Preparation of Chitosan/Rosemary Extract Nanoparticles and their Application for Inhibiting Lipid Oxidation in Grass Carp (Ctenopharyngodon idellus) during Cold Storage

This study investigated a preparation of chitosan/rosemary extract nanoparticles (CS/RE-NPs) based on the principle of ionic gelation and their application for inhibiting grass carp lipid oxidation. CS/RE-NPs were found to have a rosemary extract (RE) encapsulation efficacy of 40.33%, average particle size of 199.90 nm, and zeta-potential of 35.60 mV. Structural analysis using UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) indicated that the RE s were well incorporated into the CS-NPs. Treatment of the CS/RE-NPs inhibited lipid oxidation of the grass carp during cold storage, and the peroxide value (PV), thiobarbituric acid-reactive substance (TBARS) value, and lipoxygenase (LOX) activity of the CS/RE-NP-treated samples were lower than those of RE and CS-NP-treated samples, respectively. CS/RE-NP-treated samples also slowed the growth of bacteria, enhanced the organoleptic quality, and prolonged the shelf life of grass carp. This study suggested that CS/RE-NPs can be used as an antioxidant delivery system to inhibit lipid oxidation and improve food quality.