Cereal Chem 59:538 - 542.  |  VIEW ARTICLE
In Vitro Interaction of Rice Hemicellulose with Trace Minerals and Their Release by Digestive Enzymes.

R. R. Mod, R. L. Ory, N. M. Morris, and F. L. Normand. Copyright 1982 by the American Association of Cereal Chemists, Inc. 

In vitro binding of calcium, magnesium, and manganese by water- and alkali-soluble hemicelluloses and hemicellulose molecular weight fractions above 100,000 were determined after incubation at 37 C for 1/2, 1, and 2 hr. Binding was complete within 30 min in the model system. Effects of digestive enzymes (hemicellulase, pepsin, and trypsin) and pH on minerals bound to hemicelluloses were examined in 16-hr incubation tests. Both enzymes and changes in pH released considerable amounts of bound minerals to different degrees, suggesting that such released minerals should be available for resorption in vivo. Data on calcium and magnesium in combination for binding studies with water-soluble hemicelluloses showed that both are bound to the hemicellulose in essentially the same amounts, indicating that neither should interfere with the other for absorption and/or binding by hemicellulose in vivo. However, calcium and magnesium used in combination for binding studies with alkali-soluble hemicellulose indicated that calcium intake may affect dietary magnesium binding and release by this class of hemicellulose.