Development and characterization of soybean protein isolate and fucoidan nanoparticles for curcumin encapsulation.

Curcumin (Cur) is a natural polyphenol with beneficial biological and pharmacological activities; however, it has limited applications owing to its low solubility and light sensitivity. The protein-polysaccharide complex can effectively embed lipid-soluble drugs to increase their stability and dispensability in aqueous solutions. Soybean protein isolate (Spi) and fucoidan (Fuc) were used as a polymer matrix, and core-shell nanoparticles were prepared to encapsulate Cur via electrostatic interaction under acidic and neutral conditions. The structure of the Spi-Fuc nanoparticles was studied via Fourier-transform infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy. Concurrently, we evaluated the efficacy of the nanoparticles based on stability, drug loading rate, and simulated release. Our results showed that the Spi-Fuc nanoparticles (size, approximately 236.56 nm) had a spherical, core-shell structure and that they could effectively load Cur with an embedding efficiency of >95%; moreover, the system had long-term dispersion stability. Thus, we provide a simple method for Cur delivery, which can also be potentially used for delivering lipid-soluble active ingredients.