Preparing method of alginic acid which is bonded a high concentration of magnesium ion, calcium ion or iron ion

摘要

PURPOSE: A method for preparing alginic acid combined with a magnesium ion, a calcium ion or an iron ion (Fe2+) in high concentration is provided, to remove the inherent unpleasant odor of alginic acid and to enable the physiological activity of alginic acid to be maintained. CONSTITUTION: The method comprises the steps of heating a mixture of purified water and the pulverized brown algae to a temperature of 90-100 deg.C, adding Na2CO3 to the solution and maintaining the heated state for 30 min to 10 hours; lowering the temperature to 50-70 deg.C, and filtering it to remove the pulverized brown algae; and adding any one selected from the group consisting of a magnesium salt, a calcium salt, an iron salt, Mg-EDTA, Ca-EDTA and Fe-EDTA to the remaining filtrate, to supersaturate magnesium, calcium or iron, heating the solution to 100-150 deg.C, and maintaining the temperature for 30 min to 10 hours. Optionally a water-soluble chitosan with an average weight molecular weight of about 600,000 is added to the obtained final product. Preferably the brown algae are kelp; the magnesium salt is MgCO3 or MgCl2; and the calcium salt is CaCO3 or CaCl2.