Preparo e caracterização de filmes nanoestruturados à base de pectina e polpas de frutas com potencial uso como embalagens alimentícias
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Data
2016-10-14
Autores
Melo, Pamela Thais Sousa [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os resíduos gerados pelo descarte de embalagens produzidas por fontes não biodegradáveis vêm crescendo a cada ano e constitui um grande problema do ponto de vista ambiental. Uma das formas encontradas para amenizar o problema consiste no desenvolvimento de embalagens biodegradáveis obtidas através de polímeros naturais. No entanto, estas embalagens apresentam algumas propriedades desfavoráveis, como por exemplo, baixas propriedades de barreira e baixa resistência mecânica, dificultando, assim, sua utilização. Boa parte dos resíduos plásticos gerados é produzida pela indústria de alimentos, o que vem impulsionando pesquisas, principalmente, no desenvolvimento de filmes comestíveis. Vários grupos de polímeros naturais têm sido estudados para a formação dos filmes, dentre eles, os polissacarídeos merecem destaque. Uma das formas reportadas na literatura para melhorar as propriedades de filmes à base de polissacarídeos inclui a adição de nanoestruturas às matrizes poliméricas. O presente trabalho visou à produção de filmes comestíveis baseados em pectina e polpas de frutas. Nanopartículas de quitosana foram sintetizadas e adicionadas às matrizes poliméricas com o objetivo de melhorar as propriedades dos filmes. As nanopartículas apresentaram tamanho médio de 110 nm e potencial zeta em torno de +40 mV. Os filmes foram produzidos por “casting” e apresentaram características satisfatórias, como: manuseabilidade, homogeneidade e continuidade. Através das análises mecânicas - tensão máxima e elongação - foi possível concluir que as nanopartículas atuaram como agentes de reforço, aumentando a tenacidade dos filmes. Testes de permeabilidade ao vapor de água evidenciaram que filmes nanoestruturados apresentaram melhores propriedades de barreira. A distribuição das nanoestruturas nas matrizes poliméricas pôde ser melhor elucidada através de análises de microscopia eletrônica de varredura, que demonstraram uma dispersão homogênea das mesmas ao longo dos filmes. A temperatura de transição vítrea dos filmes não sofreu influência significativa com a adição das nanopartículas. Através de medidas de FT-IR foi possível verificar os deslocamentos das bandas características, sugerindo interações entre a matriz e as nanoestruturas.
The residues generated by the disposal of packaging materials produced by non-biodegradable sources have been growing every year and is a major problem from an environmental point of view. One way to mitigate the problem encountered has been the production of biodegradable packaging materials obtained from natural polymers. However, those materials have some unfavorable properties, such as low barrier properties and low mechanical strength, thus hampering their use. Many of the generated plastic waste is produced by the food industry, which has stimulated research, particularly in the development of edible films. Many groups of natural polymers have been studied for film the formation, among them, the polysaccharides are noteworthy. One possible strategy to improve properties of polysaccharide films is by incorporating nanostructured materials into the polymer matrices. One way reported in the literature involves the addition of chitosan nanoparticles. This paper aimed to the production of biodegradable films based on pectin, fruit pulp and chitosan nanoparticles to evaluate the increase in mechanical and physical properties thereof. Initially, the nanostructures were synthesized and characterized. They showed an average size of 110 nm and zeta potential around +40 mV. Then, films were produced using the casting technique. The films showed satisfactory characteristics, such as manageability, homogeneity and continuity. Through the mechanical analysis - maximum stress and elongation - it was concluded that the nanoparticles served as fillers, increasing the toughness of the films. Water vapor permeability testing showed that nanostructured films showed improved barrier properties. The chemical interactions between nanoparticles and polymer matrices could be better elucidated by analysis of scanning electron microscopy, which showed a homogeneous dispersion of the same over the films. The glass transition temperature of the films was not affected by the addition of nanoparticles. FT-IR spectra indicated the displacement of the characteristic bands, suggesting interactions between the matrix and the nanostructures.
The residues generated by the disposal of packaging materials produced by non-biodegradable sources have been growing every year and is a major problem from an environmental point of view. One way to mitigate the problem encountered has been the production of biodegradable packaging materials obtained from natural polymers. However, those materials have some unfavorable properties, such as low barrier properties and low mechanical strength, thus hampering their use. Many of the generated plastic waste is produced by the food industry, which has stimulated research, particularly in the development of edible films. Many groups of natural polymers have been studied for film the formation, among them, the polysaccharides are noteworthy. One possible strategy to improve properties of polysaccharide films is by incorporating nanostructured materials into the polymer matrices. One way reported in the literature involves the addition of chitosan nanoparticles. This paper aimed to the production of biodegradable films based on pectin, fruit pulp and chitosan nanoparticles to evaluate the increase in mechanical and physical properties thereof. Initially, the nanostructures were synthesized and characterized. They showed an average size of 110 nm and zeta potential around +40 mV. Then, films were produced using the casting technique. The films showed satisfactory characteristics, such as manageability, homogeneity and continuity. Through the mechanical analysis - maximum stress and elongation - it was concluded that the nanoparticles served as fillers, increasing the toughness of the films. Water vapor permeability testing showed that nanostructured films showed improved barrier properties. The chemical interactions between nanoparticles and polymer matrices could be better elucidated by analysis of scanning electron microscopy, which showed a homogeneous dispersion of the same over the films. The glass transition temperature of the films was not affected by the addition of nanoparticles. FT-IR spectra indicated the displacement of the characteristic bands, suggesting interactions between the matrix and the nanostructures.
Descrição
Palavras-chave
Filmes comestíveis, Nanopartículas de quitosana, Pectina, Edible films, Chitosan nanoparticles, Pectin