144 DIFFERENTIATION AND SPECIFICITY OF STARCHES. 



action on maltose, the end-product being dextrose; that the optimal temperature is between 

 56 and 60, and that above 70 it is inert ; and that it is probably widely distributed and 

 an important diastase. Geduld's results received sujiport in the investigations of Jalowetz 

 (Wochensch. f. Brauerei, 1892, viii, 1264), who found evidence of the existence of glucase 

 in cereals other than barley and corn. 



Morris (Trans. Inst. Brew., 1893, v, 132), however, failed to note any formation of 

 glucose in experiments with maltose solution and aqueous extracts of corn, barley, rye, 

 oats, and wheat, both malted and unmalted, with the exception of corn malt. He looks 

 upon the results of Lintner and Jalowetz as fallacious because they ignored the existence of 

 glucose and other sugars in the extracts they emj^loyed, and he believes that the enzyme 

 is peculiar to corn and possibly other cereals as yet not examined, and that it does not 

 occur as a normal or frequent constituent of barley or barley malt. 



Lintner and Diill (Ber. d. d. chem. Gesellsch., 1893, xxvi, 2533), in an investigation 

 of the degradation of starch by the action of diastase, record that the products of digestion 

 are amj'lodextrin, erythrodextrin, achroodextrin, isomaltose, and maltose. The so-called 

 amyloins of Brown and Morris (page 115) they hold consist partly of mixtures of dextrin 

 and isomaltose and in part identical with isomaltose. Isomaltose they found has a reducing 

 power equal to 80 per cent of that of maltose; its rotatory power they give as (a)r, = + 140, 

 and the melting-point of its osazone 150 to 153. Maltose they believe is formed from 

 isomaltose, which they think leads to the conclusion that dextrins and starch are composed 

 of isomaltose groups. 



The sugar products formed by the actions of animal enzymes were studied by Kiilz 

 and Vogel (Zeit. f. Biologic, 1895, xxxi, 108). They used a 5 per cent solution of rice 

 starch, and determined the sugars present by means of their osazones. They found that 

 human parotid saliva formed isomaltose; that mixed human saliva formed isomaltose at 

 first, then maltose, with traces of glucose; that dog's saliva formed isomaltose; and that 

 pancreas of the ox also formed isomaltose. With liver glycogen instead of starch, parotid 

 saliva formed 1 part of isomaltose to 2 parts of maltose; with muscle glycogen, saliva in 

 small quantity yielded isomaltose with a little maltose and glucose, but a larger quantity 

 ga^'e only maltose. With liver glycogen, pancreas gave isomaltose and a trace of maltose; 

 and with muscle glycogen, there were formed isomaltose with a trace of glucose. 



Glucose, isomaltose, and maltose were found to be the sugar products of starch de- 

 composition by Hiepe (The Country Brewer's Gazette, 1893, 1894; Jour. Soc. Chem. Indus- 

 try, 1894, xiii, 267). Hiepe used several tj'pes of yeast, and noted that the percentages 

 of isomaltose formed varied widely in relation to the kind of yeast. He shows that the 

 amyloins are not indi\'iduals but mixtures. One of these bodies subjected to an elaborate 

 process of fractional precipitation by alcohol showed the presence of glucose, maltose, 

 isomaltose and dextrin. 



In a study of the differences in the products of starch conA^ersion by the action 

 of acids and diastase, Lintner and Diill (Ber. d. d. chem. Gesellsch., 1895, xxviii, 1522) 

 ascertained that isomaltose and glucose were produced with acid, while with diastase 

 there were isomaltose and maltose. Lintner (Zeit. f. ges. Brauw., 1895, xvii, 173, 414) 

 investigated the action of enzymes on isomaltose and maltose. He found that the conver- 

 sion of isomaltose into maltose did not go on to completion, sometimes only 30 per cent 

 being changed. He also notes that yeast powder gave rise to a very active formation of 

 glucose, that a watery extract is less effective, and that isomaltose is more readily affected 

 than maltose. He believes with Bau (Wochenschrift f. Brauerei, 1894, x, 1366; 1895, xi, 

 431) and Munche {ihidum) that isomaltose may consist of two stereoisomeric forms of iso- 

 maltose which differ in fermentability. Prior (Bayerisches Brauer- Journal, 1895, 193) holds, 

 to the contrary, that there are not two isomerides, and that Liutner's isomaltose is a homo- 

 geneous substance. Lintner is of the opinion that the ferment which hydrolyzes maltose 



