As shown in Table 1, Ch films exhibited better water vapour barrier properties than gelatin ones (0.367 vs. 0.826 g mm/ kPa h m2). Gelatin films with a higher amount of protein and thickness could adsorb more water from the environment, due to the presence of a wide range of hydrophilic amino acids in the gelatin (McHugh et al., 1993). Water vapour permeability of both biopolymers has been previously studied by other authors. Values for gelatin were comparable with those reported for cold-water fish gelatin films (Chiou et al., 2008) (0.857 g mm/kPa h m2). The low WVP of fish skin gelatin films is related to their high hydrophobicity due to the reduced amount of proline and hydroxyproline compared to the mammalian gelatins.