ERYTHRODEXTRIN, ACHROODEXTRIN, GRENZDEXTRIN, ETC. 



127 



the starch is mixed to a thick cream ^\ith cold water and then treated with 1 per cent of 

 its weiglit of siilpiiuric, hydrochloric, or nitric acid for 24 hours. The preparation is then 

 washed free from acid. This prepared starch is either dried or again mixetl with water 

 to a cream, and heated to 160° to 170° in an oil bath, or by means of superheated steam, 

 until all the starch is converted. The solution is then refined. 



The percentages of dextrin, maltose, starch, etc., in conmiercial dextrin were studied 

 by Hanofsky (Mittheil. d. k. k. Tech. Gew.-Museums, 1889, 56), the essential results being 

 given in table 9. 



Table 9. 



Contrary to the findings of a number of investigators mentioned in the preceding 

 pages, Flourens (Compt. rend., 1890, cx, 1204), from experiments on the products of the 

 saccharification of starch with acids, was led to the conclusion, from the entire agreement 

 of the rotatory and reducing powers at the various stages of the process, that only one 

 and not several dextrins are formed; and also glucose, but not maltose. 



In an article on the chemistry of starch and the nature of dextrins, Scheibler and Mit- 

 telmeier (Ber. d. d. chem. Gesellsch., 1890, xxiii, 3060), it is stated that dextrin could be 

 reacUly purified by repeated precipitation with alcohol, or by osmosis. The dextrin thus 

 obtained they look upon as a mixture of several dextrins. They prepared the hydrosazone 

 by dissolving the dextrin in the cold in the presence of phenylhydi-azine. The hydrosazone 

 is hych'olyzable by diastase, and is quite soluble in water. When a cold solution of dextrin 

 was treated with sodium amalgam a product can be precipitated by alcohol which does 

 not reduce Feliling's solution, nor dissolve in phenylhydrazine. This body, which appears 

 in the form of a white powder, they named dextrite. It is saccharified by diastase or strong 

 acids; it is not precipitated by basic acetate of lead or by lime-water; it does not reduce 

 Feliling's solution, but accjuires reducing power by treatment with diastase or dilute acid; 

 its solution reddens litmus; it decomposes calcium carbonate; and it is soluble in phenyl- 

 hydrazine. They call attention to the fact that a number of obser\'ers have made use of 

 oxidizing agents to destroy sugars in the preparation of dextrins upon the erroneous assump- 

 tion that the dextrin itself is not affected. The non-reducing dextrin obtained in this way 

 they believe is probably a carboxylic acid of dextrin. They also state, in support of some 

 observers and contrary to others, that pure dextrin reduces Fehling's solution. 



Leitner (Zeits. f. angew. Chem., 1890, 546) noted that permanganate brings about 

 a conversion of starch into gmnmy substances which he states differ from dextrins by 

 their acid reaction and by theu- yielding precipitates with basic lead acetate and barium 

 hydroxide. 



Glycerine has been employed to prepare soluble starch by restricting its action, and 

 by further action to convert the soluble starch into dextrins or dextrin-like bodies. Zul- 

 kowski (Ber. d. d. chem. Gesellsch., 1891, xxiii, 3295) subjected starch to hot glycerol, 

 and found that it was soon completely broken down into erytlirodextrin, achroodextrin, 

 and a number of bodies of increasing solubihty as the reaction proceeded. These various 

 substances were separated bj^ means of their different solubilities, but it was found difficult 

 to remove the last traces of glycerine. In a later investigation by Zulkowsky in associa- 

 tion with Franz (Ber. d. osterr. Gesellsch. z. Forderung chem. Ind., 1894, xvi, 120), 



