The effect of phytic acid and some natural chelating agents on the solubility of mineral elements in oat bran

The effect of phytic acid on the solubility of mineral elements in oat bran was studied by digesting phytic acid with phytase enzyme. The combined effect of phytase treatment and the addition of three chelating agents common in food were also tested. Starch and proteins were digested enzymatically. The sample was dialysed, using an equilibrium dialysis method, and the soluble mineral elements were analysed from the dialyzate. The minerals studied were calcium, magnesium, iron, manganese, zinc, potassium and phosphorus. The chelating agents used were citric and malic acids and glucose. The phytase treatment increased the solubility of minerals less than expected. Citric acid was the most efficient chelating agent. The effect of malic acid was small. The results confirmed that the minerals were tightly bound to the dietary fibre of oat bran and were only partially released when the influence of phytic acid was reduced by degradation. (C) 2002 Elsevier Science Ltd. All rights reserved.