IMPROVED METHODS FOR FAT ANALYSIS. 



127 



forms a tetrabromide, it generally absorbs only 1 or possibly 2 halogen 

 atoms. The double-linked carbon atoms may be considered the ethylene 

 type, and the triple-bonded an acetylene linkage. The glycerides act 

 similarly to the free acids and absorb three times as many atoms (tri- 

 glycerides). 



In those cases where only one such acid or glyceride is present its per- 

 centage can be readily calculated from the iodine number by dividing by 

 the theoretical absorption or by means of a factor. 



Oleic acid 

 Olein = 



I 



C17H33COOH 

 61 



2 X126.92 

 282.272 



761.52 



(CnHsaCOOaCaHsl S84.832 



= 0.89927 



= 0.86064 



In a similar manner the following figures for theoretical absorption 

 were deduced for the acids and glycerides enumerated below: — 



Where there are two unsaturated acids (or glycerides) present (x and y) 

 of known iodine absorption (c and d), if the percentage of the mixture (P) 

 and the iodine number (W) of the fat have been determined, the per cent, 

 of each acid (or glyceride) can be calculated by formula. 



x+y=P 

 cx+dy = .01 W2 



^ _ .01 W -dP 

 c-d 



» 3(Ci7H33COOH)+C3H2 or 3m+38.016. 



*The fsQtor 0.01 converts the iodine number to the same basis as the figures for theoretical ab- 

 sorption stated in the previous table. 



