This
behaviour could be related to structural modifications of
chitosan-cassava starch-gelatin network that occurs when
63 g of glycerol per 100 g of chitosan are added. Initially,
chitosan-based films formulated with lower mass fraction
of glycerol form a loose structure, which facilitates
the water vapour permeation, then, when glycerol reached 63 g of glycerol per 100 g of chitosan, the formation of
loose structure was avoided, a more compact structure
was formed, and this probably resulted in lower WVP
values.