Abstract
Biopolymer-based films are an alternative to replace plastic packaging. These films may be produced from various raw materials, such as polysaccharides and proteins. Among them, the most used are starch and gelatin, which have good filmogenic properties, although they present some limitations. These isolated macromolecules produce films with good mechanical properties (gelatin) and adequate barrier properties (starch). Thus, the use of these polymers in association to produce blends becomes a good option to overcome the weaknesses of each macromolecule when used individually. Also in this context, starch physicochemical characteristics can be modified by ozonation to improve the interaction between the macromolecules. The aim of this work was to study the mechanical properties and the water vapour permeability (WVP) of gelatin:arrowroot starch blends. Native starch and treated with ozone at three times (5, 10 and 20 minutes) were studied. The blends were produced by casting and dried in an oven at 30 °C. The mechanical properties were measured by tensile tests and WVP was determined by gravimetry. Visually, the blends were homogeneous without phase separation. In general, the blends produced with native starch presented better WVP results and no difference for the mechanical properties. In other words, longer treatment time with ozone resulted in higher water vapour permeability and did not change the mechanical properties when compared to blends formulated with native starch. Therefore we can conclude that the ozonation time, for the studied conditions, was not enough to improve the mechanical properties and besides that increased blend WVP.
