Thiol-modified hyaluronic acid improves the physical stability of curcumin-zein nanoparticles by forming disulfide bonds with zein.

Zein-based nanoparticles have been developed in the food industry. However, their poor pH stability and unfavorable ionic strength stability remain a challenge even with the use of polysaccharides (such as hyaluronic acid) as stabilizers. To address this shortcoming, an improved strategy based on the disulfide bonds between thiol-modified hyaluronic acid (HASH) and zein was proposed. In this study, curcumin-zein nanoparticles (ZNs-HASH) were prepared with HASH as a stabilizer. The ZNs-HASH displayed similar particle sizes and spherical structures with ZNs and ZNs-HA (HA as a stabilizer). The Fourier transform infrared spectroscopy demonstrated the formation of disulfide bonds between zein and HASH. Among the three formulations tested, ZNs-HASH exhibited the highest pH and salt ion stability and the strongest antioxidant capacity. This study provided new insights for the improvement of physical stability of zein nanoparticles and the development of oral bioactive substances by chemical modification of natural polysaccharides.