152 DIFFERENTIATION AND SPECIFICITY OP STARCHES. 



of less than 135.4°. When, however, fractions from the products of acid hydrolysis are 

 separated the specific rotations vary between about (a) D= +190° and (0)0= +80°. These 

 fractions contain no free glucose, because they are unfernientable by Saaz yeast; moreover, 

 they can not be molecular aggregates of maltose and dextrin, since the specific rotation 

 of a maltodextrin can not fall much below (0)0 = + 150°, and we are in the presence here of 

 fractions whose rotations can fall as low as 80°. There are therefore present in acid reactions 

 intermediate substances which do not exist in diastase conversions. In the results of fer- 

 mentation and dialysis tests he gives evidence to show that the fractions are definite 

 compounds and not mixtures of glucose and other carbohydrates. Further proof that 

 the intermediate products of acid and diastatic hydrolysis are not identical is shown 

 by the difference in their behavior to diastase and acids. Soxlilet had already reported 

 that diastase has no action on the dextrins produced by acid, but Johnson shows that 

 it has a slight action, which he explains by the assumption that it may attack mole- 

 cules of starch that have not been acted upon by acid, although he admits that it 

 attacks conversions wliich do not give a blue reaction with iodine. Diastase has no 

 action on fractions having rotations of 114° and lower, but such dextrins do not offer 

 much resistance to acids. 



In studies of the oxidation products and constitution of maltodextrin. Brown and 

 Millar (Proc. Chem. Soc, 1899, xv, 11) found that this substance is completely hydrolyzed 

 by diastase into maltose, and by acids into c?-glucose. When maltodextrin is oxidized 

 with mercuric oxide and barium hych'oxide, the greater part of the product appears as a 

 barium salt of a complex carboxylic acid, which they provisionally term maltodexlrinic 

 acid A. When maltodextrinic acid A is subjected to diastase it yields 40 per cent of maltose 

 and 60 per cent of maltodextrinic acid B. When acted upon by dilute oxalic acid, malto- 

 dextrinic acid A yields 85.8 per cent of d-glucose and a simpler form of maltodextrinic acid. 



Van Laer (Jour. Fed. Inst. Brewing, 1900, vi, 162) notes that the differences in the 

 products of acid and diastase are of importance in brewing. He states that acid hydrolysis 

 differs from enzymic hydi'olysis not only in that the end-product of the former is glucose 

 and that of the latter maltose, but also in that the intermediate products differ. In order 

 to meet certain conditions favorable to brewing he proposes to partially saccharify grits 

 by dilute acid, then neutralize, and finally complete saccharification by malt. 



In the saccharification of starch by acid it was found by Effront, as stated, that maltose 

 is formed, but Lintner and DiUl {loc. cit.) did not obtain maltose, and they look upon the 

 absence of maltose in acid hydrolysis as being the essential distinctive feature to differen- 

 tiate the products of acid and enzymic hych-olysis. Rolfe and Defren {loc. cit.) found mal- 

 tose present in both acid . and enzymic hydrolysis. Rolfe and Haddock (Jour. Amer. 

 Chem. Soc, 1903, xxii, 1015) and Rolfe and Geromanos {ihid., 1003) support Rolfe and 

 Defren. Rolfe, in a large number of determinations of the products of acid hyth'olysis 

 of corn starch and potato starch, found conclusive evidence of the production of a reducing 

 body other than dextrose, and Rolfe and Haddock made alcoholic fractions of a conmiercial 

 glucose that had been made by the action of hych-ochloric acid at a pressure of 2 atmos- 

 pheres, and having a specific rotation of 126.5° and a reducing power of 0.575. From these 

 fractions they prepared crystals of maltosazone and dextrosazone. 



Dierssen (Zeit. angew. Chem., 1903, xvi, 122; Jom-. Soc. Chem. Ind., 1903, xxii, 312) 

 used oxalic acid, and he agrees with Lintner and Diill in regard to the absence of maltose. 

 Dierssen concluded that in acid hydrolysis glucose, lo\'ulose, and a disaccharid are formed. 

 The rotatory and reducing powers of the latter, and the solubility, appearance, and melting- 

 point of its osazone correspond with Lintner's isomaltose, but it is not affected by diastase, 

 while Lintner's isomaltose (which was prepared by diastase) was converted by this enzyme 

 into maltose. Wliether or not the isomaltose obtained by Lintner by acid hj'drolysis 

 would have been converted by diastase was not noted. He states that it can not be ideuti- 



