Development and Characterization of Eugenol-Loaded Pectin/Soy Protein Isolate/Curcumin Films for Grass Carp Packaging...

Biodegradable and biocompatible active packaging films have a great potential to replace traditional petroleum-based products in food packaging. Herein, soy protein isolate (SPI)/pectin-based films incorporating curcumin (Cur) (SPC) and eugenol (1%-5%) were prepared using the solution casting method. The physicochemical, microstructural, and biological properties of the composited films were investigated. Results showed that the incorporation of Cur and eugenol significantly improved the films' physical and chemical properties by enhancing their mechanical strength, hydrophobicity, UV light blocking ability, and water vapor barrier performance, especially at an eugenol concentration of 3%. Additionally, SEM results showed eugenol (<3%) was uniformly distributed in the polymer matrix and filled the voids in the composite films. FT-IR and XRD confirmed the existence of intermolecular interactions between eugenol and the film-forming matrix. Notably, the film containing 3% eugenol (SPC-E3) showed excellent antioxidant activity (90.44 ± 2.88% for DPPH and 64.92 ± 0.50% for ABTS) and superior antibacterial activity (with inhibitory zones of 17.84 ± 0.67 mm and 17.66 ± 0.11 mm for E. coli and S. aureus, respectively). During preservation, the SPC-E3 film slowed the changes in surface color, pH, and total volatile basic nitrogen (TVB-N) levels of grass carp, extending their shelf life to 14 days under refrigeration. These findings suggest that the SPC-E3 film shows great potential for active food packaging applications.