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Abstract(s)
Campylobacter coli e Campylobacter jejuni são os principais agentes infeciosos causadores de doença gastrointestinal no mundo. Nos humanos, a principal via de contaminação é o manuseamento, a preparação e o consumo de carne de aves contaminada, sobretudo a carne de frango. As embalagens antimicrobianas são uma forma de embalagens ativas, que permitem a redução e inibição do crescimento de microrganismos que possam estar presentes nos alimentos ou no próprio material das embalagens. Os derivados de celulose são uma fonte importante de biomateriais para a formação de filmes antimicrobianos (AM) e a incorporação de compostos fenólicos nestes filmes, tem vindo a demonstrar grandes potencialidades. O resveratrol (RV) é um composto fenólico de origem natural que apresenta diversas propriedades benéficas para a saúde humana, incluindo propriedades antimicrobianas. No entanto a sua baixa solubilidade em meio aquoso e a sua baixa disponibilidade limitam a sua aplicação. Para ultrapassar estas limitações é feita a sua complexação com ciclodextrinas. Neste trabalho foram desenvolvidos filmes AM em monocamada baseados em carboximetilcelulose (CMC), e em bicamada baseados em acetato de celulose e hidroxietilcelulose. Como agente AM foi incorporado o RV e o seu complexo de inclusão com a hidroxipropil-?-ciclodextrina (HP-?-CD). Foram avaliadas as propriedades físicas destes filmes e a atividade antimicrobiana contra C. coli e C. jejuni pelo método de difusão em disco. Também foi quantificada a percentagem de libertação dos agentes AM em estudo nos filmes em bicamada para etanol a 10%. Como a regulação e a inibição de patogéneos alimentares pode ser regulada por fenómenos de quorum sensing (QS), foi estudada a interferência dos filmes com incorporação de RV e da sua forma complexada nesse processo de comunicação. Foi ainda avaliada a atividade anti-Campylobacter dos filmes em bicamada aplicados num modelo alimentar, usando para este efeito a carne de frango. Os resultados demonstraram que ambos os agentes AM tornaram os filmes de CMC e os filmes em bicamada mais elásticos e menos resistentes. Os filmes em bicamada com incorporação do complexo de inclusão de RV foram os mais hidrofílicos, comparativamente com os de RV na forma livre e o controlo. Os ensaios de libertação demonstraram que os agentes AM foram totalmente libertados dos filmes em bicamada, ao fim de 10 dias à temperatura de 4 e 20ºC. Também foi demonstrado que os filmes em bicamada inibiram o crescimento das estirpes testadas na área de contacto dos filmes com a superfície de agar e formaram um halo de inibição, enquanto os filmes de CMC apenas inibiram o crescimento na zona de contacto. Mostrou-se que os filmes em bicamada possuíram atividade anti-QS através da inibição da produção de violaceína superior a 70%. Por fim, foi observada uma redução das Unidades Formadoras de Colónias de C. coli e C. jejuni, dependente da temperatura de incubação, por ação dos filmes em bicamada testados no peito de frango. Em suma, este estudo demonstrou o elevado potencial dos filmes AM biodegradáveis com incorporação de RV e da sua forma complexada com HP-?-CD no controlo de Campylobacter em carne de frango.
