Incorporation of graphene oxide to enhance fish gelatin as bio-packaging material

•Gelatin films with various GO concentrations and sonication times were produced.•Higher GO content with longer sonication time increased the tensile strength.•Modified films also had lower moisture content.•Gelatin/GO films had excellent UV and light barrier properties than the control. Gelatin composite films with various concentrations (0.5 %–2.0 % w/w) of graphene oxide (GO) and different sonication treatment times (1.5 and 2.5 h) were prepared by using the casting method. The mechanical, optical, water barrier, and morphological characteristics of the composite films were determined. Composite films with GO concentrations of up to 2.0 % at a sonication time of 2.5 h produced thinner films with up to 34 % and 76 % improvement in the tensile strength (TS) and Young’s modulus (YM), respectively. Additionally, the GO loadings of up to 2 % had excellent light barrier properties as compared to those of a neat gelatin film. The results also showed that the incorporation of GO irrespective of the sonication time reduced the water vapour permeability (WVP) and solubility (p < 0.05), because of the denser networks as supported by the scanning electron microscopy (SEM) images. However, the increase in the GO level did not have any effect on the WVP. The X-ray diffraction (XRD) results revealed partially crystalline films, and the Fourier transform infrared (FTIR) spectra showed some chemical interactions between gelatin and GO.