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Utilização de películas incorporadas com extrato de própolis na conservação de bifes de frango embalados a vácuo e refrigerados
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O própolis é uma substância resinosa produzida por abelhas da espécie Apis mellifera L., utilizada na construção e defesa da colmeia. Apresenta diversas colorações (verde, vermelha, amarela ou acastanhada) e resulta da recolha de exsudatos de flores, botões de folhas e secreções de várias espécies botânicas. Na Europa, as principais fontes incluem resinas de choupo, bétula, pinheiro, amieiro, salgueiro, acácia e carvalho. As propriedades antimicrobianas e antioxidantes do própolis, aliadas à sua segurança como substância natural, conferem-lhe elevado potencial para aplicação na indústria alimentar, nomeadamente como agente de bio preservação. Neste contexto, o presente trabalho teve como objetivo avaliar o potencial do própolis proveniente da região de Trás-os-Montes como conservante natural e ingrediente funcional na preservação de bifes de frango embalados a vácuo, valorizando simultaneamente os produtos apícolas locais.
O extrato etanólico de própolis foi caracterizado, apresentando um teor de compostos fenólicos totais de 391,68 ± 6,11 mg EAG/g e de flavonoides totais de 107,99 ± 3,01 mg EQ/g, revelando elevada atividade antioxidante (ensaio DPPH) e atividade antimicrobiana contra Cândida albicans, Staphylococcus aureus e Escherichia coli, confirmando o seu potencial bioativo.
O extrato foi incorporado em películas de hidroxipropilmetilcelulose (HPMC) em diferentes concentrações (0 %, 2 % e 4 %) e aplicado como revestimento sobre bifes de frango embalados a vácuo. As análises físico-químicas e microbiológicas, foram realizadas ao longo dos dias de armazenamento (T0, T3 e T6). Ao nível da cor, verificou-se que as formulações contendo própolis apresentaram maior estabilidade cromática, mantendo valores mais consistentes de L*, a*, b*, C* e hº. Esses resultados indicam menor oxidação e melhor preservação do aspeto visual. As análises microbiológicas evidenciaram reduções significativas nas contagens de mesófilos totais, coliformes, E. coli, bolores e leveduras, e não tendo sido detetados patogénicos como S. aureus ou Listéria monocytogenes, confirmou-se a eficácia antimicrobiana do sistema ativo.
As películas de HPMC enriquecidas com própolis demonstraram ação antioxidante e antimicrobiana, contribuindo para a preservação e segurança dos bifes de frango durante o armazenamento.
Propolis is a resinous substance produced by Apis mellifera L. bees and used in hive construction and defense. Its color may vary (green, red, yellow, or brownish), and it results from the collection of exudates from flowers, leaf buds, and secretions of various botanical species. In Europe, its main sources include resins from poplar, birch, pine, alder, willow, acacia, and oak. The antimicrobial and antioxidant properties of propolis, combined with its safety as a natural compound, confer high potential for its application in the food industry, particularly as a bio preservation agent. In this context, the presente study aimed to evaluate the potential of propolis from the Trás-os-Montes region as a natural preservative and functional ingredient in the preservation of vacuum-packed chicken steaks, while simultaneously valorizing local beekeeping products. The ethanolic extract of propolis was characterized and showed a total phenolic contente of 391.68 ± 6.11 mg EAG/g and a total flavonoid content of 107.99 ± 3.01 mg QE/g, exhibiting strong antioxidant activity (DPPH assay) and antimicrobial activity against Candida albicans, Staphylococcus aureus, and Escherichia coli, confirming its bioactive potential. The extract was incorporated into hydroxypropyl methylcellulose (HPMC) films at different concentrations (0%, 2%, and 4%) and applied as a coating on vacuum-packed chicken steaks. Physico-chemical and microbiological analyses were carried out throughout the storage period (T0, T3 and T6). In terms of colour, the formulations containing propolis were found to show greater chromatic stability, maintaining more consistent L*, a*, b*, C* and hº values. These results suggest reduced oxidation and improved preservation of the product's appearance. Microbiological analyses revealed significant reductions in total mesophiles, coliforms, E. coli, molds, and yeasts, and the absence of pathogens such as S. aureus and Listeria monocytogenes, confirming the antimicrobial efficacy of the active system. HPMC films enriched with propolis demonstrated antioxidant and antimicrobial activity, contributing to the preservation and safety of chicken steaks during storage.
Propolis is a resinous substance produced by Apis mellifera L. bees and used in hive construction and defense. Its color may vary (green, red, yellow, or brownish), and it results from the collection of exudates from flowers, leaf buds, and secretions of various botanical species. In Europe, its main sources include resins from poplar, birch, pine, alder, willow, acacia, and oak. The antimicrobial and antioxidant properties of propolis, combined with its safety as a natural compound, confer high potential for its application in the food industry, particularly as a bio preservation agent. In this context, the presente study aimed to evaluate the potential of propolis from the Trás-os-Montes region as a natural preservative and functional ingredient in the preservation of vacuum-packed chicken steaks, while simultaneously valorizing local beekeeping products. The ethanolic extract of propolis was characterized and showed a total phenolic contente of 391.68 ± 6.11 mg EAG/g and a total flavonoid content of 107.99 ± 3.01 mg QE/g, exhibiting strong antioxidant activity (DPPH assay) and antimicrobial activity against Candida albicans, Staphylococcus aureus, and Escherichia coli, confirming its bioactive potential. The extract was incorporated into hydroxypropyl methylcellulose (HPMC) films at different concentrations (0%, 2%, and 4%) and applied as a coating on vacuum-packed chicken steaks. Physico-chemical and microbiological analyses were carried out throughout the storage period (T0, T3 and T6). In terms of colour, the formulations containing propolis were found to show greater chromatic stability, maintaining more consistent L*, a*, b*, C* and hº values. These results suggest reduced oxidation and improved preservation of the product's appearance. Microbiological analyses revealed significant reductions in total mesophiles, coliforms, E. coli, molds, and yeasts, and the absence of pathogens such as S. aureus and Listeria monocytogenes, confirming the antimicrobial efficacy of the active system. HPMC films enriched with propolis demonstrated antioxidant and antimicrobial activity, contributing to the preservation and safety of chicken steaks during storage.
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Própolis Antioxidante Antimicrobiano Enriquecidas HPMC Bio preservação Carne de frango