532 



COMPOSITION AND PROPERTIES OF BUTTER 



Normal variations in the percentage of butterfat in butter 

 are due to its natural mechanical firmness which determines its 

 power to absorb and hold water and by the process of manu- 

 facture. The mechanical firmness of the butterfat is dependent 

 on such factors as season of year, which largely controls the 

 period of lactation and the character of the feed, and on locality 

 which determines the breed of cows and, in part, the character 

 of their feed. 



Butterfat is the fat of milk, milk fat is a natural compound 

 of several different fats which vary in their properties. The 

 chief of these fats are the olein, palmitin, myristin, stearin, 

 laurin, butyrin, caproin, caprylin and caprin. 



These fats are present in the form of a chemical combination 

 of glycerol (glycerin), as the base, and of one or more fatty 

 acids, such as oleic, palmitic, myristic, stearic,-lauric, butyric, 

 capronic, caprylic and capric acids. 



These fats are spoken of as the glycerides. The proportion 

 in which these glycerides, or fats, are present in the mixed milk 

 fat varies according to breed, period of lactation and feed of 

 the cows, hence analyses of milk fat derived from different 

 sources are somewhat at variance. Richmond 1 shows the follow- 

 ing composition of milk fat: 



Table 72. Composition of Milk Fat. 



1 Richmond, Dairy Chemistry. 



