Barrier Properties and Surface Characteristics of Edible, Bilayer Films

Various formulations and methods of fabricating a film consisting of edible hydrocolloids and lipids were investigated. Two formulations consisting of a methylcellulose base layer and a beeswax layer, deposited either from a molten state (Wax‐M film) or from an ethanolic solution (Wax‐S film), were examined for water vapor permeability (WVP), oxygen permeability and other physical properties. WVP values (g‐mil‐m −2 ‐day −1 ‐mm Hg −1 ) for the Wax‐M and Wax‐S films were 0.5 ± 0.05 and 1.6 ± 0.4, respectively. WVP of the two films did not change significantly after storage for 1 wk at ‐40°C. Oxygen permeability values (g‐cm‐cm −2 ‐sec −1 ‐mm Hg −1 × 10 −12 ) for the Wax‐M and Wax‐S films were 0.021 ± 0.002 and 0.007 ± 0.002, respectively. The Wax‐M film had a more uniform surface topography than the Wax‐S film.