Cereal Chem 39:318 - 326.  |  VIEW ARTICLE

Structure of the Starch Granule. III. Solubilities of Granular Starches in Dimethyl Sulfoxide.

H. W. Leach and T. J. Schoch. Copyright 1962 by the American Association of Cereal Chemists, Inc. 

Granular starches dissolve without swelling in cold anhydrous diethyl sulfoxide. Various starch species show different rates of solution, reacting differences in molecular bonding within the granules. Corn and sorghum starches and their waxy counterparts undergo rapid fragmentation and dissolution in this solvent, suggesting a porous or heterogeneous structure. Arrowroot and potato starches dissolve much more slowly without granule fragmentation, indicating a more homogeneous and impermeable structure. These results agree with previously reported digestibilities of granular starches by alpha-amylases. Solubilization is decreased by chemical cross-bonding, and increased by hydroxyethylation. In contrast, aqueous dimethyl sulfoxide (80-95%) dissolves corn and potato starches completely and much more rapidly. Viscometric studies show no molecular degradation of corn starch solutions in 90% dimethyl sulfoxide on prolonged standing, but potato starch undergoes a slow breakdown.