Revised look at the interaction of starch with electrolyte: effect of salts of metals from the first non-transition group

Anions usually have been shown to play a dominant role in the interactions between starches and electrolytes prepared from various salts of metals from the first non-transition group. Except for lithium, the salts, at least their cations, did not penetrate starch granules and retarded granule swelling. Because the lithium cation has specific colligative properties and coordination ability it is distinctly different from the other salts of this group and formed complexes with starch. However, it was not equivalent to the formation of starch lithium salt and hydrochloric acid. The results of this study explain the acidity of starch and all other phenomena thus far interpreted with the argument that salt cations formed metal salts of starch. Our arguments are collected from the studies, which involved dynamic rheometry, crossed polarized-non-polarized light beam microscopy (CLBM), powder X-ray diffraction, energy dispersion spectroscopy (EDS), F-19, Na-23, and Cl-35 NMR, AFM and SEM of sliced starch granules, and CD/ORD. Irreversibility of swelling of granules was shown by CLBM. (C) 2001 Elsevier Science Ltd. All rights reserved.