This research aimed to assess the properties of biodegradable films prepared with lyophilized myofibrillar proteins (LMP) from fish filleting residues, fatty acids (stearic, palmitic, and caproic), and surfactant (SLS). The films were characterized to assess the effects of adding those components. Adding fatty acids and SLS resulted in more flexible films with higher elongation values compared to the LMP film. The films prepared with 5% stearic acid and 10% SLS and with 10% palmitic acid and 20% SLS had higher tensile strength compared to the LMP film. Solubility reached 100% in the films added with 10% fatty acids with and without SLS. Oncreasing the concentration of fatty acids and SLS led to less transparent films. Microscopy analysis showed changes in the morphological structure of the films added with fatty acids and SLS, resulting in whitish films when greater SLS contents were used.

The bioconversion of protein from the fishing industry waste into bioplastics allows the valorization of biological material, reducing the production of waste and consequently of negative environmental impacts through the use of synthetic packaging. The objective of this work was to develop biodegradable films from the mixture of gelatin and myofibrillar fish proteins. Proteins (myofibrillar and gelatin) were extracted from filleting residues from king weakfish (Macrodon ancylodon) from industrial fishing. The properties of the blend films were compared to those of individual protein films. It was found by scanning electron microscopy that there was good compatibility between the two polymers. Mechanical analyzes showed that myofibrillar proteins films were the most resistant to traction, but less flexible; characteristics contrary to those of gelatin. The mixing films presented the lowest values of water vapor permeability and solubility were transparent, and mechanically strong and flexible, confirming the improvement of the properties by mixing the polymers. Fourier transform infrared spectroscopy revealed that there was interaction between the myofibrillar protein chains and gelatine driven by hydrogen bonds, thus forming cohesive and reinforced matrix, which resulted in good thermal resistance of the films. The mixture between polymers improved the technological properties of the elaborated biodegradable films, making its application feasible as food packaging.

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O objetivo deste trabalho foi desenvolver e caracterizar filmes biodegradáveis de proteínas miofibrilares de aparas da filetagem da corvina (Micropogonias furnieri) utilizando ácido esteárico (AE) para melhorar suas propriedades tecnológicas. As proteínas extraídas foram liofilizadas, caracterizadas e utilizadas na elaboração dos filmes. As soluções filmogênicas foram secas em suporte de silicone a 35°C por 14 horas em estufa incubadora, de acordo com o método casting. A região com as melhores propriedades mecânicas, físicas e de barreira dos filmes foi definida por planejamento fatorial completo. As proteínas miofibrilares liofilizadas (PML) apresentaram teor proteico de 96,03%. A análise dos resultados do planejamento experimental indicou que as melhores condições para elaborar o filme otimizado foram: 2,84% PML, 3,18% AE e 78,41% SDS (dodecil sulfato de sódio). Os filmes controles foram elaborados com 2,84% de PML e 30% de plastificante. O filme otimizado apresentou significativa diminuição da permeabilidade ao vapor de água (5,87E-11 g m m-² s-¹ Pa-¹), com maior resistência a tração (6,35 MPa) e menor elongação (235,60%) quando comparado ao controle (p ≤ 0,05. Apresentando também menores valores de transparência e excelente propriedade de barreira UV, indicando tendência ao opaco. Apresentou boa estabilidade térmica e a microestrutura revelou mudança estrutural na matriz filmogênica, confirmado pela difração de raio-x, indicando a influência do SDS e AE na cristalinidade do filme. Houve aumento de 22% na solubilidade e ligeira diminuição do intumescimento do filme otimizado em relação ao controle. Os resultados obtidos representam contribuição positiva com o aproveitamento de subprodutos de peixe aplicando tecnologias alternativas e sustentáveis.