Campylobacter coli and Campylobacter jejuni are among the biggest worldwide causes of human bacterial gastroenteritis. The source of human infection is mainly associated with handling, preparation and consumption of contaminated poultry meat, mainly chicken meat. Antimicrobial packaging is one of the types of active packaging that allows to reduce and to inhibit the microbial growth already contained in the food or in the packaging material itself. Cellulose derivatives are an important source of biomaterials for the preparation of antimicrobial (AM) films and the incorporation of phenolic compounds in those films has demonstrated great antimicrobial potential. Resveratrol (RV) is a phenolic compound of natural origin with several beneficial properties for human health, including antimicrobial properties. However, its low solubility in aqueous media and its low stability limit its potential applications. To overcome these drawbacks it is commonly complexed with cyclodextrins. In this work it was developed an AM monolayer film based on carboxymethylcellulose (CMC), and a bilayer one based on cellulose acetate and hydroxyethylcellulose. As AM agent, it was incorporated RV and RV complexed with hydroxypropyl-?-cyclodextrin (HP-?-CD). The physical properties of these films and its antimicrobial activity against C. coli and C. jejuni were evaluated by the disk diffusion method. The release percentage of the AM agents in bilayer films for 10% ethanol was also quantified. Being the regulation and the inhibition of foodborne pathogens regulated by quorum sensing phenomena, the impact of the films which was incorporated with RV and its complex form in this communication process was studied. It was also evaluated the anti-Campylobacter activity of the bilayer films applied in a food model, using for this purpose chicken meat. The results showed that the CMC and bilayer films with both AM agents become more elastic and less resistant. The bilayer films incorporated with RV inclusion complex were more hydrophilic when compared with the ones with RV in its pure form and with the control film. The release tests showed that the AM agents were totally released from the bilayer films after 10 days at 4 and 20ºC. It was also shown that the bilayer films inhibited the growth of the tested strains in the contact area of the films with the agar surface and formed an inhibition zone, while the CMC films only inhibited the growth in the contact area. It was shown that the bilayer films had anti-QS activity demonstrated by the inhibition of the violacein production by more than 70%. Finally, when the bilayer films were tested in the chicken breast it was observed that Colonies Forming Units reduction of C. jejuni and C. coli was dependent on the incubation temperature. In sum, this study demonstrated the high potential of biodegradable AM films with the incorporation of RV and its inclusion complex with HP-?-CD for the control of Campylobacter in chicken meat.
Campylobacter coli and Campylobacter jejuni are among the biggest worldwide causes of human bacterial gastroenteritis. The source of human infection is mainly associated with handling, preparation and consumption of contaminated poultry meat, mainly chicken meat. Antimicrobial packaging is one of the types of active packaging that allows to reduce and to inhibit the microbial growth already contained in the food or in the packaging material itself. Cellulose derivatives are an important source of biomaterials for the preparation of antimicrobial (AM) films and the incorporation of phenolic compounds in those films has demonstrated great antimicrobial potential. Resveratrol (RV) is a phenolic compound of natural origin with several beneficial properties for human health, including antimicrobial properties. However, its low solubility in aqueous media and its low stability limit its potential applications. To overcome these drawbacks it is commonly complexed with cyclodextrins. In this work it was developed an AM monolayer film based on carboxymethylcellulose (CMC), and a bilayer one based on cellulose acetate and hydroxyethylcellulose. As AM agent, it was incorporated RV and RV complexed with hydroxypropyl-?-cyclodextrin (HP-?-CD). The physical properties of these films and its antimicrobial activity against C. coli and C. jejuni were evaluated by the disk diffusion method. The release percentage of the AM agents in bilayer films for 10% ethanol was also quantified. Being the regulation and the inhibition of foodborne pathogens regulated by quorum sensing phenomena, the impact of the films which was incorporated with RV and its complex form in this communication process was studied. It was also evaluated the anti-Campylobacter activity of the bilayer films applied in a food model, using for this purpose chicken meat. The results showed that the CMC and bilayer films with both AM agents become more elastic and less resistant. The bilayer films incorporated with RV inclusion complex were more hydrophilic when compared with the ones with RV in its pure form and with the control film. The release tests showed that the AM agents were totally released from the bilayer films after 10 days at 4 and 20ºC. It was also shown that the bilayer films inhibited the growth of the tested strains in the contact area of the films with the agar surface and formed an inhibition zone, while the CMC films only inhibited the growth in the contact area. It was shown that the bilayer films had anti-QS activity demonstrated by the inhibition of the violacein production by more than 70%. Finally, when the bilayer films were tested in the chicken breast it was observed that Colonies Forming Units reduction of C. jejuni and C. coli was dependent on the incubation temperature. In sum, this study demonstrated the high potential of biodegradable AM films with the incorporation of RV and its inclusion complex with HP-?-CD for the control of Campylobacter in chicken meat.
Description
Keywords
Campylobacter Complexo de Inclusão de Resveratrol Derivados de Celulose Filmes Antimicrobianos Resveratrol