Application of response surface methodology and spectroscopic approach for investigating of curcumin...

This study aimed at encapsulation of poor water-soluble curcumin so that it could be utilized in various food products as a functional ingredient. Biopolymer nanoparticles were assembled from sodium caseinate and gum arabic using electrostatic complexation in the presence of nonionic surfactant Tween 20. Fourier transform infrared spectroscopy was used to investigate the interactions of curcumin with protein, polysaccharide and surfactant. The effects of sodium caseinate (A), gum arabic (B), Tween 20 (C) and pH (D) on responses were studied using a three-level four-factor Box-Behnken design. For each response, a second-order polynomial model was developed. For optimum nanoencapsulation of curcumin, the variables concentration of sodium caseinate, concentration of gum arabic, pH and concentration of Tween 20 were 0.21, 0.5, 5 and 0.14 wt% respectively. The particles were characterized by ζ-potential measurement. Spectroscopic results and data modelling, showed interaction of curcumin with sodium caseinate, gum arabic and Tween 20. Also, the nonionic surfactant Tween 20, influenced the electrostatic interaction between sodium caseinate and gum arabic.