Effects of natural chelating agents on the solubility of some physiologically important mineral elements in oat bran and oat flakes

Abstract

The solubility of mineral elements from oat bran and flake samples was studied by a method using equilibrium dialysis after enzymatic digestion of starch and proteins. The effects of six potential chelating agents common in food were tested on the solubility of mineral elements. The minerals studied were calcium, magnesium, iron, manganese, zinc and potassium, and the chelating agents were citric, lactic, malic, and ascorbic acids, glucose and xylitol. The mineral elements were tightly bound to the dietary fiber of the samples. Bran fiber bound even the zinc and calcium contributed through the enzymes used. Adding citric, malic, or lactic acids increased the solubility of the mineral elements studied, except for potassium which was easily dialyzable as such. Iron was insoluble in all situations. Citric acid was the most efficient chelating agent in solubilizing the mineral elements. The effect of malic and lactic acids on the solubility of minerals was small. No effect was found with glucose, ascorbic acid, and xylitol. Thus, the intestinal availability of mineral elements may be affected by dietary hydroxy acids such as citric and malic acids in high dietary fiber diets.