Preparation method of dextran iron

The invention discloses a preparation method of dextran iron, which comprises the following steps: preparing low-molecular-weight dextran by adopting heat-resistant dextran sucrase single enzyme, and oxidizing the dextran by adopting a hydrogen peroxide solution as an oxidizing agent to obtain oxidized dextran; ferric glucan is prepared by titration and complexation of a potassium hydroxide solution and a ferric trichloride solution, and is cured under the conditions of normal temperature and normal pressure to obtain the ferric glucan; and filtering by adopting nano ultrafiltration membranes with different molecular weights to remove unreacted dextran, micromolecular dextran iron and ions in the dextran iron so as to obtain purified dextran iron. The dextran iron prepared by the method is uniform in molecular weight distribution, high in stability, good in solubility and low in impurity content, and the preparation process is energy-saving and environment-friendly. 本发明公开了一种葡聚糖铁的制备方法，采用耐热葡聚糖蔗糖酶单酶制备低分子量的葡聚糖，随后