Physicochemical properties, antimicrobial activity and oil release of fish gelatin films incorporated with cinnamon essential oil

Fish skin gelatin films incorporated with various concentrations of cinnamon essential oil (CEO) were prepared and characterized. The results showed that tensile strength (TS), elongation at break (EAB), and water content (WC) of the gelatin based film decreased with the increasing concentrations of CEO, but water vapor permeability (WVP) increased. Addition of CEO improved light barrier property of the film. The Scanning electron microscope (SEM) showed that the heterogeneous surface and porous formation appeared in gelatin-CEO films. Fourier transform infrared spectroscopy analyses (FTIR-ATR) spectra indicated the interactions existed between gelatin and CEO. The gelatin-CEO films exhibited good inhibitory effects against the tested microorganisms (Escherichia coli, Staphylococcus aureus, Aspergillus niger, Rhizopus oryzae, and Paecilomyces varioti) and their antifungal activity seemed to be more effective than the resistance to bacterial growth. In vitro release studies showed an initial burst effect of CEO release and that subsequently slowed down at 40 °C, but the initial burst release was not obvious at 4 °C. The obtained results suggested that incorporation of CEO as a natural antimicrobial agent into gelatin film has potential for developing as active food packaging.