ISOMALTOSE, MALTOSE, GLUCOSE, SACCHAROSE, ETC. 



143 



and oil cooling the filtered solution another osazone was obtained which was identical with 

 the osazone prepared from gallisin. Frequent mention is made of isomaltose in the subse- 

 quent literature on the products of starch digestion. 



Tollens (Ann. d. Chem. u. Pharm., 1890, ccLVii, 150) prepared from corn a syrup 

 from which a sugar crystallized, which he states had all the properties of saccharose. In 

 analyses of sweet corn at different stages of growth he found saccharose, glucose, dextrin, 

 and other bodies. By the action of butj'ric acid ferment (B. amyhhacter) , Villiers (Compt . 

 rend., 1891, cxii, 536) found among other products a small amount of a crystalline carbo- 

 hydrate which was converted into glucose by warm hydrochloric acid; and there was also 

 another product which resembled cellulose, which was converted into glucose by acid. 

 Lintner (Zeit. f. d. ges. Brauwesen, 1891, 281), in experiments with beer-worts, to which 

 he added phenylhydrazine acetate, recorded that an osazone was formed which in crystal- 

 line properties and melting-point was identical with the isomaltose of Fischer. Later, he 

 and Diill prepared isomaltose from the products of the action of diastase on starch. 



The saccharine products of the fermentation of glucose by means of piu'e cultures 

 of Sacch. cerevisioe and iS. apunculatus were examined by Reinke (Zeit. f. Spiritusind., 1892, 

 79). His results were such as to indi- 

 cate that only glucose was fermented. 

 The dextrin present was determined 

 by inversion with hydi'ochloric acid, 

 while the percentage of isomaltose was 

 determined by the residual reducing 

 power after fermentation. The fig- 

 lU'es are recorded m table 12. 



The existence of Cuisiiiier's glu- 

 case (p. 141) was denied by Lintner (Wochenschr. f. Brauerei, 1889, v, 1038) because he 

 failed to find glucose as well as maltose in experiments similar to those of Cuisinier. In a 

 later research, Lintner (Zeit. ges. Brauw., 1892, xv, 123) acknowledges his error, and notes 

 that while barley and wheat contain but little glucase, corn contains much. He prepared 

 glucose by mixing a thin starch-paste with corn-meal, and keeping the mixture at 60" for 

 30 to 48 hours. The filtrate if concentrated will crystallize. The amount of glucose, he 

 states, is small in comparison with maltose. In another article published at the same time, 

 Lintner and Diill (Zeit. ges. Brauw., 1892, xv, 145) give a detailed method for the prepa- 

 ration of isomaltose, by which a pure isomaltose can be obtained, and in quantity represent- 

 ing 20 per cent of the original starch. This sugar they found to ferment with yeast much 

 more slowly than maltose. It had the same specific rotatory power as maltose (a)D = + 140°, 

 but its reducing power was found to be only 83 per cent of that of maltose. Its osazone 

 melted at 150° to 153°, while that of maltose melts at 206°. 



The sole products of the action of diastase on starch are, according to Schifferer (Neue 

 Zeit. Rub. Zuck. Ind., 1892, xxix, 167), dextrin or dextrins, isomaltose, and maltose. The 

 maltodextrin of Brown and Morris he believes is probably a mbcture of 67 per cent of dextrin 

 and 33 per cent of isomaltose, while the maltodextrin of Herzfeld he regards as consisting of 

 26 per cent of dextrin and 74 per cent of isomaltose, and he thinks that Herzfeld must have 

 unknowingly fractionated isomaltose from his so-called maltodextrin. Schifferer states that 

 isomaltose is always formed during the saccharification of starch as long as dextrin is 

 present; and that at the hmit of the reaction the preparation does not have a reducing 

 power corresponding to 80 to 81 per cent of maltose, but to 60 to 68 per cent. 



Glucase was investigated by Geduld (Wochensch. f. Brauerie, 1892, vii, 620), who 

 found that this enzyme exists in ungerminated cereals in both soluble and insoluble forms, 

 and in germinated grains in an insoluble form; that it does liquefy starch-paste; that it 

 has only a \'ery slight action on starch, a gi-eater action on dextrins, and a very energetic 



