Characterization and digestion features of a novel polysaccharide-Fe(III) complex as an iron supplement

Using a sulfated polysaccharide from the gonad of pacific abalone (AGSP), a novel polysaccharide-Fe(III) complex, AGSP-Fe(III), was synthesized, and it was characterized by a series of methods including ultraviolet-visible (UV-vis) spectroscopy, Fourier transform-infrared (FT-IR) spectroscopy, circular dichroism (CD) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results showed that AGSP-Fe(III) was formed by the Fe-O bond between sulfate, carboxyl, and hydroxyl groups in AGSP and Fe, its particle size reached a maximum of 200 nm after aggregating, and its surface morphology presented relatively regular columnar or spherical. Moreover, the iron release of AGSP-Fe(III) during simulated gastrointestinal digestion was exhibited, and its good iron supplementary efficiency was also shown using Caco-2 cells. In addition, compared to FeCl₃, AGSP-Fe(III) showed better solubility and stability in the presence of polyphenol/trypsin. The present study demonstrated the potential of AGSP-Fe(III) as a novel iron supplement.