Preparation and characterization of nanoemulsion encapsulating curcumin

Curcumin is the most active and least stable bioactive component of turmeric (Curcuma longa) plant. In the present study, an attempt has been made to overcome the instability during processing and bioavailability problems of curcumin by nanoencapsulation technology and the effect was evaluated by simulated digestion study. Curcumin was encapsulated in medium chain triglyceride oil droplets of nanoemulsion prepared by ultrasonification using whey protein concentrate-70 and Tween-80 as emulsifiers with an encapsulation efficiency of 90.56 ± 0.47%. The prepared nanoemulsion has particles of average diameter 141.6 ± 15.4 nm and zeta potential of −6.9 ± 0.2 mV. In vitro release kinetics of curcumin from nanoemulsion by simulated gastrointestinal studies showed that the curcumin nanoemulsion was relatively resistant to pepsin digestion but pancreatin causes release of curcumin from nanoemulsion. The slow release of curcumin from the nanoemulsion was supposed to increase bioavailability. The total antioxidant activity of curcumin nanoemulsion was reduced from 3.53 ± 0.11 μM Trolox/mg of curcumin to 3.33 ± 0.02 μM Trolox/mg of curcumin after encapsulation. The prepared nanoemulsion was stable to pasteurization, different ionic strengths (0.1–1 M) and pH ranging from 3.0 to 7.0. The study has important implication in the formation and design of encapsulated bioactive systems.