3.1. Size, polydispersity index (PDI), zeta potential, loading ability & efficiency and water solubility
During the sample preparation, curcumin ethanoic solutionwas mixed with soluble starch dissolved in distilled water at about 80 C. High temperature was employed to fully dissolve starch and remove organic solvent at the same time. After mixing, the solution was treated with ultra-sonication for 5 min in order to increase the loading efficiency and the stability of the nanoparticles as previously reported (Yoon et al., 2014). At loading level of 1 wt%, the cur@star solution appears transparent and isotropic with yellowish color of curcumin (Fig. 1 A-b). While higher curcumin loading renders the solution opaque (Fig. 1 A-c, d, e). When loaded at 5 wt%,