PHB packaging for the storage of food products

Polymers are widely used for food packaging. However, due to their slow degradation and the predicted exhaustion of the world petroleum reserves, the use of polymers brings significant environmental problems. Therefore, it is necessary to replace them with bioplastics that degrade in a short time when exposed to a biologically active environment. The possibility for the use of PHB, poly(3-hydroxybutyrate), in food packaging was investigated in this study. This polymer, through the injection process, was used to manufacture packaging. The packaging was evaluated by means of dimensional tests (dimensions, volumetric capacity, weight and thickness), and mechanical tests (dynamic compression and impact resistance) and compared with PP (polypropylene) packaging of the same format. Also, the potential for organoleptic contamination of some food types (margarine, mayonnaise and cream cheese) were investigated. It was concluded that PHB has a different resistance to dynamic compression in relation to PP. This reflects in its deformation value, which is about 50% lower than that of PP, characterizing a more rigid and less flexible material. Under normal freezing and refrigeration conditions the performance of PHB tended to be interior to that of PP, whereas at higher temperatures PHB performed better than PP. Dimensional characterization assay results reinforced the necessity for designing special molds for the injection of PHB or for the optimization of injection conditions and mold temperature. The sensorial results with the foods tested were positive indicating no notable difference at the 5% level. The results showed that there is possibly a future for packaging made from biobased materials such as PHB. (c) 2005 Elsevier Ltd. All rights reserved.