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Authors
Abstract(s)
Em resposta à crescente preocupação ambiental no que concerne ao elevado consumo de plásticos
derivados do petróleo, como embalagens alimentares, a procura por alternativas sustentáveis,
como a utilização de biopolímeros como substitutos dos plásticos sintéticos em embalagens,
ganhou destaque. A pululana, produzida pelo fungo Aureobasidium pullulans, é considerada uma
alternativa promissora aos plásticos sintéticos e tem despertado um crescente interesse na
produção de filmes comestíveis para potenciais embalagens alimentares ativas. Os óleos
essenciais (OEs) destacam-se como agentes antioxidantes e antimicrobianos naturais,
contribuindo para minimizar os impactos negativos dos resíduos químicos nos alimentos, na
saúde humana e no meio ambiente, enquanto prolongam o tempo de prateleira dos produtos. Um
exemplo é o OE de lavandim, extraído da espécie Lavandula hybrida, cujas propriedades
aromáticas e medicinais são idênticas às do OE de lavanda, mas têm efeitos mais rápidos e
intensos. Apesar de todas as vantagens que os OEs e os seus compostos bioativos possuem, a sua
aplicação ainda e´ limitada devido a desvantagens como a sua volatilidade e instabilidade. Uma
estratégia possível para combater estas desvantagens e´ o seu encapsulamento. Este trabalho teve
como principal objetivo a encapsulação do OE de lavandim e a sua incorporação em filmes de
pululana, conferindo-lhes propriedades bioativas, para aplicação na indústria alimentar, como
embalagens ativas. Inicialmente, o OE de lavandim foi analisado, revelando fortes propriedades
antioxidantes e antimicrobianas contra vários patoge´neos alimentares. Utilizou-se o método de
emulsão e evaporação do solvente para preparar cápsulas de ácido polilático (PLA) e encapsular
o OE de lavandim. Foram preparadas cápsulas com e sem OE, tendo sido confirmada a sua
estrutura física e química por SEM, FTIR e DSC. Para as amostras sem OE, obtiveram-se esferas
com 0,585 ±0,067 µm de diâmetro, enquanto para as amostras com OE, obtiveram-se esferas
maiores com 1,242 ±0,138 µm de diâmetro. Foram então produzidos quatro tipos de filmes:
pululana, pululana com OE de lavandim e pululana + cápsulas, com e sem OE; em todos eles a
pululana foi dissolvida em água, com adição de glicerol como plastificante. Ao analisar as
propriedades bioativas dos filmes, estes revelaram-se potenciais materiais para embalagens
alimentares inibindo a oxidação e peroxidação lipídica. Os filmes de pululana com OE de
lavandim e de pululana + cápsulas c/ OE apresentaram ainda uma percentagem de inibição de
cerca de 51 % no ensaio de sequestração de radicais livres DPPH. Já no ensaio de difusão em disco,
ocorreu inibição do crescimento bacteriano nos filmes de pululana e nos filmes de pululana com
OE, especificamente nas bactérias Gram-positivas (L. monocytogenes e S. aureus) e registaramse ainda inibições por contacto para os filmes de pululana com OE (E. coli) e de pululana +
cápsulas com OE (P. aeruginosa). A incorporação do OE de lavandim melhorou as propriedades
de superfície dos filmes de pululana devido à hidrofobicidade do OE e estes filmes revelaram ser
transparentes e com uma cor amarelada. Já a adição do OE encapsulado, aumentou a gramagem
e espessura dos filmes, aumentando a permeabilidade e a opacidade destes. O OE encapsulado
demonstrou melhorar as propriedades mecânicas, tornando-os mais dúcteis e menos rígidos.
Estes filmes biocompósitos de pululana com OE de lavandim encapsulado apresentam-se como uma alternativa promissora e ecológica para embalagens alimentares, contribuindo para a
redução do uso de plásticos convencionais derivados do petróleo.
