198 BUTTER 



189. Determination of Total Solids not Fat, 



The solids other than fat present in butter include casein, milk 

 sugar, lactic acid, and ash constituents (NaCl, etc.), and the 

 estimation of the percentage is of importance in the detection of 

 adulteration by certain methods that increase the total solids other 

 than fat. For example, adulteration with milk powder would 

 increase the percentage of milk sugar, etc. 



From lo to 15 grams of butter are weighed out into 

 a porcelain basin, and melted at as low a temperature as 

 possible. 



A few c.c. of dry ether is poured on to the butter, the 

 mixture thoroughly stirred, and the ethereal solution of 

 fat filtered through a filter paper that has been previously 

 extracted with ether, dried at 100°, and weighed. 



As much as possible of the residue insoluble in 

 ether should be retained in the basin, and treated 

 successively with further quantities of ether, which are 

 poured as before on to the filter paper. Finally, the 

 contents of the basin are well washed with ether into 

 the filter, which is then carefully folded up, into the 

 form of a cartridge, and extracted with ether in a 

 Soxhlet extractor for about half an hour, in order to 

 remove all traces of fat. The filter paper and contents 

 are then removed from the extractor, dried in the steam 

 oven, and weighed. The increase in weight will give 

 the amount of solids other than fat present in the 

 quantity of butter taken. 



190. Determination of Common Salt. 



The filter containing casein, NaCl, milk sugar, etc., 

 obtained after the determination of total solids other 

 than fat is fitted into a glass funnel of suitable size, 

 and the contents well washed with boiling water from 

 a wash-bottle into a small conical flask. 



The aqueous solution so obtained will contain milk 



