Characterization of zein / hyaluronic acid complex colloidal nanoparticles stabilized Pickering emulsions as a delivery vehicle of curcumin

In this work complex nanoparticles composed of zein and hyaluronic acid (HA), referred to as ZHPs, were fabricated through the combined effects of hydrogen bonding and electrostatic attractions. Compared to zein particles, ZHPs exhibited a larger mean particle size and a reversal in zeta potential from positive to negative. The three-phase contact angle (θ_o/w) of ZHPs with a 10:3 ratio was measured at 88.9°, indicating their suitability for stabilizing Pickering emulsions. Both droplet diameter and the emulsified phase volume fraction of the emulsions were significantly affected by the concentration of ZHPs and the oil phase ratio. Confocal laser scanning microscopy revealed that ZHPs adsorbed on the oil-water interface formed a compact interfacial layer. Rheological analysis showed that emulsions displayed shear-thinning behavior and exhibited characteristics of an elastic gel network. Moreover, the Pickering emulsions stabilized by ZHPs markedly suppressed curcumin degradation under UV exposure compared to both bulk oil and conventional emulsions. Results from vitro digestion indicated that the release of free fatty acids (FFAs) and the bioaccessibility of curcumin were enhanced in ZHP-stabilized emulsions relative to bulk oil. Overall, the findings support the potential of ZHP-stabilized Pickering emulsions as efficient delivery vehicles for food and pharmaceutical applications.