350 PROCEEDINGS OF SECTION B. 



7.— THE ANALYSTS OF MALT EXTRACT. 

 By E. S. RICHARDS, B.Sc. 



The production of concentrated malt extracts has greatly increased 

 in recent years. It is already Avell known as a food ami also a valuable 

 digestive agent, but it is now beginning to command attention in some 

 of the fermentation industries, notably in the process of breadmaking 

 an.d manufacture of alcohol. 



Hence a knowledge of its constituents is of importance. Very 

 few analyses of malt extracts have been published. Ling and Rendle 

 ("Analyst," xxix., p. 244) have published the results of an examination 

 of nine samples. From these results it will be seen that dextrose occurs 

 as an invariable constituent, as much as 22 per cent, being found. 

 Previous to this, the presence of dextrose was taken to indicate adultera- 

 tion with glucose syrup. 



Li the following list of analyses the dextrose varies from 10-9 per 

 cent, to 26-2 per cent. They are results obtained from commercial 

 extracts obtainable on the market. No. 3, which shows 24-1 per cent, 

 dextrose was known to be free from glucose syrup, its manufacture 

 being carefully followed. Harrison and Gair gave the results of an 

 examination of 13 samples at the British Pharmaceutical Conference 

 held at Birmingham in July, 1906. But in their results they attribute 

 the whole of the reducing power to maltose, totally neglecting the effect 

 of dextrose. 



In the analyses published by Ling and Rendle the dextrose was 

 determined as glucosazone, the maltose being calculated from the 

 reducing power, less that due to the amount of dextrose found, whilst 

 the dextrin was calculated from the rotatory power after deducting 

 that due to dextrose and maltose. In following out this method it 

 was found that in the cases of some of the extracts under examination 

 the observed rotation was insufficient to account for even the dextrose 

 and maltose, while at the same time there was certainly an appreciable 

 amount of dextrin present, e.g., in sample No. 3 the specific rotation 

 for the dextrose and maltose found should be 61°'9, while the observed 

 specific rotation is only 60°'6. Evidently in the extract in question 

 the total rotation is not the sum of the rotations of the constituents. 

 To overcome this difficulty the dextrin was estimiited by Wiley's method 

 of oxidising the sugars, maltose, and dextrose to optically inactive 

 compounds, and then determining the dextrin left by its rotation. The 

 methods of analysis adopted were as follows : — 



Water. 



Brown, Millar, and Morris have shown (J.C.S. Trans., 1897, p. 73) 

 that the drying of such solutions is a very laborious operation, and it 

 requires very special processes to expel the last traces of moisture. 

 Also, unless these special processes are adopted, the results obtained 

 by determining the specific gravity of the solution are quite as accurate 

 if not more so. To determine the percentage of water present the 



