Chitosan nanoparticles loaded with royal jelly: Characterization, antioxidant, antibacterial activities and in vitro digestion

Nano-embedding has appeared as a feasible technology to improve the high-quality utilization of royal jelly (RJ). Therefore, the ionic gelation method was proposed to prepared chitosan nanoparticles loaded with royal jelly (RJNPs) and the characterization and biological activity of RJNPs were evaluated in this study. Fourier-transform infrared spectroscopy, differential scanning calorimetry and x-ray diffraction results showed that the methyl and methylene groups of royal jelly combine with the amino groups of chitosan (CS) to become an amorphous polymer. In addition, the 48.68 % encapsulation efficiency and 31.90 % loading capacity were obtained under the optimal ratio of 1:1 RJ to CS, and the average particle size was <80 nm. The antioxidant activity of RJNPs gradually increased with the increase of the RJ proportion. Interestingly, the antibacterial activity on gram-positive bacteria was better than gram-negative bacteria. Most important, RJNPs exhibited better stability and digestibility rather than single RJ. Overall, these findings indicated that RJ can be embedded in chitosan, and RJNPs exhibited good thermal stability, antioxidant activity, antibacterial activities and bioavailability, which was important for the development and application of the high-quality utilization of RJ.