Cereal Chem 62:218-222   |  VIEW ARTICLE
Solubility Behaviors of the Minerals, Proteins, and Phytic Acid in Rice Bran with Time, Temperature, and pH.

E. T. Champagne, R. M. Rao, J. A. Liuzzo, J. W. Robinson, R. J. Gale, and F. Miller. Copyright 1985 by the American Association of Cereal Chemists, Inc. 

Solubility data are presented as a function of time, temperature, and pH for eight elements in rice bran: iron, zinc, copper, potassium, magnesium, calcium, nitrogen, and phosphorus. The greatest increase in solubilization of the endogenous minerals and proteins with time of incubation was during the first 30-40 min at 20 and 60 C, with copper and phosphorus being exceptions. With the exception of endogenous zinc, increasing the temperature from 20 to 60 C resulted in increased solubilization. Endogenous zinc was found to be less soluble at 60 than at 20 C at times greater than 60 min. Solubility profiles of phosphorus and nitrogen components as a function of pH did not correspond, except in the pH 1-2 range, which shows that association between protein and phytic acid occurred only in this range. Potassium, magnesium, and calcium solubilities as a function of pH corresponded to those of the phytic acid salts of these minerals. A possible association of copper and zinc with the proteins in the pH 6.8-10.3 and 6.2-10.3 ranges, respectively, was indicated by the behavior of their solubility curves.