Cereal Chem 54:266 - 271.  |  VIEW ARTICLE
Calcium Binding by Hydroxypropyl Distarch Phosphate and Unmodified Starches.

L. F. Hood and G. K. O'Shea. Copyright 1977 by the American Association of Cereal Chemists, Inc. 

Hydroxypropyl distarch phosphate (HDP) and unmodified starch were held in calcium solutions. The starch was separated centrifugally and the amount of calcium remaining in the supernatant was determined by atomic absorption spectrophotometry. Bound calcium was calculated by subtracting the calcium in the supernant from the calcium in the original solution. The effecxts of starch gelatinization, pH, temperature, time, and calcium:starch ratio on binding were studied. Ungelatinized, unmodified starch and HDP bound up to 86 microgram calcium/g starch. Binding was influenced markedly by the calcium concentration in the reaction mixture. The Ph influenced the degree of binding by HDP, but had no effect on unmodified starch. As the temperature increased from 5 to 45 C, the extent of binding decreased. The amount of calcium bound was constant after a 20-min reacion time. Unmodified tapioca bound more calcium than unmodified corn or waxy maize starch. Gelatinization of both HDP and unmodified tapioca starch nearly eliminated binding. These results suggest that binding of calcium by starch is related to granule structure and that it is principally nonionic in unmodified starch, and both nonionic and ionic in HDP.