336 



BUTTER. 



Heat Evolved by Hydrolysis by Sulphuric Acid. 



The Maumend Test. — When fats are acted on by strong 

 sulphuric acid a series of reactions takes place. The fat is first 

 split up to fatty acids and glycerol, which combines with the 

 sulphuric acid. The saturated fatty acids (stearic series) are not 

 further affected, but the unsaturated fatty acids undergo sul- 

 phonation and other changes. Of these, the oleic series, which 

 has only one saturated bond, is acted on to a less degree than 

 the linolic and linolenic series, which contain two or three bonds 

 respectively. Each of the actions which takes place evolves 

 heat, and, by measuring the rise of temperatures which takes 

 place, an index of the total amount of heat evolved is obtained. 



Modification by Thompson and Ballantyne. — This test is 

 due to Maumene, who measured the heat evolved on mixing 

 10 c.c. of sulphuric acid with 50 grammes of ^n oil or fat. His 

 original method was faulty, in that he did not rigidly prescribe 

 any strength of acid nor form of apparatus. Thompson and 

 Ballantyne propose to compare the heat evolved on mixing 10 c.c. 

 of sulphuric acid with 50 grammes of oil or fat with that evolved 

 by mixing 10 c.c. of the same acid with 50 grammes of water 

 in the same vessel. Taking the heat evolved by the water as 

 100, they term the figure obtained the " Specific Temperature 

 Reaction " of the oil or fat. This method gives a very fair 

 means of correcting for the differences of temperature observed 

 when working with acids of differing strength and in different 

 apparatus, and is convenient in practice. 



The author has examined with some care the results obtained 

 by the use of acids of different strengths. The following series 

 will show that the effect of strength of acid can be corrected by 

 a very simple calculation. These results were obtained with a 

 pure olive oil. 



TABLE LXXIX. 



