The water uptake and swelling of the DCA beads in pH
6.8 phosphate buffer was higher than those in distilled water
because calcium ions cross-linked with alginate were rapidly
exchanged with sodium ions in phosphate buffer. The partial formation of SA induced water uptake
into the beads. Moreover, calcium alginate gels could be solubilized
by the addition of phosphate ion, which acted as calcium
ions complexing agent at a pH above 5.5. Incorporation of XG into the DCA beads promoted the water uptake and swelling properties in pH 6.8 phosphate
buffer because XG provided higher water uptake capacity
than SA