Reduction of Water Vapor Permeability in Food Multilayer Biopackaging by Epitaxial Crystallization of Beeswax

In this paper, multilayer pectin-beeswax/colophony-pectin (P-BC-P) films including different proportions of beeswax/colophony mixtures were prepared in order to reduce the water vapor permeability. FTIR, XRD, DSC, polarized light microscopy (PLM), and water vapor permeation assays were performed. Characterization techniques showed (i) polar interactions between beeswax and colophony at the amorphous phase, (ii) changes in beeswax crystalline phase from sponge-like to needle-like structure, and (iii) formation of a eutectic mixture at BC3 70/30 ratio which guides the epitaxial crystallization of beeswax. Pure pectin films showed low resistance to the water vapor permeation (361 x 10(-13) g m m(-2) s(-1) Pa-1), while multilayer films showed major control over the transport process. P-BC3-P showed one of the lowest water vapor permeability (WVP) values (56 x 10(-13) g m m(-2) s(-1) Pa-1) and the closest WVP value to that of polyethylene films (LDPE 5.8 x 10(-13) g m m(-2) s(-1) Pa-1). This result was attributed to the ordered crystalline structure reached by the epitaxial crystallization of beeswax within the hydrophobic phase.