pH-Driven Self-Assembly of Functional Lysozyme–Hyaluronan Complex Colloidal Nanoparticles for the Oral Delivery of Lutein

Despite its various health-promoting bioactivities, poor water solubility, chemical instability, and low bioavailability of lutein have limited its further application in the food industry. This paper reports a simple and a green pH-driven method to synthesize lutein-loaded lysozyme–hyaluronan complex colloidal nanoparticles (Lut@LYS-HANPs) able to overcome the aforementioned shortcomings. The fabricated Lut@LYS-HANPs exhibited a stabilized particle size (164 nm), negative surface zeta-potential (−44.86 mV), excellent long-term storage stability, and favorable redispersibility. The encapsulation efficiency and loading ability of lutein in the prepared Lut@LYS-HANPs were 96.23 and 11.07%, respectively. Infrared spectra demonstrated that the dominant interaction forces behind the formed Lut@LYS-HANPs were hydrogen bonds and hydrophobic and electrostatic interactions. The circular dichroism spectra indicated that lutein incorporation mainly changed the α-helix and β-sheet contents of lysozyme. Besides, the constructed Lut@LYS-HANPs significantly improved the chemical stability and bioavailability of lutein. Furthermore, the excellent biocompatibility of the prepared Lut@LYS-HANPs was confirmed by in vitro cell experiments. Overall, the designed Lut@LYS-HANPs may be suitable not only for the efficient delivery of lutein but also for improving its stability and bioavailability in functional foods.