H-D-T Isotope Exchange and Labeled Starches

Labeling starch with the 14C isotope of carbon at the anomeric position of the reducing terminal D-glucose unit was achieved by treatment with labeled cyanide followed by alkaline hydrolysis of the resulting cyanohydrin.17 Labeled maltose could be prepared from such labeled starch.18 In addition, starches modified by substitution might be labeled in the substituent being introduced, as shown by Kratz and Kaufmann,19 who prepared starch acetylsalicylate with 14C in the acetylsalicylate moiety. 

The behavior of starch with base depends first of all on the type of base, its concentration, and on either the presence or absence of oxygen, as well as on the temperature and time of the reaction. Earlier reports20 used the term hydrolysis to describe the reaction of starch with bases as well as with various acids and hydrolyzing salts, but the term degradation is more appropriate to describe the reaction of starch under basic conditions.21 

Starch derivatives may also undergo hydrolysis and degradation under alkaline conditions. The hydrolysis of the nitriles, amides, and esters resulting from the reaction of starch with corresponding vinyl monomers is obvious. Considerable attention has been paid to the alkaline degradation of starch dialdehyde. It de-polymerized readily supposedly as a result of -elimination at C-5, although such a questionable -elimination should not be facile).70 

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