In response to the growing environmental concern over the extensive use of petroleum-derived plastics in food packaging, the search for sustainable alternatives, such as the use of biopolymers as substitutes for synthetic plastics in packaging, has gained prominence. Pullulan, produced by the fungus Aureobasidium pullulans, is considered a promising alternative to synthetic plastics and has attracted increasing interest in producing edible films for potential active food packaging. Moreover, considering public saturation with chemical and synthetic additives, essential oils (EOs) emerge as natural antioxidant and antimicrobial agents, contributing to mitigate the negative impacts of chemical residues on food, human health, and the environment, while extending the product shelf-life. An example is lavandin EO, extracted from Lavandula hybrida, whose aromatic and medicinal properties are identical to those of lavender EO but exhibit faster and more intense effects. Despite the advantages offered by the EOs and their bioactive compounds, their application is limited by disadvantages like hydrophobicity, volatility, and instability. One possible strategy to overcome these limitations is their encapsulation. This work primarily aimed to encapsulate lavandin EO and incorporate it into pullulan films, giving them bioactive properties for application in the food industry, as active packaging. Lavandin EO was initially analyzed, revealing strong antioxidant and antimicrobial properties against several foodborne pathogens. The emulsion and solvent evaporation method was employed to prepare polylactic acid (PLA) capsules for encapsulating lavandin EO. Capsules were produced with and without EO, and their physical and chemical structure was confirmed by SEM, FTIR, and DSC. For samples without lavandin EO spheres with a diameter of 0.585 ± 0.067 µm were obtained, whereas for samples with EO, larger spheres with a diameter of 1.242 ± 0.138 µm were obtained. Subsequently, pullulan films containing glycerol as a plasticizer were developed, resulting in four types of films: pullulan, pullulan with EO, pullulan + capsules, with and without EO. Significant roughness was observed in the pullulan + capsules films due to the dimensions of the incorporated capsules. Finally, the resulting films were evaluated for their bioactive, thermal, structural, mechanical, surface, barrier, and optical properties. When analyzing the bioactive properties of the films, they proved to be potential materials for food packaging, inhibiting lipid oxidation and peroxidation. The pullulan films with lavandin EO and pullulan + capsules with EO films also exhibited a inhibition rate of approximately 51% in the DPPH free radical scavenging assay. In the disk diffusion assay, bacterial growth inhibition was observed in the pullulan films and pullulan with EO films, particularly in Gram-positive bacteria (L. monocytogenes and S. aureus). Contact inhibitions were also observed for pullulan with EO films (E. coli) and pullulan + capsules with EO films (P. aeruginosa). The incorporation of lavandin EO improved the surface properties of pullulan films due to the hydrophobic nature of the EO. These films were found to be transparent with a yellowish color. On the other hand, the addition of encapsulated EO increased the weight and thickness of the films, leading to increased permeability and opacity. The encapsulated EO also showed an improvement in mechanical properties, making them more ductile and less rigid. These biocomposite films of pullulan with encapsulated lavandin EO present a promising and ecological alternative for food packaging, contributing to the reduction of conventional petroleum-derived plastics usage.
In response to the growing environmental concern over the extensive use of petroleum-derived plastics in food packaging, the search for sustainable alternatives, such as the use of biopolymers as substitutes for synthetic plastics in packaging, has gained prominence. Pullulan, produced by the fungus Aureobasidium pullulans, is considered a promising alternative to synthetic plastics and has attracted increasing interest in producing edible films for potential active food packaging. Moreover, considering public saturation with chemical and synthetic additives, essential oils (EOs) emerge as natural antioxidant and antimicrobial agents, contributing to mitigate the negative impacts of chemical residues on food, human health, and the environment, while extending the product shelf-life. An example is lavandin EO, extracted from Lavandula hybrida, whose aromatic and medicinal properties are identical to those of lavender EO but exhibit faster and more intense effects. Despite the advantages offered by the EOs and their bioactive compounds, their application is limited by disadvantages like hydrophobicity, volatility, and instability. One possible strategy to overcome these limitations is their encapsulation. This work primarily aimed to encapsulate lavandin EO and incorporate it into pullulan films, giving them bioactive properties for application in the food industry, as active packaging. Lavandin EO was initially analyzed, revealing strong antioxidant and antimicrobial properties against several foodborne pathogens. The emulsion and solvent evaporation method was employed to prepare polylactic acid (PLA) capsules for encapsulating lavandin EO. Capsules were produced with and without EO, and their physical and chemical structure was confirmed by SEM, FTIR, and DSC. For samples without lavandin EO spheres with a diameter of 0.585 ± 0.067 µm were obtained, whereas for samples with EO, larger spheres with a diameter of 1.242 ± 0.138 µm were obtained. Subsequently, pullulan films containing glycerol as a plasticizer were developed, resulting in four types of films: pullulan, pullulan with EO, pullulan + capsules, with and without EO. Significant roughness was observed in the pullulan + capsules films due to the dimensions of the incorporated capsules. Finally, the resulting films were evaluated for their bioactive, thermal, structural, mechanical, surface, barrier, and optical properties. When analyzing the bioactive properties of the films, they proved to be potential materials for food packaging, inhibiting lipid oxidation and peroxidation. The pullulan films with lavandin EO and pullulan + capsules with EO films also exhibited a inhibition rate of approximately 51% in the DPPH free radical scavenging assay. In the disk diffusion assay, bacterial growth inhibition was observed in the pullulan films and pullulan with EO films, particularly in Gram-positive bacteria (L. monocytogenes and S. aureus). Contact inhibitions were also observed for pullulan with EO films (E. coli) and pullulan + capsules with EO films (P. aeruginosa). The incorporation of lavandin EO improved the surface properties of pullulan films due to the hydrophobic nature of the EO. These films were found to be transparent with a yellowish color. On the other hand, the addition of encapsulated EO increased the weight and thickness of the films, leading to increased permeability and opacity. The encapsulated EO also showed an improvement in mechanical properties, making them more ductile and less rigid. These biocomposite films of pullulan with encapsulated lavandin EO present a promising and ecological alternative for food packaging, contributing to the reduction of conventional petroleum-derived plastics usage.
Description
Keywords
Embalagens Ativas Encapsulamento Lavandim Lavandula Hybrida Óleo Essencial Pululana