116 DIFFERENTIATION AND SPECIFICITY OF STARCHES. 



it splits into dextrin and maltose, while maltodextrin dialyzes intact. They give malto- 



dextrin the formula ] ,^'^„"'/-w'\ • I" their article published in 1889, they point out the close 



resemblance between the amylodextrin of Nageli and the maltodextrin described in their 

 earlier contributions, and they state that this substance is neither identical with soluble 

 starch, as held by some; nor is it identical with the starch-cellulose of C. NageU, as held 

 by Meyer; nor is it a mixture of dextrin and maltose, as held by Herzberg. They also 

 assert that while the composition of amylodextrin can be expressed in terms of a mixture 

 of starch and dextrin, it is really a well-defined chemical substance; that it does not possess 

 the optical properties ascribed to it by its discoverer; that in composition it is analogous 



,^'"„""„", , and constituted 



by one aimjloin or maltose group with six amylin or dextrin groups; that amylodextrin, 

 like maltodextrin, is hydrolyzed immechately into maltose; that it is an entirely different 

 substance from soluble starch, with which it has been confounded ; and that the first action 

 of dilute acid on ungelatinized starch in the cold is to convert the starch-substance into 

 soluble starch, wliich is gradually hydrolyzed into amylodextrin, a portion going at the same 

 time into solution and being changed into dextrose; and that there is a great similarity 

 between amylodextrin and inulin. The formula} and molecular weights they give as follows : 



A '1 d -t ■ S^^12H220ii) _ M It d t ' i ^*-'12H220ii) _ < (C12H22O11) 



( (Ci2H2oOio)6' ' (Cl2H2oOio)2 ( (Ci2H2oOio)4 



IMol. weight 22S6 Mol. weight 990 Mol. weight 19S0 



The purified amylodextrin had the following specific rotatory and reducing coefficients, 

 (a)j3.86 = 206.11, and k 3.86 = 9.08, respectively. 



A further study of the maltodextrins ("amyloins") was made by Morris and Wells 

 (Trans. Inst. Brewing, 1892, v, 133) by means of analyses of fermenting yeasts at 

 different stages of fermentation. They found, in experiments with Frohberry and Saaz 

 yeasts, that the properties of these yeasts so differ that one may be used to determine 

 free maltose and the other to determine the fermentable maltodextrin. The Saaz yeast, 

 it was found, does not ferment maltodextrins, but the Frohberry 3'east does. 



Schifferer (Neue Zeit. Rub. Zuck. Ind., 1892, xxix, 167; Inaug. Diss., Kiel, 1892) 

 endeavored to prepare the maltodextrins of Herzfeld and of Brown and Morris, but without 

 success, and in no case was he able to separate a body which resembled in any way the 

 so-called amyloins (maltodextrins) referred to by the latter. He regards Herzfeld's malto- 

 dextrin as being probably a mixture of 26 per cent of dextrin and 74 per cent of isomaltose; 

 and the maltodextrin of Brown and Morris as a mixture of 67 per cent of dextrin and 

 33 per cent of isomaltose. 



The amylodextrin (reaUy soluble starch) separated by Lintner and Diill (Ber. d. d. 

 chem. Gesellsch., 1893, xxvi, 2533) was obtained by stopping the action of diastase 

 while the preparation still gave a blue reaction with iodine, and precipitating with hot 

 40 per cent alcohol. The precipitate thrown down during coohng was purified by repeated 

 fractionation with 40 and 30 per cent alcohol, yielding an extremely light white powder 

 that was slightly soluble in cold water, but ^•ery soluble in hot water. It ga^•e a deep- 

 blue reaction with iodine, and its specific rotatory power was (0)0 = 196, and its formula 

 (Ci2H2()Oio)54. From a 20 to 30 per cent solution they obtained spherocrystals. 



The products of starch transformation by the actions of several kinds of yeast were 

 studied by Hiepe (Country Brewer's Gazette, 1893 and 1894; Jour. Soc. Chem. Ind., 

 1894, XIII, 267), but he failed to find any homogeneous precipitate having the properties 

 of a body between dextrin and isomaltose, and he states his belief that the intermediate 

 products between dextrin and sugar (the amj-loins of Brown and Morris) consist of a 

 mixture of dextrin, isomaltose, maltose, and glucose. 



