124 DIFFERENTIATION AND SPECIFICITY OF STARCHES. 



the results of these investigators as far as reaction No. 8 is concerned, namely, that at 

 60 or 63, or even below, gelatinized starch undergoes a definite process of hydration 

 which results in the production of practically 80 per cent maltose and 20 per cent dextrin. 

 He states, however, that he did not succeed in obtaining trustworthy evidence of definite 

 reactions representing the other numbers, nor sufficiently concordant results to warrant 

 the assumption that at any given temperature the reaction can always be represented by 

 definite formulae. The production of maltose he found to be continuous, and not by steps, 

 and that there was never a complete disappearance of dextrin. Squire quotes Southy 

 (Brewing, etc., London, 1877) as having noted that at lower temperatures the proportion 

 of dextrin to sugar is increased. 



Almost coincidently with the appearance of Brown and Heron's article, O'Sullivan 

 (Proc. Chem. Soc. Trans., 1879, xli, 770) reported that he had modified his views regarding 

 the number of dextrins, he having now reached the conclusion that there are formed 1 

 erythrodextrin and 3 achroodextrins. He states that he separated them in a nearly pure 

 state by means of precipitation with alcohol, and he designates them as follows : a-dextrin 

 colored brownish-red with iodine; (3-dextrin I, /3-dextrin II, and /3-dextrin III, none of 

 which gives a color reaction with iodine. O'Sullivan beUeved that the formation of 

 dextrins is not due to the breaking down of the starch-molecule into simpler bodies, but 

 to a rearrangement of the molecules, so that there are formed a series of substances of 

 the same molecular weight, but differing in their behavior, owing to the change in con- 

 stitution. He thought, therefore, that the entire starch-molecule is affected at once, in 

 contradistinction to the serial degradation according to the theories of Musculus and 

 Gruber and of Brown and Heron. 



Still another theory of the processes of saccharification was offered at this time by 

 Herzfeld (Ueber Maltodextrin, Dissertation, Halle, 1879), according to which the trans- 

 formation of the starch by diastase is by serial actions, giving rise consecutively to amylo- 

 dextrin, erythrodextrin, and achroodextrin, the latter being split into maltodextrin and 

 maltose. Below 65 it is stated that achroodextrin and maltose are formed, but at 

 higher temperatures also erythrodextrin and maltodextrin. 



A process for the manufacture of dextrin was devised by Lauga (Jour. Soc. Chem. 

 Industry, 1882, i, 513), which consists essentially of boihng glucose juice with concentrated 

 phosphoric acid until dextrinization, at which time the preparation is cooled to about 50, 

 neutralized, and filtered under pressure through animal charcoal, etc. 



The products of the conversion of starch by organic and inorganic acids were examined 

 by Salomon (Jour. f. prakt. Chemie, 1883, xxviii, 82), who concluded, contrary to other 

 investigators at this time, that only one kind of dextrin results in the saccharification of 

 starch. He took some very pure dextrin that was obtained from a solution from which 

 starch had been removed. The solution of this dextrin gave a brownish-red reaction with 

 iodine and, after purification by resolution in water and precipitation by alcohol, it gave 

 a brownish reaction that disappeared immediately, and it failed to reduce Fehling's solu- 

 tion. He also held that only dextrin and glucose are produced, no maltose. 



Schulze (Jour. f. prakt. Chemie, 1883, xxviii, 311) studied the influence of acetic 

 acid on starch by treating starch with 20 per cent acid under pressure, and obtained, as 

 he states, a dextrin like the a-dextrin of Bondonneau. Heating for 4 hours gave rise almost 

 exclusively to this dextrin, but further heating caused the formation of more or less glucose. 



In 1885, Brown and Morris (Ann. d. Chem. u. Pharm., 1885, xxiii, 72; Jour. Chem. 

 Soc, 1885, XLVii, 527) published what they state is to be looked upon as a continuation 

 of the paper by Brown and Heron that appeared in 1879 (page 123). By this extended 

 work they were enabled to add certain facts tending, as they believe, to a better knowledge 

 of the products of the diastatic digestion of starch. The chief results of their investigation 

 may be summarized as follows: 



