COMPOSITION OF MILK 19 



There is usually three and a half times as much 

 casein as albumen in cow's milk. 



Ash. The ash of milk is the mineral matter that 

 is left after burning off the organic matter. It is 

 necessary chiefly for the building up of the bony 

 framework of the growing animal. It is complex 

 and includes the following: Calcium, sodium, potas- 

 sium, magnesium, iron, phosphorus, and chlorine. 

 Some of these minerals exist in solution in the milk, 

 while others are in suspension in minute particles 

 and may be filtered out with a porcelain filter, which 

 could not be done if they were in solution. The 

 chemical form in which some of these minerals 

 exist in the milk has an important bearing in cheese 

 making. Heating milk sufficiently changes the 

 chemical combination of some of the mineral salts 

 so that rennet will not coagulate the milk. 



Coloring matter. The coloring or lactochrome of 

 milk is associated with the palmitin fat. The 

 amount of coloring matter varies with different 

 breeds and different individuals at different seasons 

 of the year chiefly because of the difference in the 

 feeds characteristic of these seasons. Succulent 

 feeds, such as pasture grass, silage, carrots, and 

 beets, increase the coloring slightly. 



