Navegando por Assunto "Myofibrillar proteins"

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Acesso aberto (Open Access)
Adição de ácido esteárico e surfactante em filmes elaborados com proteínas miofibrilares obtidas de corvina (micropogonias furnieri).
(Universidade Federal do Pará, 2017-03-03) VIEIRA, Lorena Limão; LOURENÇO, Lúcia de Fátima Henriques; http://lattes.cnpq.br/7365554949786769
The interest in biodegradable films as food packaging is a worldwide trend that has increased significantly in recent years. The myofibrillar proteins, particularly fish ones, have been gaining interest in film technology. The films made from polysaccharides or proteins have excellent mechanical and optical properties, but these films have a high water vapor permeability (WVP). The incorporation of hydrophobic substances, such as stearic acid, into the film-forming solution, is an alternative to increase the barrier properties of the film to water vapor. But to facilitate the incorporation of the lipid in the protein matrix, it is necessary to add surfactant, which are substances capable of interacting with the protein and the fatty acid. The objective of this work was to develop and characterize films of myofibrillar proteins obtained from corvina waste (Micropogonias furnieri) using glycerol as plasticizer, sodium dodecyl sulfate (SDS) as surfactant and stearic acid (SA) as lipid, to improve the technological properties of the film. The characterization of the waste and lyophilized myofibrillar proteins (MP) was performed, indicating that the raw material had a high protein content (96.03% b.s.), important for the formation of the biopolymer matrix. A complete factorial planning was done to define the region of better mechanical, physical and barrier properties of films. The optimized biofilm was prepared with 2.84% MP, 3.18% SA, and 78.41% SDS and 30% glycerol. Concentrations of SA and SDS significantly reduced the WVP, reaching 5.87E-11 g m m-² s-¹ Pa-¹, representing a reduction of 31% when compared to the control biofilm. The mechanical properties of the optimized biofilm were favored, presenting 235.60% of elongation and 6.35 MPa of tensile strength producing stronger and more flexible films. The values of transparency were high, indicating tendency to opaque and yellowish tone, however, with excellent UV barrier properties and it can be used in light sensitive foods. The optimized film also presented good thermal stability and the microstructure revealed a structural change in the filmogenic matrix, in relation to the control, with presence of grooves and protuberances on the surface, confirmed by X-ray diffraction, which indicated the influence of SDS and SA on crystallinity of the film. A 22% increase in solubility and a slight decrease in the swelling of the optimized film were observed.
Acesso aberto (Open Access)
Obtenção, avaliação e aplicabilidade de filmes biodegradáveis de proteínas de pescada amarela (cinoscyon acoupa), amido de mandioca (manihot esculenta c.) e ácidos graxos em frutos pós- colheita
(Universidade Federal do Pará, 2020-12-07) LAGO, Gleice Vasconcelos Pereira do; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219; JOELE, Maria Regina Sarkis Peixoto; http://lattes.cnpq.br/2618640380469195
The general objective of this thesis is “Obtaining, evaluating and applicability of biodegradable films of yellow hake (Cinoscyon acoupa), cassava starch (Manihot esculenta C.) and fatty acids in post-harvest fruits” and presents three interconnected articles. The first one entitled “Influence of the addition of glycerol and fatty acids on the rheological and technological properties of films composed of Cynoscion acoupa”, and deals with the study carried out with films of lyophilized myofibrillar proteins (PML) and fatty acids (stearic (PE), palmitic (PP) and caproic (PC)). The addition of PE and PP acids and glycerol significantly increased the viscosity of film-forming solutions (SF). The films named PE (1% PML (w/v) and 0.5% stearic acid (w/w)) and PP (1% PML (w/v) and 0.5% palmitic acid (w/w)) showed better water vapor permeability (PVA) and solubility properties, with more ordered structures (crystalline) and better thermal resistance when compared to the other films. The second article “Rheological and technological properties of composite films obtained with myofibrillar proteins from yellow hake (Cynoscion acoupa) and cassava starch (Manihot esculenta C.)”, evaluated the influence of different concentrations of proteins and starch on the rheological properties of SF and film technologies. Starch had a significant influence on SF. The analyzes indicated that the interaction between these biopolymers is positive for the production of packaging for different types of food, and the composite film F4 (1% PML (w/v), 2% starch (w/v) and 30% glycerol (w/w)) showed better PVA, solubility, mechanics and thermal resistance. The third “Evaluation of the biodegradation of films composed of proteins from yellow hake(Cynoscion acoupa), palmitic acid and starch (Manihot esculenta C.) and its application as a coating on post-harvest fruits”, evaluated the biodegradation of the films in soil and the behavior of papaya fruits coated with F1 film (commercial film - PVC polyvinyl chloride), and coatings F2 (1% PML (w/v) and 0.5% palmitic acid (w/w)) and F3 (1% PML (w/v), 2% starch (w/v) and 30% glycerol (w/w)), using the uncoated fruit as a control. Biodegradation indicated that the F2 and F3 films were considered biodegradable and as expected the F1 did not degrade, however, the F2 was considered the most suitable to be applied as a coating when compared to the others, as it increased its shelf life by 6 days of the fruits. ..
Acesso aberto (Open Access)
Propriedades tecnológicas e antimicrobiana de biofilmes de proteínas de peixe com óleo essencial de cravo.
(Universidade Federal do Pará, 2017-09-18) SILVA, Wagner Barreto da; LIMA, Consuelo Lúcia Sousa de; http://lattes.cnpq.br/2971385954203459; LOURENÇO, Lúcia de Fátima Henriques; http://lattes.cnpq.br/7365554949786769
The objective of this work was to evaluate the antimicrobial capacity of biofilms elaborated with proteins extracted from filleting residues of gilt (Brachyplatysoma roussauxii) added with essential oil of clove (Eugenia caryophyllata), besides analyzing the technological properties of the films. Two biofilms were prepared, one with 2% of myofibrillar proteins extracted from fillets and the other with 2% of gelatin of the skin of gilt, by the casting method. The concentrations of clove essential oil were 0% (white), 1%, 1.5% and 2% relative to the volume of solution. In the films, the antimicrobial activity was evaluated by the disc-diffusion method and mechanical analyzes (elongation and tensile strength), barrier (permeability to water vapor, water solubility and swelling index), thickness, color and characteristics morphological and structural analyzes using scanning electron microscopy (SEM). Myofibrillar proteins and gelatins extracted from gilt shavings and skin are excellent raw materials for application in biofilms, with protein content of 94.92% and 79.67% and yield of 14.10% and 32.92%, respectively. The biofilms added clove essential oil presented excellent values of water vapor permeability and high elongation values contributing to a better application in food, as well as yellow coloration with low intensity. The biofilms of myofibrillar proteins had an inhibitory effect on the concentrations used against Gram positive bacteria, Staphylococus aureus and Enterococus fecalis. Gelatin biofilms added with OEC did not inhibit the growth of Gram-positive and Gram-negative bacteria.