ERYTHRODEXTRtN, ACHROODEXTRIN, GRENZDEXTRIN, ETC. 129 



together with some soluble starch. He states that mixtures of this body and soluble starch 

 give iodine reactions ransinp; from a reddish-blue to a bluish-red, and that the so-called 

 erytlirodcxtrin is not an individual, but a mixture of porphj'rodextrin and soluble starch. 



Schifferer (Inaug. Diss., Kiel, 1S92) unsuccessfully attempted the preparation of the 

 so-called maltodextrins of Brown and Morris, but in no case did he succeed in obtaining 

 any substance that had anj' resemblance to the amyloins of these authors (page 115); 

 but he obtained dextrins, isomaltose, and maltose. Dextrins, he records, are not ferment- 

 able, but they reduce Fehling's solution, and he believes that their number is not more 

 than 2, and probably only 1 (achroodextrin), which does not give a color reaction with 

 iodine. He thinks that other dextrins are mixtures of this with varying proportions of 

 soluble starch, but his experiments failed to conclusively demonstrate this point. Rohmann 

 had found that such mbctures always give a blue reaction, and therefore that erythrodextrin 

 could not be made up of such a mixture (see above). 



Lintner and Diill (Ber. d. d. chem. Gesellsch., 1893, xxvi, 25-33) prepared amylo- 

 dextrin, erythrodextrin, achroodextrin, isomaltose, and maltose. They hold that the theory 

 of Brown and JMorris of the breaking down of amylin groups is untenable, and they con- 

 tend that the process is serial, amylodextrin being the first product, this being split into 

 erytlu"odextrin, this in turn into achroodextrin, and this into isomaltose, and this finally 

 into maltose. Amylodextrin (Ci2H2oOio)54 is precipitated, they found, by alcohol in the 

 form of a wliite powder, and that it can be obtained from a 20 to 30 per cent aqueous 

 solution in the form of spherocrystals. It is easily soluble in hot water. Even a 10 per 

 cent solution does not reduce Fehling's solution. Iodine gives with it a blue reaction. 

 Its rotatory power is (a)D = +196. Amylodextrin, they state, is broken up into 3 mole- 

 cules of erythrodextrin (CioH2oOio)54+3H20 = 3(Ci2H2oOio)i7.(Ci2H220ii). This is 

 easily soluble in water, and hardly soluble in hot 50 per cent alcohol. It separates from a 

 hot solution in dilute alcohol in the form of spherocrystals. It reduces Fehling's solution, 

 and gives a reddish-brown reaction with iodine. The rotatory power is given as 

 (a)D = +196. Erythrodextrin is in turn broken down into 3 molecules of achroodextrin 

 (3(Ci2HooOio)i7.Ci2H220n)+6H20 = (Ci2H2oOio)5.Ci2H220ii). It is easily soluble in 

 water, and almost insoluble in 70 per cent alcohol. Spherocrystals may also be obtained. 

 Fehling's solution is reduced, R = 10. No color reaction occurs with iodine. The rotatory 

 power is (0)0 = +192. It has a sliglitly sweetish taste. Achroodextrin is broken down 

 into isomaltose according to the following reaction : 9[(Ci2H2oOio)5.Ci2H220n)] -I-45H2O = 

 54 Ci2H220n- It was not obtained in spherocrystals. It is readily soluble in water, and 

 soluble in SO per cent alcohol and methyl alcohol, but insoluble in 95 per cent hot alcohol. 

 The latter will dissolve 5 per cent of maltose. It tastes sweet. Concentrated solutions 

 heated in water-bath turn yellow. Its rotatory power is (0)0 = +140, and its reducing 

 power, R = 80. It ferments with yeast and malt with difficulty, and is convertible into 

 maltose. The melting-point of its osazone is 150 to 153. 



The four stages of decomposition, Lintner and Dlill hold, go on simultaneously, the 

 energy of the diastatic process decreasing so that at a definite stage of the reactions, even 

 at favorable temperatures, i.e., when two-tliirds of the achroodextrin has been converted 

 into maltose, no more maltose is produced. They believe that the stoppage of the conver- 

 sion of dextrin into sugar at a temperature of 70 is owing to the formation of a modified 

 form of achroodextrin that withstands diastatic action. This has, however, been explained 

 by Pottevin, Effront, and others by a modification of the properties of the enzyme 

 when heated to this temperature. They hold that the amyloins, or maltodextrins, of 

 Brown and Morris, etc., are merely mixtures of dextrin and isomaltose, and sometimes 

 really identical with the latter, and that dextrins as well as starch are composed of 

 isomaltose groups. In a later contribution (Zeitschr. f. Brau., 1894, xvii, 339) they 

 describe a form of achroodextrin (achroodextrin II) which is similar to the maltodextrin 



9 



