THE CLARIFICATION OR DEFECATION OF THE JUICE. 



4. Under similar conditions, sulphates, sulphites, oxalates, &c., retard 

 the rate of inversion. 



Effect of Glucose. The action of glucose on the inversion of cane sugar 

 is a peculiar subject, some investigators finding that glucose of itself caused 

 inversion, and others observing no effect. Geerligs 17 , in investigating the 

 subject, came to the conclusion that glucose of itself had no invertive action, 

 but that in the presence of neutral salts, such as chlorides, nitrates and 

 sulphates of the alkalies and alkaline earths, inversion occurred at the 

 temperature of boiling water, owing to a slight hydrolysis of the neutral salt 

 under the influence of the glucose. The writer 16 in investigating the same 

 subject failed to obtain any trace of inversion due to the combined influence 

 of glucose and neutral salts, when the latter were present in normal 

 concentration.* 



Inversion under Acid Salts. Salts of the heavy metals, such as zinc 

 sulphate, also cause the inversion of cane sugar. This has been chiefly studied 

 by Long 18 ; the inversion is ascribed to the partial hydrolysis of the salt, 

 thereby affording free hydrogen ions in solution. 



Inversion under the Influence of Enzymes. Besides chemical inversion under 

 the influence of acids and acids salts, cane sugar is inverted by the action of 

 certain ferments known collectively as enzymes. The enzyme most studied 

 is that secreted by yeast, and known as invertase. The properties of this body 

 were first investigated by 0' Sullivan and Thompson 19 , who found that the most 

 favourable concentration of the sugar solution was 20 per cent., that the optimum 

 temperature was 55 C. to 60 C., the enzyme being slowly destroyed at 65 C., 

 and instantaneously at 75 C. The action of invertase is greatly accelerated by 

 minute traces of acids. 0' Sullivan and Thompson found that the law of mass 

 action held for the action of invertase, a result not obtained by subsequent 

 workers until C. S. Hudson 21 showed that these had neglected to take into 

 account the mutarotation of the invert sugar formed. 



Another instance of enzyme inversion of interest to the sugar industry 

 was examined by Lewton-Brain 22 ; he found that the fungus connected with 

 the Red Rot of the Stem (Colletotrichum fakatum) secreted an invertase 

 capable of rapid inversion of cane sugar. 



Inversion and Manufacture of Consumption Sugars. 



It has already been stated that in the manufacture of consumption sugars it is 

 customary to work juices with an acidity reaching up to 20 c.c. decinormal 

 acid per 100 c.c. of juice. Sugar and water, even with acetic acid, at such 

 an acidity, would be very rapidly inverted at 100C. In the sugar house, 

 however, the system consists of sugar, water, acid and neutral salt ; the action 

 of the neutral salt decreases (under the ionic hypothesis) the concentration 



* Since the above was in type, Mr. Geerligs has suggested that the discrepancy in 

 the results was due to the fact that neutral inorganic salts only invert sucrose in the 

 1 resence of glucose in the case where they occur in feeble concentration. Highly con- 

 centrated salt solutions are without invertive action. 



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