CLASSES ol l\\^ 13 



CLASSKS OK J ATS 



There are two great classes (jr groups of fats [present in the 

 butter, namel}': 



(i) \'olatile and Soluble, 



(2) Xon-volatile and Insoluble. 



It was previous!}' stated that little i^ known concerning the 

 way in which the fatty acids are combined with g!_\xerine in the 

 milk; but, for the sake of con\'enience, the fats will be referred 

 to as if they existed as separate gh'cerirleb of fat. 



The terms " \'olatile " and " Xon-\-olatile " are applied to 

 the glycerides of fat, or to the fats as the}' exist in butler. Strict)}' 

 speak.ing, this is not proper, as the\' dn not a^.-ume the A'olatile 

 characteristics until the gh'cerine st-jjarate? from the fatt}' acids; 

 it is on]}' then that llie latter become A'dlatile. 



Volatile Fats. — The first group, or the \'olatile fats include 

 l"jut}'rin, caproin, caprA'lin, caprin, and laurin. ButA'rin i.•^ the 

 one present in the largest proportion. Laurin and caprin are 

 partial]}' non-volatile. Butyrin is the most important fat 

 belonging to the volatile group. It is the uKjst important quan- 

 titati\'el}' and also cjualitatiA'el}', So far as is known, bul}'rin 

 is the least stable of an}- of the butter-fats. Unrler normal ccjn- 

 ditions, so long as the fatt}' acid remains in cijmbination with the 

 glycerol, it is neither A'olatile nor soluble in water; but as soon 

 as separation takes place, due tcj the action <jf micr(j-organisms, 

 or to the efTect of light and air, it becomes A'(jlalile, and escapes 

 in the form of gas. 



It is also claimed that the,--e A'olatile fats liaA'e the sfjecial 

 properties of absorbing odors and gases to a greater extent than 

 any of the other fats. This absorption takes place when fat 

 comes into contact with the undesirable taints. For this reason 

 it is essential that milk, cream or butter be kept a^A'a}' from an}' 

 foreign, undesirable odors. These taints ma}' also be imparted 

 to the fat before the milk is drawn. If the coa\' is fed on unde- 

 sirable food, such as turnips, onions, garlic, etc., the niilk from the 

 cow assumes undesirable characteristic fla^'ors which can easily be 

 recognized in the finished profluct. On the other hand, such 



