Authors:W. Cortez-Vega, G. Fonseca, B. Zanette and C. Prentice
The appropriate number of washing cycles for obtaining most of the surimi-like materials is not well defined in literature. The aim of this work was to investigate the influence of the number of washing cycles (one, two, or four) on the quality of surimi-like material obtained from mechanically deboned chicken meat (MDCM) using the bleaching method with sodium bicarbonate. The product was evaluated based on its chemical and physical characteristics. The chemical compositions of samples showed an increase in protein (45.7 to 89.9%, dry basis) and decrease in fat (49.1 to 7.0%, dry basis) contents, while the moisture content increased from 69.5 to 79.1% after four washing cycles. Washing diminished yield. Gel prepared with MDCM washed once showed the lowest gel strength (507.1 g.cm). It thereafter increased to 546.0 and 602.7 g.cm after double and quadruple washings, respectively. Higher content of myofibrillar proteins and higher whiteness were also obtained after successive washings. It was concluded that four washing cycles was the most appropriate method for producing surimi-like material from MDCM.
Authors:V.M. Nascimento, K.M. Nascimento and G.G. Fonseca
Microalgae are promising alternatives to sequestration of carbon and reduction of environmental problems, e.g. the greenhouse effect and industrial water pollution. Depending on the growth conditions, microalgae can differ in their metabolism products, leading them to grow at different rates. Intracellular reactions and nutritional requirements from cell metabolism, as well as biomass composition, may vary in function of the temperature. In this study, the biotechnological potential of three microalgae strains from the species was evaluated in terms of growth, biomass composition, fatty acid profile, and chlorophyll and carotenoids contents. Each of the three species demonstrated different potential depending on their metabolisms: Scenedesmus spinosus presented fastest growth and had the highest protein content (52.99%), Pseudokirchneriella subcapitata presented the highest content of lipid extracted (26.51%), and Scenedesmus acuminatus showed increased production of chlorophyll (5.25 mg l–1) and carotenoid (1.02 mg l–1) pigments.
Authors:A. S. Fonseca, J. N. G. Frydman, R. Santos and M. Bernardo-Filho
Acetaminophen (AAP), acetylsalicylic acid (ASA) and dipyrone (DIP) are antipyretic and analgesics drugs that have wide use in health sciences. Some drugs can modify the labeling of blood elements with technetium-99m (99mTc). This work has evaluated the effect of AAP, ASA and DIP on the labeling of the blood elements with 99mTc. Blood was incubated with different concentrations of the drugs before the 99mTc-labeled process. Plasma (P), blood cells (BC), insoluble (IF-P, IF-BC) and soluble (SF-P, SF-BC) fractions were separated and percentage of radioactivity (%ATI) in each fraction was determined. Data have shown that the antipyretic drugs used in this study did not significantly modify the fixation of 99mTc on the blood elements when the experiments were carried out with the doses usually used in human beings. Although the experiments were carried out with rats, it is possible to suggest that AAP, ASA or DIP should not interfere with the procedures in nuclear medicine involving the labeling of blood elements with 99mTc
Authors:A. J. D. Fernandes, J. H. P. Barbosa, O. G. Silva, M. G. Fonseca, L. H. N. Arakaki and J. G. P. Espínola
Silica/monetite nanocomposites were synthesized through controlled hydrolysis of tetraethoxysilane at concentrations of 5, 10, 15, and 20% mol/mol of calcium phosphate forming the solids named CaPSil1, CaPSil2, CaPSil3, and CaPSil4, respectively. XRD patterns showed formation of nanocomposites with a decrease in crystallinity. The NMR 29Si spectra suggested an increase in the content of incorporated silica with reduction of Q3 (–SiOH) signal, which contributes for mass loss, in agreement with thermogravimetry. The incorporation of silica increased the chemical stability of the precursor phosphate in an acidic medium.
Authors:Luiza N. H. Arakaki, V. H. A. Pinto, V. L. S. Augusto Filha, M. G. Fonseca, J. G. P. Espínola, Tomaz Arakaki and Claudio Airoldi
A new material containing a potential ligand for transition metals was prepared through the reaction of 3-aminopropyltrimethoxysilane and thioglycolic acid. The new adsorbent was characterized by elemental analyses, infrared spectroscopy, solid-state 13C nuclear magnetic resonance, thermogravimetric analysis, transmission electron microscopy, and specific surface area calculations. The formulated material was used in the removal of cobalt, copper, and nickel cations from aqueous solutions. Calorimetric titration was applied to study the interaction of these cations with the new adsorbent; the latter displayed a chelating moiety with basic centers containing nitrogen, oxygen, and several sulfur atoms, capable of capturing cations from aqueous solutions. This process of extraction was carried out by a batch method to yield the following order of maximum retention capacity: Ni > Co > Cu. The process of cation interactions showed exothermic enthalpies. The calculated ΔG values are in agreement with the spontaneity of the proposed reactions and conformed to the values found by applying the Langmuir model to these systems. The positive entropy and negative enthalpy values indicated that the reactions are favorable.
Authors:José Geraldo de P. Espínola, Evandro P. S. Martins, Franklin P. Aguiar, Haryane R. M. Silva, M. G. Fonseca, L. N. H. Arakaki and Ercules E. S. Teotônio
The complex BiCl3·L (L = 1,10-phenanthroline) was synthesized and characterized by elemental analysis and infrared spectroscopy (IR). Infrared spectroscopy data suggested that the nitrogen atom of the aromatic ring is bonded to the bismuth atom. The kinetic study of thermal degradation was determined by non-isothermal thermogravimetry. Two methods based on integral equation of Coats-Redfern, were necessary for determining the kinetic trip: the fitting method, known as the checking model and an iso-conversional method. The latter gives the activation energy for each degree of conversion and the first, the kinetic model gives activation energy and the pre-exponential factor for thermal decomposition processes that occur through a single simple mechanism. The kinetic parameters, Ea and log A for the heating rates of 5, 10, and 15 min K−1, were determined considering the decomposition model denoted by F0/R1 in the range of degree of conversion between 0.065 and 0.71.
Authors:J. D. T. Arruda-Neto, A. C. Cestari, C. B. Zamboni, M. Saiki, G. P. Nogueira, L. E. C. Fonseca, M. V. Manso-Guevara, A. Deppman, V. P. Likhachev, J. Mesa, O. A. M. Helene, S. A. C. Jorge, M. N. Martins, A. N. Gouveia, O. Rodriguez, F. Guzmán and F. Garcia
Neutron activation analysis has been used to study uranium incorporation in poultry bones as function of chow doped with: (a) uranium (20 ppm); (b) U-doped food (20 ppm) plus phytase (120 ppm) and (c) U-doped food (20 ppm) plus phytase (180 ppm). To investigate this situation experiments involving several groups of Cobb broilers was performed. Two animals per group were sacrificed weekly up to their adultness and uranium concentration in the tibia was measured. It was observed that the concentration of uranium (µg U/g bone) is decreasing all along the animal life spanning period of 14-42 days. This behavior suggests that the skeleton mass is growing faster than the corresponding accumulation of uranium. The administration of phytase seems not to alter this scenario.