Tailoring physico-mechanical and antimicrobial/antioxidant properties of biopolymeric films by cinnamaldehyde-loaded chitosan nanoparticles and their application in packaging of fresh rainbow trout fillets

In this study, cinnamaldehyde (CIN)-loaded chitosan nanoparticles (CCNPs) were fabricated and embedded into chitosan/poly(vinyl alcohol)/fish gelatin (CPF) ternary matrices to improve the physico-mechanical and biofunctional performances of the films. The particle size and ζ-potential values of the CCNPs were 370.3 nm and +32.2 mV, respectively. SEM images revealed that the CCNPs were homogeneously dispersed in the CPF ternary film matrices, thereby filling void spaces in the composite matrix, and significantly improving the bionanocomposite films tensile properties (from 28.33 ± 2.17 MPa to 33.0 ± 1.28 MPa) (p < 0.05). However, the water barrier properties and water contact angle of the CPF films were not significantly influenced by the nanofiller embedding. Although the incorporation of the NPs decreased the light transmittance of the films, it provided the CPF-CCNPs nanocomposite films with excellent UV-barrier properties. ATR/FT-IR spectroscopy and X-ray diffraction analysis demonstrated the formation of hydrogen bonds between the NPs and polymer molecules. TGA and DSC studies revealed that CPF-CCNPs nanocomposite films presented better thermal stability than the neat CPF film. AFM imaging also indicated a re-organization of the surface of the nanocomposite films due to the incorporation of the NPs. Release studies suggested that the CPF-CCNPs bionanocomposite film exhibited sustained release behavior of CIN. Likewise, the bioactive nanocomposites displayed antibacterial activity against food-borne pathogens such as Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative bacteria (Escherichia coli and Salmonella enteritidis). The bionanocomposite films exhibited in vitro DPPH radical scavenging activity (∼16.4%) and ferric reducing power at the maximum CIN loading concentration. Additionally, analysis of storage quality indices (pH, TBARS values, color, and microbiological analyses) revealed the shelf-life of rainbow trout fillets wrapped in CPF-CCNPs0.25 was extended to 12 days.