130 DIFFERENTIATION AND SPECIFICITY OF STARCHES. 



of Brown and Morris, which has the formula {Cy2ii'2oOio):^+^2^' ^ specific rotatory 

 j)owcr of (0)0 = +183, and a reducing power, ft = 26.5 to 26.8. Tliese figures do not 

 agree v\ith those of Brown and Morris. 



Commercial amyloins were examined by Hiepe (The Country Brewer's Gazette, 1893 

 and 1894; Jour. Soc. Chem. Industry, 1894, xiii, 267) witli especial reference to their 

 fermentability, the percentages of dextrin and sugars, and the existence of the so-called 

 maltodextrin. After subjecting the amyloins to fractional precipitation by alcohol, they 

 found dextrin, maltose, isomaltose, and glucose, but no substance having the iiroperties 

 of maltodextrin. 



Dextrin-like products of starch were investigated by Biilow (Archiv f . ges. Physiologic, 

 1895, LXii, 131), who prepared baryta compounds of amylodextrin, erythrodextrin, and 

 aclii'oodextrin, and determined their specific rotatory and reducing powers. A number 

 of each of these compounds were studied. Various methods were pursued to obtain pure 

 achroodextrin, such as treatment with phenylhydrazine, heating in alkaline copper solu- 

 tion, precipitation with iron, fractional precipitation with barium hydroxide, and dialysis. 

 Quite a number of erythrodextrins, having different rotatory and reducing powers, are 

 recorded as having been obtained by these means. 



Meyer (Die Starkekorner, etc., loc. cit.) prepared by means of oxalic acid an erythro- 

 dextrin that had a rotatory power of (rt)D = +192°, and a reducing power R = 10. 



Lintner and Dull (Ber. d. d. chem. Gesellsch., 1895, xxviii, 1522) investigated the 

 products of the conversion by oxalic acid by the methods they had previously employed 

 in diastatic digestion. The chief difference noted was in the formation of dextrose as the 

 final product of the action of acid, while maltose was the final product of diastase. With 

 acid they obtained amylodextrin, erythrodextrin I, erytlirodextrin II a, erythrodextrin 

 II p, achroodextrin I, acliroodextrin II, isomaltose, and dextrose. With diastase they 

 recorded amylodextrin, erytlxrodextrin I, achroodextrin I, aclu'oodextrin II, isomaltose, 

 and maltose. The following were the color reactions of the dextrins with iodine : Erythro- 

 dextrin I, red- violet; erytlirodextrin II o, red-brown with dilute iodine solution, but blue 

 if the iodine is concentrated; erythrodextrin II /3, red-brown, even with concentrated 

 iodine; acliroodextrins, no color reaction. 



Ling and Baker (Proc. Chem. Soc. Trans., 1895, lxvii, 702, 739) obtained, by the 

 action of diastase, a substance wliich in its rotatory and reducing properties resembled 

 Brown and Morris's maltodextrin more closely than Lintner and Diill's aclii-oodextrin II. 

 They suggest that Lintner's isomaltose may consist of maltose and a simple dextrin, 

 C12H20O10+H2O. They isolated a substance having the optical and reducing properties 

 of "isomaltose," wliich fermented slowly with beer yeast, leaA^ng a residue which was 

 not altered by diastase. Tliis residue they state is a simple dextrin. 



Ost (Chem. Zeit., 1895, xix, 1501), in following Lintner and Diill's methods, found 

 that a mixture of maltose and dextrin had properties corresponding to Lintner's iso- 

 maltose, and he therefore concludes that Lintner's isomaltose is an impure maltose. Ost 

 believes it uncertain w'hether Lintner and Diill's erythrodextrin and achroodextrin are 

 homogeneous substances; and he calls attention to the fact that the specific rotatory 

 power of the so-called maltodextrin and achroodextrin II are not the same according to 

 different observers, and he states that Brown and Morris's non-reducing dextrin does 

 not exist. Ost believes that the dextrinous substance obtained by Zulkowsld (page 108) 

 is not a true dextrin, and he supports the statement of ISIuscuIus and Meyer, but in 

 opposition to Rohmann and Schifferer, that erytlu-odextrins are mixtures of achroo- 

 dextrin and starch. 



Prior (Bayerisches Brauer Jour., 1896, vi, 385) found in experiments with diastase 

 3 dextrins and maltose; and in some experiments with yeast also dextrose. He believes 

 Lintner's isomaltose to be a mixture of achroodextrin and maltose. 



