Abstract

Polyvinyl alcohol/chitosan (PVA/CS) films, which may be a good alternative for food packaging, have a limited vapour water barrier. In this study, the effect of β-chitin micro- and nanoparticles (MPs and NPs, respectively) obtained from jumbo squid (Dosidicus gigas) pens on the water vapour permeability (WVP) of PVA/CS films was investigated. The β-chitin MPs (sizes of 128 µm; MpQ128) were obtained by milling β-chitin squid, and an aqueous acid dispersion of MpQ128 was ultrasonicated to obtain NPs (NpQ; Z-average of 300–400 nm; Z-potential of 40 mV). In addition, PVA/CS films with three different proportions (90/10, 80/20, 70/30) were prepared. The addition of 1% or 5% MpQ128 did not increase the thickness or tensile strength (TS) of these films. The percentage elongation (%E) of the film increased only in the PVA/CS film with a proportion of 70/30. The addition of NPs (1% or 5%) in the PVA/CS 70/30 film did not increase the film thickness; however, the TS and %E increased significantly compared to those of the control sample, and the increase in %E was significantly higher with NPs than with MPs. Moreover, the PVA film exhibited biphasic water loss kinetics, and the film showed three-phase behaviour for CS amounts of 10%, 20%, and 30 %. The WVP values did not significantly change for different PVA/CS proportions during each experimental period. However, in the second period (7–15 days), the WVP was significantly lower than in the first (1–6 days) and third periods (16–21 days). The addition of MPs or NPs did not significantly decrease the WVP compared to that of the control sample. Nevertheless, it decreased slightly for 1% or 5% NP additions in the films. The effectiveness of β-chitin NPs in reducing the WVP can be improved by avoiding the aggregation of NPs in hydrophilic PVA/CS films.