Dados do Trabalho

Título

BILAYER FILMS BASED ON PHBV AND PROTEINS CONTAINING RUTIN AND CARVACROL IN PICKERING EMULSION

Introdução

Protein-based films have low water vapor barrier properties due to their hydrophilic nature but high oxygen barrier capacity. One strategy to improve the performance of these monolayer films is the development of bilayers with complementary properties. For example, Poly(3-hydroxybutyrate-co-3hydroxyvalerate) (PHBV) is a thermoplastic and biodegradable polyester exhibiting opposite barrier properties to proteins-based films. On the other hand, the incorporation of active agents (antimicrobial and/or antioxidant) allows obtaining bilayers with extra functional properties than conventional packaging materials. The objective of this study was to obtain and characterize active bilayer films based on PHBV and gelatin or sodium caseinate monolayers incorporating rutin and carvacrol in Pickering emulsion (PE).

Material e Métodos

The protein-based film was obtained by casting while the PHBV films and the assembly of the bilayers were carried out by thermocompression. The barrier, optical and mechanical properties of the monolayers and bilayers containing or not the PE were determined

Resultados e Discussão

In general, the incorporation of phenols (rutin and carvacrol) in the monolayers improved their water barrier capacities (lower WVP and OP values) while increasing their resistance to break, surely because a crosslinking effect. This trend was marked in gelatin-based films than in caseinate monolayers, being less remarkable in the bilayers. The incorporation of the PE into mono and bilayers also affected the gloss and clarity of the films, which were reduced as consequence of the presence of irregularities (droplets) in the surface of the films. As expected, the bilayers exhibited optimal barrier properties as they showed the same WVP and significantly lower OP values (p<0.05) than the PHBV film. In addition, the mechanical behaviour of the bi-layers was intermediate to that found in the mono-layers

Conclusão

The PHBV-gelatin bilayer incorporating the active agents (rutin and carvacrol) exhibited the best barrier properties, being more rigid and less stretchable than the active PHBV-caseinate- films, so being promising films to be used for food packaging applications. Future work will focus on the effect of material migration on the sensory aspects of food.