Navegando por Assunto "Proteinas miofibrilares"

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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)
Aproveitamento sustentável dos resíduos de pescado para obtenção de revestimentos/filmes, aplicação na conservação pós-colheita de goiabas (psidium guajava l.), estudo da estabilidade e funcionalidade desses filmes
(Universidade Federal do Pará, 2021-03-01) PEREIRA, Glauce Vasconcelos da Silva; Calado, Verônica; LOURENÇO, Lúcia de Fátima Henriques; http://lattes.cnpq.br/7365554949786769
In the present study, a coating based on myofibrillar proteins (PML), corn starch (AM), and gum arabic (GA) were used to verify the rheological behavior and its influence on the extension of the shelf life of 'cortibel' guavas. Subsequently, the effect of the mixture PML/glycerol 10% (Gly) – coating A, and PML/Gly/GA at concentrations of 30 and 40% (w/w) of Gly, called coatings B and C, respectively, was evaluated. in the quality of 'paloma' guava. For technological characterization, the functional properties and moisture sorption behavior of PML and Gly-based films were evaluated at concentrations of 5, 10, 15, 30, and 40%. After selecting the best behavior of the PML-based films, the interactions between PML and GA were analyzed in the different proportions (10.0:0.0; 9.5:0.5; 9.0:1.0; 8 .5:1.5; 8.0:2.0 and 7.5:2.5), called E1, E2, E3, E4, E5 and E6, respectively. Among the analyzed coatings (PM; AM; GA), AM had the highest viscosity (p ≤ 0.05), followed by PML and GA, characterizing very viscous, viscous, and very diluted dispersions, respectively. The loss of mass and firmness of fruits coated with PML and AM showed lower (p ≤ 0.05) percentages on the evaluated days. Coating C (1%PML/40%Gly/1%GA) delayed the ripening rate (p ≤ 0.05) of the coated fruits. In the sorption process, films obtained curves of type II (5% glycerol) and III (10 to 40% glycerol), in which high concentrations of Gly resulted in an increase in their water content and a decrease in hysteresis until their disappearance. The E4 blend film (8.5%PML/1.5%GA/40%Gly) showed greater compatibility and integration into the structure, with low permeability to water vapor, a property required for food packaging. It is concluded that the application of coatings had a positive contribution by delaying the maturation process and increasing the commercial life of 'cortibel' and 'paloma' guavas. Fish PML films with low glycerol addition can be industrially processed and used to protect food, as they showed low hygroscopicity. The incorporation of GA in the mixed films (PML/Gli/GA) had an important effect on the technological properties, due to the interaction with myofibrillar proteins and glycerol.
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. ..