CTIM POSITION" OF liUTTEK-FAT 



15 



fats, the fats witli a low mellini^'-point \v(jul(I Tiielt fir^t, and leave 

 the remainfler in an unmeUed condition. Sui h i> not the ease. 

 Butter-fat in this resi)eet ljeha\'es a ,ti:oofl deal lif;e difTerent 

 metals with (hlTerent fusing-points. When the}' are mehed anrl 

 mixed together, eooled and then remelted the}' assume a eommon 

 melting-jjoinl. liulter-fat behaws in the same way. It melts 

 at a temperature of 91" to (/>""' V. 



As the bod}' temperature of cows Tabout loi^" F.) is above this 

 temperature, the fat globules are present in the milk in lif4uid 

 form when it is farst drawn. A peculiarit}' about these fat- 

 globules in milk is that the milk and fat ma}' be cooled below the 

 melting-point of the fat of butter without the fat-globules in milk 

 being solidified. It recjuires a temperature of between 60^'' and 

 78^^ F. before the fat-globules in milk begin to solidify. When 

 these small fat-globules are caused to unite, as during the churning 

 process, the}' solirlif}' at a higher temperature. This behaA'ior of 

 the fat in milk e\'iflentl}' must be flue to a relati\'e change in the 

 position of the molecules of fat during the process of cooling and 

 warming. Xo definite explanations, so far as is known, have been 

 given for this condition of the fat. 



The non-\'olatile fats founrl in butter-fat are practicalh' the 

 same as those found in other animLil fats. 



Composition of Butter-fat. -In his " Dairy Chemistr}-," 

 Richm(jnd gi\'es the following composition of butter-fat, rej)re- 

 senting the mean results obtained b\' different obser\'ers: 



Fat. 



S per rent \olatilc. 



02 per rent non-\'<)latile. 



Per Cent 



■ Butyrin 3 85 



Caproin ,3 60 



Caprylin 55 



" Caprin 1.9 



Laurin 7.4 



Myristin 20, 2 



Palmitin 25 7 



Stearin 1.8 



Olein 35 



Richmond also gives the percentage of gh'cerine and fatty 

 acids in each of the different fats, as follows: 



