A hydrophobic peptide fraction that enhances the water dispersibility of curcumin

The present study describes the complexation between curcumin (Cur) and a peptide mixture (Pep). Pep was prepared by enzymatic hydrolysis of casein and used as an excipient for poorly water-soluble Cur. An aqueous solution of Pep and an acetone solution of Cur were mixed and lyophilized to obtain a white-yellow powder of the peptide and Cur complex (Cur-Pep). The water dispersibility of Cur was enhanced by the complexation with Pep. Pep was fractionated using ammonium sulfate precipitation and ultrafiltration to identify which peptides preferentially interact with Cur. Relatively hydrophobic peptides with high molecular weights (>5 kDa) were more effective in enhancing the water dispersibility of Cur than other fractions. Cur-Pep dispersed under acidic and neutral conditions, at which amphoteric Pep is positively or negatively charged. Cur-Pep exists as a hydrocolloid with particle size 160–330 nm in aqueous media.