BUTTER 93 



sulfuric acid and four parts glacial acetic acid. 

 The contents of the tube are then heated almost 

 to boiling and thoroughly mixed by violently 

 agitating the bottom of the tube. When now 

 allowed to stand and separate, the lower layer of 

 mixed acids will be strongly colored wine-red if 

 the azo-color be present. Pure butter-fat im- 

 parts no color to the acids, or, at most, only a faint 

 brownish tinge. 



Turmeric and Annatto. — Martin's test will 

 usually be satisfactory: 2 c.c. carbon disulfid 

 are mixed with 15 c.c. of alcohol, by adding small 

 portions of the disulfid to the acohol and shaking 

 gently; 5 grams of the butter-fat are added to 

 this mixture in a test-tube and shaken. The 

 disulfid falls to the bottom of the tube, carrying 

 with it the fatty matter, while any artificial 

 coloring-matter remains in the alcohol. The 

 separation takes place in from one to three 

 minutes. If the amount of the coloring-matter 

 is small, more of the fat may be used. If the 

 alcoholic solution be evaporated to dryness and 

 the residue treated with concentrated sulfuric 

 acid, annatto will be indicated by the production 

 of a greenish-blue color. With many samples 

 of oleomargarin, a pink tint will be produced, 

 which indicates an azo-color. 



Palm oil has been used as a coloring agent in 

 butter-substitutes. Crampton & Simons have 



