DIFFERENCES IN PRODUCTS OF ACID AND ENZYMIC ACTION. 



151 



value because pancreatic juice has a scant and incomplete action on them, wliile on the 

 other liand the dextrins formed by malt are easily transformed by diastases, as shown by 

 Soxhlet and Stutzer. 



A comparative study of the products of diastatic and acid degradation of starch was 

 made by Lintner and Diill (Ber. d. d. chem. Gesellsch., 1893, xxvi, 2533; 1895, xxviii, 

 1522). In the first research they subjected starch to the action of air-dried malt, varying 

 the amount, and stopping the digestion at the 



necessary point by boiling, and then repeatedly Table 13. 



fractionating the product with alcohol. In the 

 second investigation they used oxalic acid instead 

 of enzyme. Table 13 is a statement of the prod- 

 ucts obtained in the two cases. 



They state that, judging from their experi- 

 ments, acid and diastatic products of the same 

 molecular weight would yield the same products 

 and behave similarly upon the addition of more 

 acid or enzyme. Even though the dextrins are 

 alike, and even though the erythrodextrin II a 



and II /8 were also obtained with diastase, the only difference between the two hydrolytic 

 processes would be that in the acid process no maltose but isomaltose is obtained and 

 glucose appears as the end-product, and with the other maltose appears as the end-product. 



Eolfe and Defren (Jour. Amer. Chem. Soc, 1896, xviii, 869) found that only three 

 carbohydrates are present during acid hydrolysis, namely, dextrin, maltose, and glucose. 

 They believed that the products of acid and enzymic activities are the same. 



Petit (Compt. rend., 1897, cxxv, 309, 355) records that the saccharine products of 

 dextrin digestion differ somewhat according to the decomposing agent, the period of action, 

 and the temperature. 



The torrefaction dextrins of commerce can be distinguished, according to Henderson 

 (Inaug. Diss., Munich, 1897; Jour. Soc. Chem., 1898, xvii, 591), from those obtained 

 by the actions of diastase and acids by then- containing a more or less large propor- 

 tion of substances of low rotatory and reducing power, so that the dextrins formed 

 by these methods can not be considered identical. Henderson states that generally 

 speaking the same dextrins are formed by the actions of diastase and acids, although 

 with diastase dextrins are produced which resist further action of diastase. These 

 dextrins, he believes, have the composition of achroodextrins I and II of Lintner and 

 Diill. The possibility of isomaltose being included among the resistive products, he 

 states, is to be recognized. 



The reactions with acids were found by Syniewski (Ber. d. d. chem. Gesellsch., 1898, 

 XXXI, 1791) to proceed farther in the formation of glucose than with enzymes. Experi- 

 menting with soluble starch prepared by the agency of sodium peroxide, he noted that 

 with hydrochloric acid the amount of glucose obtained was equivalent to 99.3 per cent, 

 whereas with freshly prepared malt extract it was 82.7 per cent of maltose. 



A comparative study of the products of acid and enzymic hydrolysis was made by 

 Johnson (Jour. Chem. Soc. Trans., 1898, lxxiii, 490), who ascertained that the products 

 in the two cases differ to a marked degree. He states that when the products of diastatic 

 conversions are fractionated by means of alcohol, the precipitated portions have specific 

 rotations which may vary from about (a)D3-86 = +150 to about 190. These fractions are 

 reduced to represent the following peculiarities: They are unfermen table by Saaz yeast, 

 and theu' cupric-reducing powers and specific rotations can be expressed in terms of dextrin 

 and maltose. Dextrin has a specific rotation of (0)03-86 = +1^5, ^nd maltose (a)D3-86 = 

 -[- 135.4, so that no substance resulting from diastase hydrolysis can have a special rotation 



