Utilization of biopolymers to stabilize curcumin nanoparticles prepared by the pH-shift method: Caseinate, whey protein, soy protein and gum Arabic

The water-dispersibility of hydrophobic polyphenols can be enhanced using nanotechnology-based approaches. Previous studies have shown that curcumin nanoparticles fabricated by a pH-shift method have a good water-dispersibility and a high loading capacity. Moreover, this method has considerable potential for large-scale commercial production of nutraceutical-loaded delivery systems for food applications. In this study, four kinds of amphiphilic biopolymers (sodium caseinate (SC), whey protein isolate (WPI), soy protein isolate (SPI), and gum Arabic (GA)) were used to coat curcumin nanoparticles (CNPs) produced by the pH-shift method. The encapsulation efficiency, loading capacity, particle dimensions, electrical potential, morphology, and stability of the CNPs were characterized. The four biopolymers could all stabilize aqueous dispersions of the CNPs and had a relatively high loading capacity. The maximum loading capacities of the SC, WPI, SPI, and GA-coated CNPs were 27%, 21%, 12%, and 9%, respectively. The resistance of the biopolymer-coated CNPs to changes in environmental conditions depended strongly on biopolymer type. GA coatings gave the best pH and salt stability, whereas SC and SPI gave the best thermal stability.