Abstract: To overcome the limitations of the oral limitations of capsaicin, this study prepared a thiolated chitosan-zein nanoparticle delivery system loaded with capsaicin. The preparation process was optimized based on particle size and loading capacity, and the efficiency of encapsulation was verified by fluorescence spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). The stability and release properties of the capsaicin-loaded nanoparticles were also evaluated during in vitro digestion. The results showed that at a thiolated chitosan to zein to capsaicin of 10:10:1, the particle size of the nanoparticles, which were observed to be regular spherical in shape, was (76.05 ± 1.06) nm, and the loading capacity was (36.85 ± 1.22) μg/mg. The nanoparticles were formed through hydrogen bonds and hydrophobic interactions. In addition, the nanoparticles had good pH stability and ionic strength stability, which could effectively delay the release of capsaicin during simulated digestion in vitro, and the release ratio after 4 h digestion was only (40.08 ± 4.28)%. The nanoparticles can be used for oral delivery of capsaicin.

Key words: thiolated chitosan; capsaicin; nanoparticles; in vitro simulated digestion; sustained release