Enhancing the stability of zein/fucoidan composite nanoparticles with calcium ions for quercetin delivery.

In this study, zein and fucoidan-based composite nanoparticles were prepared by the antisolvent precipitation method. The effects of different calcium ion (Ca, 0-3.0 mM) concentrations on the stability of the composite nanosystems loaded with quercetin were studied under different conditions (pH, temperature, salt concentration, and ultraviolet light irradiation), and the composite nanoparticles were characterized. Electrostatic interactions, hydrogen bonding, and hydrophobic interactions are the main forces underlying the formation of composite nanoparticles. The addition of Ca led to improved release of the active substances from the composite nanoparticles in simulated digestive solutions (especially when the Ca concentration was 1.5 mM). The composite nanosystems based on alcohol-soluble proteins and anionic polysaccharides with added Ca can be potentially applied for the delivery of active substances.