Effects of pH, Iron and Metal Concentration on Aluminium Coordination

Abstract

We have investigated the likelihood of aluminium (Al) being excreted in based on its binding capacity with dietary fiber (DF). The results of our previous study revealed that DF extracted from highly viscous food items such as aloe, okra, moroheiya, and wakame has strong metal binding capacity. Therefore, in the present study, the effects of pH, the presence of iron (Fe[II, III]) and metal (Al and Fe) concentrations on the binding capacity of Al to DF were examined. In both insoluble and soluble fractions extracted from these food items, the amount of Fe binding was higher than that of Al, except for the IDF fraction from hijiki. Furthermore, it was confirmed that, in the presence of both Al and Fe, Fe had higher affinity to alginic acid in gel filtration. For a decrease in pH from 3.5 to 2.0, the levels of both Al and Fe binding to alginic acid were reduced, with a greater degree of reduction observed for Al. For incremental increases in the concentrations of Al and Fe together, the level of Al binding to alginic acid was slightly increased only at pH 2.7±0.3.