136 DIFFERENTIATION AND SPECIFICITY OP STARCHES. 



with Ling and Baker's a-maltodextrin, and with Lintner's achroodextrin II. Grenz- 

 dextrin II is hydrolyzed by malt extract into maltose and a compound named r-malto- 

 dextrin, wliich in turn may be broken down into maltose and dextrinose. 



From this and his previous investigations, Syniewski holds that the starch-molecule 

 consists of 4 amylogen groups, its formula being C216II300O1SO) each group consisting of 9 

 glucose groups united tlu'ough then- 9 cai'bonyl groups, thus proving that only monocarbonyl 

 groups exist among the glucose groups. The glucose groups, he conceives, are arranged 

 into 1 dextrin group consisting of 3 rings of glucose groups linked together, and 3 maltose 

 groups united to the dextrin group. The amylogen groups are conceived to be so combined 

 in the starch-molecule that each is united to three others through 6 carbinol linkages, 

 the carbinol linkage existing between the dextrin groups (d-carbinol linkage) as well as 

 between the maltose groups (?/i-carbinol Unkage) of the amylogen groups. Amylodextrin, 

 he states, is derived from the starch-molecule by the decomposition of 7?i-carbinol linkage 

 on the addition of 6 molecules of water. Heating starch-paste at 140° will not cause a 

 decomposition of starch, but such decomposition can be brought about, he found, by 

 diastase. Malt extract, by bursting the dextrin rmg at first, releases a carbonyl combina- 

 tion between the two glucose groups of each dextrin group, and then gradually all the 

 maltose groups are separated from the dextrin group, producing grenzdextrin I, which 

 was made up of dextrin groups imited tlu'ough d-carbinol linkages. The fm'ther action of 

 diastase, he Avrites, causes the separating of one maltose group from each dextrin group 

 of the grenzdextrin, finally resulting in maltose and its isomer dextrinose, in the molecule 

 of which the glucose groups are united by f/-carbinol bonds. Malt extract at 78° likewise 

 breaks the carbonyl bonds, primarily those which bring the glucose groups to the dextrin 

 ring, thus forming gTenzdextrin II, which is put down as being composed of 2 complexes 

 (Cis) united by ci-carbinol linkage consisting of 3 glucose groups linked together through 

 carbonyl bonds. It is concei^'able, he states, that the separation of a maltose residue from 

 this dextrin will produce ^-maltodextrin and that dextrinose results from the fm'ther split- 

 ting of the maltose gi'oup. Although the carbinol linkage seems to have great resistance 

 to the hydrolytic action of diastase, dextrinose nevertheless finally breaks up into 2 

 molecules of glucose. 



Another communication by Syniewski {ibid., page 109) reports the changes bi'ought 

 about in starch by subjection to the action of 40 per cent formaldehyde for 2 months. 

 He investigated especially the iodine combinations of amylodextrin and concluded that 

 each amylogen residue of the amylodextrin takes up 3 atoms of iodine, these atoms prob- 

 ably replacing the hytlroxyls of the primary alcohol group CH2(0H), each amylogen residue 

 containing 3 such hych'oxyls. That the hydroxyls of the primary and not the secondary 

 groups are replaced by the iodine is, he states, confirmed by barium compounds of amylogen, 

 in which undoubtedly the primary hydi'oxyls are replaced by barium, the barium compound 

 not combining with iodine, inasmuch as it shows no iodine reaction. This conception 

 of the composition of iodine-amylodextrin lends probably, Syniewski holds, to the theory 

 that the same alcohol groups of the amylogen residues also take part in the reaction with 

 formaldehyde, the prmiary alcohol groups evidently being replaced by formaldehyde 

 groups in the compound of amylodextrin and formaldehyde. By the hydrolytic action 

 of added water, or by the addition of acids, one hydi'oxyl group after another will be set 

 free, giving rise to color manifestations induced by the addition of iodine. This change of 

 color in the iodine reaction, which occurs also in the diastatic hydrolysis of starch, is due, 

 he holds, to the gradual breaking away of the dextrin molecules from the maltose group, 

 containing primary alcohol groups. It is therefore probable that the dextrins I and II, 

 described in 1899, would show a red or brown color with iodine. 



In experimental studies of the processes concerned in the conversion of starch into 

 sugar, Moreau (Ann. d. d. Soc. roy. d. Sc. med. e. nat. d. Bruxelles, 1903, xii, 117; Jahr. 



