Background and Objectives: In addition to the numerous benefits of biopolymeric nanocomplex, it has drawbacks including difficulty in strict control of particle size and to prevent particle agglomeration. In this study, the influence of Tween 20 on the electrostatic interaction between sodium caseinate and gum Arabic was evaluated.

Materials and Methods: Initially, the organic phase (curcumin in ethanol) was introduced to aqueous phase (sodium caseinate, gum Arabic and Tween 20). Then by reducing the pH, the nanoparticles were formed. To evaluate the effects of the independent variables on the responses, the Box-Behnken design was used. The antioxidant activity of samples was evaluated by 1, 1diphenyl 2 picryl hydrazyl radical inhibition assay.

Results: Tween 20 has a significant effect on particle size, and particle size distribution (p<0/0001). Sodium caseinate and Tween 20 have significant effects on the encapsulation efficiency and antioxidant activity of curcumin nanocapsules (p<0/0001). Using desirability function, optimal processing conditions was achieved in the sodium caseinate concentration (0/28%), Arabic gum concentration (0/5469%), Tween 20 concentration (0/18%) and pH (5.02).

Conclusion: Due to the high encapsulation efficiency and antioxidant activity of curcumin nanocomplex and no need for high energy equipment such as homogenizer, this method is suggested as a simple, fast and low-energy technique.

Keywords: Curcumin, Nonionic surfactant, Protein/polysaccharide nanocomplex, Antioxidant activity