Curcuminwas dissolved in ethanol at the concentration of 4 mg/
mL and filtered through syringe filter (0.2 mm) to remove any undissolved
crystal. Soluble starch was dissolved in distilled water at
the concentration of 5 mg/mL and heated at about 80 C to totally
solubilize the starch. When the starch solution turned to transparent,
certain volume of curcumin ethanol solution was pipetted
slowly into the heated starch solution under stirring. Four cur@star
samples were prepared by varying the weight ratio of curcumin to
soluble starch (1 wt%, 2 wt%, 3 wt% and 5 wt%). Ethanol was
simultaneously removed by the hot starch solution. To increase
encapsulation efficiency of curcumin and reduce the size of the
nanoparticles, manufactured cur@star solution was subjected to
ultrasonication treatment at the power output of 150Wfor 5 min in
the ice bath. Freeze dried power of cur@star was retrieved after
60 h of lyophilization at 60 C. Cur@star powder has characteristic
yellowish color of curcumin and was kept at 20 C until use.