animal." 



' Palmer, Leroy S., and Eckles, C. H., The Principal Natural 

 Yellow Pigment of Milk Fat, Part II, Univ. Mo. Agri. Exp. 

 Sta,, Res. Bui. 10, p. 386, 1914. 



