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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<0.05). In conclusion, some properties of agar and gelatin films can be improved by making bilayers film of both biopolymers. 

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In this study, walnut oil emulsions stabilized with chia seed mucilage with different oil percentages (10, 20, 30 and 50%) were prepared by the Pickering method. Then, the best emulsion was used in the preparation of bilayer and combined edible films based on sodium carboxymethyl cellulose, and the effect of this oil emulsion on the physical properties (permeability, contact angle, turbidity, tensile strength, strain at break and Young's modulus) of the produced films was investigated. The results showed that the walnut oil emulsion with 10% oil had the highest stability after 14 days. Moreover, the droplet size (D₅₀) of the emulsion (10% oil) was 886 nm, which was in the range of below one micrometer. Then, the walnut oil emulsion stabilized with chia seed mucilage (10% oil) was added to the edible films based on sodium carboxymethyl cellulose in bilayer and combined form. The results showed that adding walnut oil emulsion to sodium carboxymethyl cellulose films in a combined form increased turbidity and yellowness index compared to the bilayer films. There was no significant difference (p>0.05) in water vapor permeability between the bilayer and combined films, but the films containing walnut oil had lower water vapor permeability than the control sample. The results indicated a decrease in tensile strength in the bilayer and combined films with the addition of walnut oil emulsion. Furthermore, the bilayer film containing walnut oil emulsion had the lowest Young's modulus (41.68 MPa) and the highest strain at break point (0.18). In general, the findings of this study showed that valuable walnut oil in the form of an emulsion stabilized with chia seed mucilage m in the structure of sodium carboxymethyl cellulose edible films not only can create an edible film, but also improve the physical properties of the films.