THE CHEMISTRY OF COFFEE 177 



portant constituents of the coffee-cherry substance and that it yields 

 mannose on hydrolysis. 



The following table regarding the composition of the ash of 

 coffee is compiled from information given in the U. S. Dept. Agric. 

 Div. of Chem., Bull. 13 pt. 7 (1892) 904. 



Coffee Ash. 



Constituents Mocha Rio Java 



Chlorine (Cl) 1.25 0.48 O.73 



Ferric oxide (Fe.OJ 0.89 1.77 1. 16 



Lime (CaO) 7.18 4.94 4.84 



Magnesia (MgO) 10.68 10.60 ii-35 



Phosphoric Acid (P^O.) 12.93 ii-53 14-09 



Potash (K^) ...;.!' 59.84 63.60 62.08 



Sand 1.44 1.34 0.74 



Silica (SiO.) 0.88 0.69 0.91 



Soda (Na,0) 0.48 0.17 



Sulphuric Acid (SO3) 4.43 4.88 4.10 



100.00 100.00 100.00 



Rochleder found the fat of coffee contained glycerides of palmitic 

 acid and an acid of the composition C12H04O0. Tretzel found that 

 the glycerides of palmitic, stearic, and oleic acids, and free dihydroxy- 

 stearic acid were present. 



Coffee Fat Values (according to Tatlock and Thompson). 



Spec. 

 Coffee Grav. 



Raw 



Roasted 0.9354 



Me5^er and Eckert have separated a fatty oil and a wax from raw 

 cofiee. They give the following table: 



Oil Saponifica- 

 Coffee tion Value Iodine Value 



Raw 160 to 182 90.1 to 91.2 



Fatt}^ acids present were mainly linoleic, palmitic, and carnaubic 

 acids, together w4th traces of oleic, daturic, and caproic acids. The 

 wax contained carnaubic acid in combination with a resin alcohol. 

 The unsaponifiable matter of the coffee fat included Phytosteral. 





Saponi- 





Iodine 



fication 



Unsapon- 



Value 



Value 



ifiable 



99.0 



179-5 



5.26 



99.0 



179.5 



5.51 



