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Diferentes métodos de secagem e desodorização por fluido supercritico de proteínas miofibrilares de resíduos de peixe para elaboração de filmes biodegradáveis
(Universidade Federal do Pará, 2021-03-16) BATISTA, Jáira Thayse Souza; LOURENÇO, Lúcia de Fátima Henriques; http://lattes.cnpq.br/7365554949786769; https://orcid.org/0000-0001-5009-8235
The present thesis consists of several connected stages and the objectives of each are: a) to study the influence of the use of different types of fish residues for the extraction of myofibrillar proteins (MP) on the technological properties of biodegradable films; b) To study the effect of different drying methods and temperatures of fish MP on the technological properties of the films; c) Deodorize fish MP using extraction with supercritical CO2, compare with solvent extraction in Soxhlet and elaborate biodegradable films with sensory properties suitable for use as food packaging. Based on these objectives, three manuscripts were prepared with the research results. In the first manuscript, carcasses with adhered muscle were used to obtain the mechanically separated meat (MSM) and the fillet toilet parings. The MP were extracted from these residues and the films produced. The results showed that the type of waste used directly influences all the analyzed properties of the films, due to the different centesimal compositions of the MP of the MSM and of the parings with significant differences mainly in the content of lipids and ash. These non-protein compounds in the protein extracted from the MSM acted as an interference in the formation of the film, generating inferior technological and thermal properties when compared to the film produced with MP extracted from the parings. Increasing the number of washes in the extraction of MP from more fatty and pigmented residues could decrease the concentration of non-protein compounds. In the second manuscript, the MP were dried by lyophilization at -60 ° C for 48 h and by convective drying of hot air at 40 °C, 60 °C at 80 °C. In convection drying, drying curves were constructed and the adjustments of the mathematical models were evaluated. The films were produced with dried proteins in different conditions and characterized. The drying times found were 540 min (40 °C), 300 min (60 °C) and 120 min (80 °C). The "logarithmic" models followed by the "diffusion approach" were the ones that best adjusted to all temperatures. The results of protein electrophoresis and the characterization of the film showed that the convective drying caused changes in the three-dimensional structure of MP, favoring the formation of a highly reticulated protein network with numerous hydrogen, hydrophobic and disulfide bonds, generating films with equal or better properties than those made with lyophilized MP. It was possible to verify that the convection drying by hot air can be used efficiently in MP used in the production of biodegradable films, reducing the time and the cost of producing the films. In the third manuscript, to deodorize the MP, supercritical CO2 was used, with global yield isotherms built at 40 and 60 ºC at 200, 300 and 400 bar. In solvent extraction in Soxhlet, petroleum ether was used at 52 ° C for 2h 30 min. The filmswere produced with MP control without deodorization and with MP deodorized with solvent in Soxhlet (due to the limitations caused by the pandemic caused by the new corona virus (SARS-CoV-2), until now it was not possible to define the best condition of deodorization with supercritical CO2 and make the film with MP deodorized by this method). The results showed that the best operational condition with supercritical CO2 was 40 ° C / 200 bar with a yield of 5.06 b.s. The best condition for supercritical extraction considering the greater efficiency in removing fish odor has not yet been determined due to the lack of analysis of aromatic compounds, it is not possible to say whether the higher oil extraction yield is directly related to greater extraction of oil other aromatic compounds such as trimethylamine and dimethylamine disulfide. The yield in relation to oil extraction was higher in solvent extraction in Soxhlet (8.04 b.s), possibly due to the low selectivity of the organic solvent that can also extract other compounds compared to the highly selective supercritical CO2. The film produced with MP that underwent solvent deodorization in Soxhlet showed all the studied properties improved in relation to the control. This indicates that the removal of lipids can solve not only the problem with the odor of fish in the films, but also provide a more isolated protein without interferences that favor the formation of films with better properties.