Edwin E. Garcia Rojas
Federal Fluminense University
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Featured researches published by Edwin E. Garcia Rojas.
Critical Reviews in Food Science and Nutrition | 2016
Fabíola Cristina de Oliveira; Jane Sélia dos Reis Coimbra; Eduardo Basílio de Oliveira; Abraham Damian Giraldo Zuniga; Edwin E. Garcia Rojas
The products formed by glycosylation of food proteins with carbohydrates via the Maillard reaction, also known as conjugates, are agents capable of changing and improving techno-functional characteristics of proteins. The Maillard reaction uses the covalent bond between a group of a reducing carbohydrates and an amino group of a protein. This reaction does not require additional chemicals as it occurs naturally under controlled conditions of temperature, time, pH, and moisture. Moreover, there is growing interest in modifying proteins for industrial food applications. This review analyses the current state of art of the Maillard reaction on food protein functionalities. It also discusses the influence of the Maillard reaction on the conditions and formulation of reagents that improve desirable techno-functional characteristics of food protein.
Journal of Chromatography B | 2009
Rita de Cássia Superbi de Sousa; Jane Sélia dos Reis Coimbra; Luis Henrique Mendes da Silva; Maria do Carmo Hespanhol da Silva; Edwin E. Garcia Rojas; Antonio António Augusto Vicente
The objective of this study was to determine the thermodynamic parameters (Delta(tr)G, Delta(tr)H and Delta(tr)S) associated with lysozyme and conalbumin partitioning in aqueous two-phases systems (ATPS). Influence of salt type and polyethylene glycol (PEG) concentrations on the partition coefficient of lysozyme and conalbumin from egg white was studied. The evaluated ATPS were composed of PEG 1500 and inorganic salts (sodium citrate and sodium sulfate) at a temperature of 25 degrees C and pH 7.0, with PEG 1500 g mol(-1) concentrations of 14%, 16% and 18% (mass basis). Partitioning of lysozyme in PEG-citrate ATPS was enthalpically driven, however the PEG-sulfate ATPS was entropically driven. The tested systems can be employed for the separation of these two proteins in egg white, due to the fact that lysozyme migrates toward the polymeric phase and conalbumin to the saline phase in both ATPS. A high recovery of conalbumin in the saline phase of the PEG-sulfate ATPS was determined to be enthalpically driven.
International Journal of Food Properties | 2013
Edwin E. Garcia Rojas; Jane Sélia dos Reis Coimbra; Javier Telis-Romero
Vegetable oils are used in the industry of processed food, including deep-fat frying. This work determined data on the thermophysical properties of cotton, canola, sunflower, corn, and soybean oils. Thermal conductivity, heat capacity, density, and viscosity were measured within the temperature range of 299.15–433.15 K. The data showed that the temperature influenced the thermophysical properties of the oils studied. The developed correlations could be used to predict these properties within the range of temperatures studied.
Ciencia E Agrotecnologia | 2012
Clitor J.F. Souza; Edwin E. Garcia Rojas
This work characterizes the emulsifying properties of systems containing egg yolk (0.1; 1.0 and 2.5 % w/v) and polysaccharides (xanthan gum, carrageen, pectin and carboxymethylcellulose) and three different vegetable oils (sunflower, canola, and palm oils). Emulsifying activity and emulsion stability were measured of each combination and it was found the effect of the oil on emulsion stability correlated to the amount of monounsaturated fatty acid. Additionally, increased egg yolk concentration increased emulsifying activity by reducing coalescence of oil droplets. Lastly, 2.5% egg yolk and 0.2% polysaccharide generated emulsions with high emulsifying activity, excellent stability, and droplet size of 4.32 µm.
Materials Science Forum | 2015
Fernanda A. Sampaio da Silva; Edwin E. Garcia Rojas; Marcos Flavio de Campos
Nanotechnology has been shown as an important tool for developing intelligent devices. In particular, magnetic nanoparticles have been studied due their applications in cancer treatments. However, nanoparticles need to be tightly controlled in relation to size, shape and coating. It makes particles suitable for in vivo applications. In this work, magnetite nanoparticles were used for particle size characterization. Fe3O4 crystals were coated by polyethyleneglycol (PEG 4000). Three different techniques were performed to obtain the nanoparticles average diameter: Rietveld Analysis, Scherrer Equation and Nanosight®. Results indicate good properties.
Materials Science Forum | 2014
Fernanda A. Sampaio da Silva; Edwin E. Garcia Rojas; Sergio Antonio Romero; Marcos Flavio de Campos
Nowadays, superparamagnetic iron oxide nanoparticles are an important tool for cancer treatment, such as magnetic hyperthermia. The goal is heating diseased tissue and then tumor cells are destroyed. Magnetic nanoparticles are promising mainly because they have specific ability to reduce side effects. However, for in vivo applications, nanoparticles need to be coated by a biocompatible material. In this work, nanoparticles are coated by PEG (biocompatible polymer). Samples were produced by coprecipitation process. Information about particle size, magnetic properties and crystallinity were obtained.
Materials Science Forum | 2016
Fernanda A. Sampaio da Silva; Edwin E. Garcia Rojas; Marcos Flavio de Campos
The nanoparticle materials have been intensively studied in recent decades aiming mainly at the medical fields. In particular, nanoparticles of magnetite, Fe3O4, because it has physical and magnetic properties compatible with in vivo applications. However, even if the magnetite has low toxicity, it is necessary that the particles are coated with biocompatible material. In this work, Fe3O4 nanoparticles coated by a polymer blend of polyethylene glycol / polyvinylpyrrolidone (type core / layer) were analyzed. It was performed to study the thermal degradation of the polymer coating layer aimed at understanding the nature of the forces involved in adsorption surface of the metallic core.
Materials Science Forum | 2016
Fernanda A. Sampaio da Silva; Marcos Flavio de Campos; Edwin E. Garcia Rojas
Magnetic nanoparticles are devices able to optimize cancer treatments. In particular, magnetite nanoparticles are very effective in producing heat to cause lysis of tumor cells. However, in order that nanoparticles are internalized without causing damage to body they must be coated by biocompatible material. In this work, Fe3O4 nanoparticles were coated by a polymer blend: polyethylene glycol / polyvinylpyrrolidone. Some variations in mass ratio of polymer mixture were made. The effect of varying mass ratio in polymers was investigated. Samples were characterized by X-ray diffraction and Rietveld analysis. Moreover, hysteresis curves were analyzed. The results indicate good agreement between mass proportions used and physical and magnetic properties of nanocomposite.
Materials Science Forum | 2014
Fernanda A. Sampaio da Silva; Edwin E. Garcia Rojas; Girley F. Rodrigues; Bruno F.A. da Silva; Marcos Flavio de Campos
Malignant tumors are caused by uncontrolled multiplication of cells in the body. It is possible to stop the growth of atypical cells by overheating (hyperthermia). By the magnetization process of magnetite nanoparticles, energy is dissipated as heat (Joule effect), producing increase of temperature. This causes the rupture of cancer cells. In this work, magnetic nanoparticles were synthesized by coprecipitation method and coated by biocompatible material (chitosan or castor oil). The samples showed required characteristics of nanocrystallinity, superparamagnetism and biocompatibility. This was deduced from hysteresis curve, thermal analysis and X-ray Diffraction data. Thus, the nanocomposite exhibits excellent features for use in vivo.
Journal of Food Engineering | 2006
Jane Sélia dos Reis Coimbra; Ana Lúcia Gabas; Luis Antonio Minim; Edwin E. Garcia Rojas; Vânia Regina Nicoletti Telis; Javier Telis-Romero