The structure, antioxidant activity, and stability of fish gelatin/chitooligosaccharide nanoparticles loaded with apple polyphenols

Apple polyphenols (APs) with multiple biological effects have attracted extensive attention due to their broad opportunities for application. However, the use of APs is hampered by their instability in the face of environmental changes. Designing efficient carriers to improve the bioavailability of APs is the key to solving these problems. In this study, gelatin-chitooligosaccharide nanoparticles produced by the Maillard reaction (GCM) were fabricated to encapsulate AP, and the structure, antioxidant activity, and stability of the GMM-AP nanoparticle system were evaluated.The results of endogenous fluorescence spectrum, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction, and simultaneous thermal analysis confirmed structural changes and interactions between GCM and AP. Combination with GCM did not adversely affect the antioxidant properties of AP, and the GCM-AP nanoparticles possessed superior temperature and storage stability. In comparison with fish gelatin-apple polyphenol nanoparticles, the GCM-AP nanoparticles were more stable at a wider pH range, and were more resistant to the electrostatic shielding effect of NaCl. After simulating gastric digestion, the particle size and polydispersity index (PDI) of GCM-AP nanoparticles were almost unchanged.The findings suggest that GCM nanoparticles loaded with AP could be used as good carriers with good antioxidant activity and stability. This study therefore provides a theoretical foundation for the development and industrial application of food functional factors. © 2023 Society of Chemical Industry.