HO The Philippine Journal of Science 



er. Acetic acid failed to give like results when used by us, 

 and were a zymogen present this acid should activate it. 



CONCLUSIONS 



The color tests with decolorized fuchsin and with diazobenzene 

 sulphonic acid are not reliable tests for rancidity. High acid- 

 ity of oils is not coterminous with rancid ty. Steam distillation 

 removes rancidity, but makes very slight changes in the acidity; 

 neutralization with alkali and washing removes the acidity but 

 not the rancidity. The Reichert Meissl number in the few cases 

 studied indicated no close relationship between this constant 

 and the rancidity. No conclusions could be drawn from the 

 magnitude of the iodine value. The soluble fatty acids show 

 a relationship which indicates that this constant might be of 

 value in an estimation of the rancidity of an oil. The acetyl 

 value may be of value in indicating rancidity, but is not a meas- 

 ure of the degree of rancidity. The oxidizability number ap- 

 pears to be a good confirmatory test for rancidity, but a few 

 samples of oils undoubtedly rancid gave low oxidizability values. 

 However, where the value was high, the oil was always rancid. 



Further work on the acetyl value, the oxidizability Value, the 

 soluble fatty acids, and the test for the presence of oxidizing 

 enzymes and their action should yield valuable data. 



Control samples have been stored for the study of these 

 constants. 



