Starch acetolysis

Definite proof that the interchain linkage is 6 —> 1-a-D has been obtained by Wolfrom and coworkers,91 who have isolated crystalline /3-isomaltose [6-0-(/3-D-glucopyranosyl)-D-glucose] octaacetate (in 1 % yield) from the mild acetolysis of waxy maize starch and have presented evidence that... 

It should be borne in mind in these cases that while mixed acetic anhydride and sulfuric acid produce acetylation, they also bring about acetolysis which may result in severe depolymerization of the starch molecules. The occurrence of degradation is evident from the fact that the resulting acetates have acetyl values in excess of the theoretical value of 44.78%, and from the finding of glucose pentaacetate among the reaction products whenever low temperatures or low sulfuric acid concentrations are not employed. 

During acetolysis, the Schardinger dextrins were also shown to be more nearly similar to starch than to compounds of the levoglucosan type (see Fig. 8). 

Numerous studies by Karrer showed that acetolysis of Schardinger dextrins gave essentially the same yield of maltose as starch or maltose itself gave, when treated similarly. This type of observation was considered by Karrer to be strong evidence against the trisaccharide character of d-dextrin ( /3-triamylose ). 

Alkylated starch can be fragmented by acetolysis into water soluble tri- and tetra-saccharides.742 Formic acid, together with a small amount of acetyl chloride, may be used instead.743 Alkyl a-D-glucosides can be prepared by treating starch with hydrogen chloride a solution of hydrochloride in a simple alcohol.744... 

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