BUTTER 6 1 



and the test is not applicable to butter which has been melted 

 and reworked (renovated or process butter). 



Saponification test. — An alcoholic solution of sodium hy- 

 droxid, boiled up with butter, and then emptied into cold 

 water, gives a distinct odor of pineapples, while olcomargarin 

 gives only the alcoholic odor. 



Renovated Butter. — So-called "process" or "renovated" 

 butter, made by rendering old or inferior samples, purifying 

 the fat, coloring, salting, and molding it, is now a familiar com- 

 mercial article. Process butter when heated in a dish sputters 

 with but little foaming, as does olcomargarin; but yields with 

 alcoholic soda the pineapple odor, as does butter. The fat of 

 process butter gives refractometric data and Reichert-Meissl 

 number similar to those of ordinary dairy butter, but is said 

 to give a different figure with Valenta's test. If, therefore, 

 a sample sputters in the pan, but gives the other reactions for 

 butter, as just noted, it may be assumed to be process butter. 

 Hess & Doolittle state that the curd of process butter has 

 characteristic qualities, and propose the following method for 

 detecting it: 



50 grams of the sample are melted in a beaker at about 

 50°. Ordinary butter yields a clear fat almost as soon as 

 melted, while with process butter the fat may remain turbid 

 for a long while. When the curd has largely settled, as much 

 of the fat is poured off as possible, and the remaining mix- 

 ture is thrown on a wet filter, by which the water will drain 

 away, carrying the soluble proteids and salt. A few drops of 

 acetic acid are added to the filtrate and the mixture is boiled. 

 The filtrate from ordinary butter gives a slight milkiness, but 

 that from process butter gives a flocculent precipitate. Quan- 

 titative examination is made by dissolving 50 grams of the 

 sample in ether; if it is ordinary butter, the curd is so finely 

 divided that it remains suspended for some time. As much 

 as possible of the solution is decanted and the mass transferred 



