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Filme ativo com extrato de limão na preservação de alimentos suscetíveis de oxidação e contaminação microbiológica
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Resumo(s)
A segurança alimentar é um tema da maior relevância, sendo que um alimento não deverá causar dano ao consumidor. São muitos os desafios nesta matéria, nomeadamente no que diz respeito às embalagens alimentares, aos seus materiais constituintes e à possível migração destes para os alimentos. As embalagens ativas, que interagem deliberadamente com o seu conteúdo, podem retardar ou inibir processos de deterioração dos alimentos, tais como a oxidação lipídica ou o crescimento de microrganismos, permitindo aumentar o tempo de vida útil dos alimentos e garantir a sua segurança alimentar. A deterioração dos alimentos pode ser minimizada, através da adição de antimicrobianos e antioxidantes, naturais ou sintéticos. Os compostos naturais são uma alternativa segura aos sintéticos.
O objetivo deste trabalho foi avaliar a eficácia antioxidante e antimicrobiana de uma embalagem alimentar ativa à base de proteína de soro de leite com incorporação de extrato de limão. Estudou-se a atividade antioxidante do extrato sozinho e quando incorporado no filme ativo. O extrato apresentou boa capacidade antioxidante e elevado conteúdo em compostos fenólicos totais e flavonoides totais, sendo que quando incorporado no filme os valores foram mais baixos. Relativamente à atividade antimicrobiana, o extrato demonstrou capacidade inibitória ao Staphylococcus aureus. Quando incorporado no filme, apresentou atividade antimicrobiana ao Enterococcus faecalis. O alimento escolhido foi a cavala fresca, devido ao elevado teor lipídico e ao curto tempo de vida útil. As fatias de cavala foram embaladas em filme ativo, filme controlo (sem extrato) e saco de plástico estéril, durante 2, 4, 6 e 8 dias. O estado de oxidação lipídica da cavala, após embalamento foi avaliado através do ensaio de TBARS. Os resultados indicaram que o filme ativo tende a retardar a oxidação lipídica da cavala até ao 8º dia. Foi efetuada também uma avaliação microbiológica através das contagens de microrganismos a 30 ºC, de Enterobactereaceae e de Escherichia coli, respetivamente. O filme ativo foi eficaz até ao 4º dia. Os resultados obtidos demonstraram que a incorporação do extrato de limão no filme de proteína de soro de leite, sugere um aumento da capacidade antioxidante e antimicrobiana dos filmes.
Food safety is a topic of the most significant importance, and food should not cause harm to the consumer. There are many challenges in this matter, namely about food packaging, its constituent materials and the possible migration of these to food. Active packaging, which deliberately interacts with its content, can delay or inhibit food spoilage processes, such as lipid oxidation or the growth of microorganisms, allowing to increase in the shelf life of food and guaranteeing its food safety. Food spoilage can be minimized through the addition of natural or synthetic antimicrobials and antioxidants. Natural compounds are a safe alternative to synthetics. This work aimed to evaluate the antioxidant and antimicrobial efficacy of an active food package based on whey protein with the incorporation of lemon extract. The antioxidant activity of the extract alone and when incorporated into the active film was studied. The extract showed good antioxidant capacity and high content of total phenolic compounds and flavonoids; the values were lower when incorporated into the film. The extract showed an inhibitory capacity to Staphylococcus aureus regarding antimicrobial activity. When incorporated into the film, it showed antimicrobial activity against Enterococcus faecalis. The food was fresh mackerel due to its high lipid content and short shelf life. Mackerel slices were packed in active film, control film (without extract) and a sterile plastic bag for 2, 4, 6 and 8 days. The lipid oxidation state of mackerel after packaging was evaluated using the TBARS assay. The results indicated that the active film tends to delay the lipid oxidation of mackerel until the 8th day. A microbiological evaluation was also carried out through the counts of microorganisms at 30 °C of Enterobacteriaceae and Escherichia coli, respectively. The active film was effective until the 4th day. The results showed that the incorporation of lemon extract in the whey protein film suggests an increase in the antioxidant and antimicrobial capacity of the films.
Food safety is a topic of the most significant importance, and food should not cause harm to the consumer. There are many challenges in this matter, namely about food packaging, its constituent materials and the possible migration of these to food. Active packaging, which deliberately interacts with its content, can delay or inhibit food spoilage processes, such as lipid oxidation or the growth of microorganisms, allowing to increase in the shelf life of food and guaranteeing its food safety. Food spoilage can be minimized through the addition of natural or synthetic antimicrobials and antioxidants. Natural compounds are a safe alternative to synthetics. This work aimed to evaluate the antioxidant and antimicrobial efficacy of an active food package based on whey protein with the incorporation of lemon extract. The antioxidant activity of the extract alone and when incorporated into the active film was studied. The extract showed good antioxidant capacity and high content of total phenolic compounds and flavonoids; the values were lower when incorporated into the film. The extract showed an inhibitory capacity to Staphylococcus aureus regarding antimicrobial activity. When incorporated into the film, it showed antimicrobial activity against Enterococcus faecalis. The food was fresh mackerel due to its high lipid content and short shelf life. Mackerel slices were packed in active film, control film (without extract) and a sterile plastic bag for 2, 4, 6 and 8 days. The lipid oxidation state of mackerel after packaging was evaluated using the TBARS assay. The results indicated that the active film tends to delay the lipid oxidation of mackerel until the 8th day. A microbiological evaluation was also carried out through the counts of microorganisms at 30 °C of Enterobacteriaceae and Escherichia coli, respectively. The active film was effective until the 4th day. The results showed that the incorporation of lemon extract in the whey protein film suggests an increase in the antioxidant and antimicrobial capacity of the films.
Descrição
Tese de mestrado, Qualidade Alimentar e Saúde, 2022, Universidade de Lisboa, Faculdade de Farmácia.
Palavras-chave
Embalagem ativa Proteína de soro de leite Extrato de limão Cavala Capacidade antioxidante e antimicrobiana Teses de mestrado - 2022