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Aproveitamento e Valorização de Polvo da Costa Portuguesa e de Robalo de Aquacultura
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Orientador(es)
Resumo(s)
Os hábitos alimentares dos consumidores têm mudado, sendo os produtos prontos a consumir ou a cozinhar cada vez mais preferidos. Por outro lado, alguns industriais da restauração e catering solicitam matérias primas mais convenientes (sobretudo filetes) com tempos de vida útil mais prolongados. No sentido de dar resposta a estas solicitações procedeu-se à cozedura industrial do polvo comum (Octopus vulgaris) da costa portuguesa, à caraterização nutricional e à avaliação do seu potencial para confecionar pratos à base de polvo e, ainda, ao estudo do impacto da congelação e armazenagem em congelado na qualidade. Para aumentar o tempo de vida útil em refrigerado e em congelado de filetes de peixe, usaram-se filetes de robalo (Dicentrarchus labrax) de aquacultura como modelo, e foram escolhidos, com base na literatura, dois potenciais revestimentos, o iota carragenato e o quitosano.
Os resultados obtidos permitiram concluir que o polvo cozido ultracongelado é um produto conveniente pronto a consumir ou para confeções posteriores, proporciona uma excelente contribuição nutricional para uma dieta alimentar equilibrada e apresenta uma grande estabilidade durante a armazenagem em congelado até pelo menos oito meses. Relativamente aos revestimentos foi selecionado o quitosano (soluções a 1,0% e tempos de imersão de 10 segundos) por proporcionar uma melhor aderência, aspeto uniforme e homogéneo e ausência de cheiro. Os resultados da avaliação sensorial, físico-química e microbiológica indicaram que a estabilidade em refrigerado não foi melhorada, muito embora alguma literatura refira efeitos significativos. Relativamente aos filetes armazenados em congelado observaram-se alguns aspetos positivos ao longo de catorze meses de armazenagem devidos ao revestimento, nomeadamente na capacidade de retenção da água e nas contagens microbiológicas totais, pelo que a substituição da água de vidragem por este revestimento poderá vir a ter algum potencial uma vez que poderá contribuir para gastar menores quantidade de água e energia associadas à operação de vidragem.
The behaviours of consumers towards food have changed in last years, with products ready to eat or ready to cook increasingly preferred. On the other hand, some food and catering producers request more convenient raw materials (especially fillets) with longer shelf life. In order to answer to these requirements, studies on industrial cooking of common octopus (Octopus vulgaris) caught off the Portuguese coast, nutritional characterization and the evaluation of its potential for making dishes based on cooked octopus and, still, the study of the impact of deep freezing and frozen storage quality were carried out. To increase the shelf life of chilled and frozen fish fillets, sea bass fillets (Dicentrarchus labrax) were used as a model, and two potential coatings, iota carrageenan and chitosan, were chosen, based on the literature search. The results obtained allowed us to conclude that the deep-frozen cooked octopus is a convenient product ready for consumption or for further meal´s preparations, provides an excellent nutritional contribution to a balanced diet and presented great stability during frozen storage, for at least eight months. Regarding coatings, chitosan (1.0% solutions and immersion times of 10 seconds) was selected since it offers better adhesion, uniform and homogeneous appearance and absence of smell. The results of sensory, physical-chemical, and microbiological evaluations indicated that the cold storage stability was not improved, although several scientific papers have indicated significant effects in shelf-life extension. Regarding the frozen storage stability, some positive aspects were observed for fourteen months due to the coating, namely in the water holding capacity and in the total microbiological counts, so the replacement of the glaze water by this coating may have some potential as it may contribute to spend less water and energy associated to the glazing operation.
The behaviours of consumers towards food have changed in last years, with products ready to eat or ready to cook increasingly preferred. On the other hand, some food and catering producers request more convenient raw materials (especially fillets) with longer shelf life. In order to answer to these requirements, studies on industrial cooking of common octopus (Octopus vulgaris) caught off the Portuguese coast, nutritional characterization and the evaluation of its potential for making dishes based on cooked octopus and, still, the study of the impact of deep freezing and frozen storage quality were carried out. To increase the shelf life of chilled and frozen fish fillets, sea bass fillets (Dicentrarchus labrax) were used as a model, and two potential coatings, iota carrageenan and chitosan, were chosen, based on the literature search. The results obtained allowed us to conclude that the deep-frozen cooked octopus is a convenient product ready for consumption or for further meal´s preparations, provides an excellent nutritional contribution to a balanced diet and presented great stability during frozen storage, for at least eight months. Regarding coatings, chitosan (1.0% solutions and immersion times of 10 seconds) was selected since it offers better adhesion, uniform and homogeneous appearance and absence of smell. The results of sensory, physical-chemical, and microbiological evaluations indicated that the cold storage stability was not improved, although several scientific papers have indicated significant effects in shelf-life extension. Regarding the frozen storage stability, some positive aspects were observed for fourteen months due to the coating, namely in the water holding capacity and in the total microbiological counts, so the replacement of the glaze water by this coating may have some potential as it may contribute to spend less water and energy associated to the glazing operation.
Descrição
Palavras-chave
Pescado Polvo Robalo Tempo de vida útil em refrigerado Estabilidade em congelado Quitosano