The formulation of bilayer films is a strategy aimed at combining the advantages and properties of different film-forming materials. Bilayer films based on pectin and brea gum were formulated and their functional properties studied and compared with those presented by single layer films of each component. The micrographs and surface properties confirmed that the bilayer films can maintain their identity and prevent delamination. The mechanical properties of the films depended on the characteristics of the polymers and their interactions, and the bilayer films showed prevalence of the brea gum properties. The brea gum films showed high solubility that influenced the bilayer film solubility. The water vapour permeability of the bilayer films was dependent on the material that was exposed to the side where desorption occurred. The bilayer films presented lower water vapour permeability than the brea gum films but higher than that of pectin films of similar thicknesses. The differential properties of each layer of bilayer films make them potentially interesting for controlled drug release.

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The scaling up of the wet process and the design of a coating line to produce edible films, require the consideration of several factors such as, the film formulation, drying kinetics of the films, and the selection of a suitable support material in which to pour the solution. This work aimed to select the most suitable material for the construction of a conveyor belt for the fabrication of edible films through the wet process. The surface properties of the starch film-forming solution were determined. Several commercial materials for conveyor belts were tested. The film-forming solution spreadability and work of adhesion were determined. The mechanical behavior of the dry film was evaluated through mechanical properties and peeling resistance. All materials tested showed good performance under the operational conditions assayed to obtain edible films. Finally, the polyurethane band was chosen due to its appropriate performance and lower cost.