Studies on the pH-dependent swelling properties and morphologies of chitosan/calcium-alginate complexed beads

Chitosan/calcium‐alginate beads were prepared by a coacervation method in aqueous medium. Their swelling properties and morphologies were studied. Complexed beads with a mean diameter of 500 μm were obtained by dropwise addition of a sodium alginate solution into a chitosan‐calcium chloride solution. From scanning electron microscopic studies, we observed that chitosan modifies the morphology of calcium‐alginate beads. The swelling properties of chitosan/calcium‐alginate beads are different from those of calcium‐alginate beads. In the case of the calcium‐alginate beads, the swelling volume increases as the pH of the medium increases. However, chitosan/calcium‐alginate beads show a maximum swelling volume at pH 9.0.