Preparation and characterization of the physical and mechanical properties of agar/fish gelatin bilayer films for food packaging

In this study an agar/gelatin bilayer film was produced from agar and gelatin monolayers using the casting method in two phases. Then, the characteristics of this bilayer film, including water vapor permeability (WVP), water solubility, water absorption, mechanical and optical properties were compared with those of monolayer films. The results showed that WVP of the bilayer film (3.25×10-10 g/msPa) was significantly lower than the agar (3.90 × 10-10 g/msPa), and gelatin (4/32×10-10 g/msPa). Absorption of UV light by bilayer film was significantly higher than the single-layer agar and gelatin films. Although the tensile strength of the bilayer film (10.8 MPa) was higher than the single-layer gelatin (2.86 MPa), it was lower than the single layer of agar film (30.49 MPa) (P