Effect of latex coating on the physical properties of Calcium Alginate beads

Alginate has been commonly applied in encapsulation due to its gelling capacity, biocompatibility, and environmentally friendly properties. Alginates can produce a thermally stable and biocompatible hydrogel in the presence of divalent cations such as calcium. However, the high porosity and low physical stability of calcium alginate beads can lead to encapsulation loss and degradation of encapsulated materials. It is speculated that latex coating on the beads can overcome the issues. Hence, this study aims to investigate the effect of latex coating on the physical properties of Ca-alginate beads. An extrusion dripping method was adopted to produce Ca-alginate beads. The beads were multilayer coated with a 5% latex solution. The size and shape of uncoated and coated beads were analyzed using 2D image analysis. The thickness of the latex coating layers was measured layer by layer using a thickness gauge. The results indicated that as the number of coating layers increased, the size of the beads also increased. However, the sphericity of the beads is decreased as the number of layers of latex coating is increased. The thickness of the latex coating increased layer by layer, from 0.017 mm to 0.112 mm. In short, the calcium alginate beads can be coated by latex. The diameter of the bead is significantly increased after two layers of latex coating, and the sphericity of the beads is reduced considerably after two layers of latex coating.