Packaging Applications of Polyhydroxyalkanoates (PHAs) - Polyhydroxyalkanoate (PHA) Based Blends, Composites and Nanocomposites - page 224

properties and impact strength than PHB/PIP blends, which were immis-
cible. 35 Combined with synthetic plastics or starch, PHAs make excellent
packaging films. 38
Levkane et al. 39 have investigated the pasteurisation effect in a meat salad
with conventional packaging (PE, PP) and packaging with a biopolymer (PLA,
PHB) and have found that PHB films can be used successfully to pack this type
of food. Haugaard et al. 40 have found that orange juice and sauce packaged in
PHB resulted in the same quality changes when compared to the same
products packaged in HDPE. This study has shown that juices, other com-
mercial acid beverages, sauces and other fatty foods can be packed in PHB.
In another study, conducted by Shen et al., 41 thermoplastic starch (TPS)
blended with PHA had a positive effect on the barrier and hydrolytic prop-
erties and UV stability of a starch-based film. With this blend, it was possible
to reduce the processing temperature, resulting in less degradation of the
starch. 41
Biopolymers satisfy environmental concerns, but they may have some
limitations in terms of performance, such as heat resistance, barrier prop-
erties and mechanical properties associated with costs. Some PHA/PHB
films may have increased fragility (due to high glass transition temperatures
and melting temperatures), greater stiffness, less impact resistance and less
heat resistance. All these factors are limiting the application of these films in
food packaging. 42-44

d n 2 r 4 n g | 8

9.3 Conclusion
Over the last few decades, polymers have replaced conventional materials
(metals, ceramics, paper) in packaging applications. The use of synthetic
polymers in food packaging is growing more and more, where they provide
mechanical, chemical, and microbial protection from the environment and
allow product display. Now, concerns about the environment and the need to
reduce the dependency on fossil fuels has led to the search for alternatives to
traditional packaging materials, such as biodegradable materials (PHB, PHB-
co-HV, PHB-b-HPE, and others). Therefore, these types of packaging materials
need more research to result in products with higher added value, such as
research into the introduction of smart molecules able to give information
about the properties of the food inside the package and its nutritional value. It
is necessary to research these types of materials to improve barrier properties,
to ensure integrity of foods, to incorporate labels and intelligent packaging,
giving the consumer the opportunity to have more detailed information about
the product compared to current packaging systems.

.

References
1. A. B. Reis, Caracterizaç˜o de filmes e coberturas de quitosana aplicados em
papel˜o ondulado, Dissertaç˜o de Mestrado, Unicamp-FEQ, Campinas-
SP, 2005, p. 74.