ERYTHRODEXTRIN, ACHROODEXTRIN, GRENZDEXTRIN, ETC. 121 



Two years later, Payen (Ann. de cliini. et phys., 1836, lxi, 355 and lxv, 225) reported 

 that the rotatory power of dextrin was equal to that of starch; that all starches have the 

 same elementary composition (CgHio0.5) ; that all parts of the same grain,including dextrin, 

 have the same elementary composition; and that the dextrins formed by dilute acid, 

 diastase, and torrefaction are merely physical modifications of the same substance. 



Fiirstenberg (Ann. d. Chem. u. Pharm., 1844, lii, 417) dicovered that starches of 

 cereals contain dextrin similar to that obtained by the action of dilute acid, or by diastase 

 on starch, and that it is without reducing action on copper solutions. Blondeau de Carolles 

 (.Jour. f. prakt. Chemie, 1844, 33, 439), Fehling (Ann. d. Chem. u. Pharm., 1845, lv, 13), and 

 Kalinowsky (Jour. f. prakt. Chemie, 1845, xxxv, 193) found that by the action of sulphuric 

 acid a number of compounds are formed, according to the time of action and strength of acid. 

 Bechamp (Compt. rend., 185G, xlii, 1210) noted that a substance (erythrodextrin) may be 

 formed that is intermediate between starch and dextrin (achroodextrin), giving a reddish 

 coloration with iodine, and which he regards as an inversion product of starch. 



The assertion of Payen that the dextrins formed by the action of dilute acid, diastase, 

 and torrefaction, respectively, are merely physical modifications of the same substance 

 was strongly opposed by Mulder (Chemie des Bieres, Leipzig, 1858, 166), who asserts that 

 they differ from one another in their reactions, especially with precipitants. 



In 1860, Musculus (Compt. rend., 1860, l, 785) refers to a gummy body formed by 

 the action of diastase or acid wliich does not give a color reaction with iodine, which he 

 did not isolate, but records as dextrin. He believed that the sugar formed during digestion 

 is dextrose; that the sugar is not formed from dextrin, as was at that time and for many 

 years believed, but that dextrin and sugar are formed coincidently from starch by the 

 action of water, the proportion being 2 of dextrin to 1 of sugar. The following year he 

 reasserted the proportion of dextrin to sugar, and also noted that this ratio exists as soon 

 as the blue reaction with iodine ceases. He believed that the sugar prevents further change 

 in the dextrin, but that at the same time it does not prevent the breaking down of starch. 

 In a later article, JVIusculus (Ann. de chim. et phys., 1865, vi, 177) studied the character- 

 istics of what he refers to as a "true dextrin," which is a body (achroodextrin) that does 

 not give a color reaction with iodine, does not reduce copper solutions, and is not digested by 

 diastase. In further studies (Compt. rend., 1869, lxviii, 267) Musculus gives a ratio of 1 : 1 

 and states that during the transition of starch by diastase and acid to "colorless dextrin" 

 (non-color reacting dextrin) there is produced a modification, which he calls "insoluble 

 dextrin," which is insoluble in cold water, which gives a violet to a wine-red brown or yellow 

 reaction with iodine, is saccharified by diastase, and yields by acid less sugar than starch. 



The assertion of Musculus that the colorless dextrin is not digested by diastase was 

 opposed by Payen (Ann. de chim. et phys., 1866, vii, 382), who to the contrary found it 

 to be readily sacchai'ified. Nasse (Demateriis amtlaceis num in mammalium inveniantur 

 disquisitio. Diss. Halle, 1866) reported a body under the name of " dextrinogen " which 

 corresponds with the so-called colorless dextrin of Musculus. 



Three stages must be recognized, writes Griessmayer (Ann. d. Chem. u. Pharm., 

 1871, CLX, 40), in the process by which starch wliich has been boiled and set aside is finally 

 transformed into glucose and other products: (1) After a few days the addition of a small 

 amount of weak iodine gives a violet reaction, never a blue. The red of the iodine-dextrin 

 reaction combining with the blue of the iodine-starch reaction makes violet. (2) After 

 standing about 8 days the addition of iodine gives a red reaction, which is attributed to a 

 substance he names dextrin I. By carefully adding a moderately concentrated solution 

 of tannic acid, this dextrin can be precipitated, leaving the starch. Besides dextrin I, 

 there is another dextrin present which does not give a color reaction with iodine. (3) 

 After starch has stood for more than 8 days there occurs a time when the addition of iodine 

 causes a red coloration which disappears izmnediately, but testing with Fehhng's solution 



