José Antônio da Silva

The importance of heat against antinutritional factors from Chenopodium quinoa seeds

Chenopodium quinoa seeds have high protein content. The nutritional value of quinoa is superior compared with traditional cereals. Its essential amino acid composition is considered next to the ideal, and its quality matchesxa0that ofxa0milk proteins. In this study, the seed storage proteins from Chenopodium quinoa were extracted, fractionated, partially purified, and characterized. The structural characterization was performed by Tricine-SDS-PAGE and two-dimensional electrophoresis, and it confirmed the presence of proteins of molecular weight of 30 and 7kDa, probably corresponding to lectins and trypsin inhibitors, respectively. The functional characterization of these proteins evidenced their activity as antinutritional factors due to their in vitro digestibility. Quinoa proteins have an excellent amino acid composition with many essential amino acids. In vitro digestibility evaluation indicated that heat-treated samples showed a more complete digestion than the native state samples. Quinoa seeds can be an important cereal in human diet after adequate heat treatment.

Purification, partial characterization and antimicrobial activity of Lectin from Chenopodium Quinoa seeds

A novel lectin was isolated from the seeds of Chenopodium quinoa. To achieve this end, the crude extract from the quinoa was submitted to two purification steps, Sephadex G50 and Mono Q. The hemagglutinating activity showed that this lectin agglutinates human erythrocytes. Its activity is inhibited by glucose and mannose, and remained stable under a wide range of pH levels and temperatures. The quinoa lectin was found to be a heterodimeric lectin of approximately 60 kDa, consisting of two subunits of approximately 25 kDa and 35 kDa. This lectin had its antimicrobial activity tested against several bacteria strains and effectively inhibited three strains. These strains were all Gram-negative, making this lectin a promising antimicrobial tool.

Extraction, purification and characterization of inhibitor of trypsin from Chenopodium quinoa seeds

A novel trypsin inhibitor of protease (CqTI) was purified from Chenopodium quinoa seeds. The optimal extracting solvent was 0.1M NaCl pH 6.8 (p < 0.05). The extraction time of 5h and 90 °C was optimum for the recovery of the trypsin inhibitor from C. quinoa seeds. The purification occurred in gel-filtration and reverse phase chromatography. CqTI presented active against commercial bovine trypsin and chymotrypsin and had a specific activity of 5,033.00 (TIU/mg), which was purified to 333.5-fold. The extent of purification was determined by SDS-PAGE. CqTI had an apparent molecular weight of approximately 12KDa and two bands in reduced conditions as determined by Tricine-SDS-PAGE. MALDI-TOF showed two peaks in 4,246.5 and 7,908.18m/z. CqTI presented high levels of essential amino acids. N-terminal amino acid sequence of this protein did not show similarity to any known protease inhibitor. Its activity was stable over a pH range (2-12), temperatures range (20-100 °C) and reducing agents.

Production and characterization of lectin from Bauhinia holophylla (Fabaceae:Cercideae) calli

Bauhinia holophylla is a woody plant found in the Brazilian Cerrado used in folk medicine to treat diabetes. Lectins are glycoproteins with several biotechnological applications and play important roles in plant defenses and in medicine. Lectins have been produced in vitro using plant tissue culture techniques. This study shows the production and characterization of lectin from B. holophylla by callus culture. Calli were obtained from leaf segments placed on woody plant and Murashige and Skoog media supplemented with 2,4-dichlorophenoxyacetic acid (0, 4.52, 9.05, 18.10xa0µM) or 6-benzylaminopurine (0, 4.44, 8.88, 17.75xa0µM), in the presence or absence of light. The highest concentrations of lectin expressed by hemagglutination activity were observed in green and compact callus induced in woody plant medium supplemented with 6-benzylaminopurine in the presence of light, which showed specificity by all types of erythrocytes tested. The highest concentrations of lectin (128xa0HUxa0mg−1) and fresh weight of callus were observed in the stationary phase (41st–60thxa0day). Lectin was not detected in subcultured calli. d-Galactose promoted the highest inhibitory effect on the lectin activity in human erythrocytes ABO system, especially B-type. Lectin has been shown to be a stable protein, maintaining its hemagglutination activity after incubation at a wide range of temperatures, pH values and ethylenediaminetetraacetic acid concentrations.

Analysis of combustion efficiency in a pelletizing furnace

The objective of this research is to assess how much the improvement in the combustion reaction efficiency can reduce fuel consumption, maintaining the same thermal energy rate provided by the reaction in a pelletizing furnace. The furnace for pelletizing iron ore is a complex thermal machine, in terms of energy balance. It contains recirculation fan gases and constant variations in the process, and the variation of a single process variable can influence numerous changes in operating conditions. This study demonstrated how the main variables related to combustion in the burning zone influence fuel consumption (natural gas) from the furnace of the Usina de Pelotizacao de Fabrica (owned by VALE S/A), without changing process conditions that affect production quality. Variables were analyzed regarding the velocity and pressure of the fuel in the burners, the temperature of the combustion air and reactant gases, the conversion rate and the stoichiometric air/fuel ratio of the reaction. For the analysis, actual data of the furnace in operation was used, and for the simulation of chemical reactions, the software Gaseq® was used. The study showed that the adjustment of combustion reaction stoichiometry provides a reduction of 9.25% in fuel consumption, representing a savings of US

Application of optimization for improvement of the efficiency of louvered-fin compact heat exchangers

2.6 million per year for the company.

Fatores antinutricionais e digestibilidade “in vitro” de folhas de Pereskia aculeata Miller

A few decades ago, the product development process was just based on a trial and error procedure, and the designers experience. The need for a new way to design and manufacture more economical and sustainable products corroborates increasingly to a new vision of how to create new products for the benefit of society. Modern numerical tools allow greater knowledge about the physical phenomena involved in engineering problems and enable cost reduction with trials and time of manufacture and projection. Among the equipment that can be mentioned where numerical simulation is used, can be found heat exchangers, which are capable of accomplishing the heat transfer between two fluid medias with different temperatures. Within the range of existing exchangers, this work will address a compact model with louvered fins, widely used in the automotive and aerospace industries, mainly due to their high thermal exchange surface vs occupied volume ratio. The heat exchanger surface is analised using computational fluid dynamics tecniques disposable in the commercial code ANSYS CFX14® to reproduce the flow at service condition. Genetic optimization routines are used to increase the performance of heat exchanger. As a result, a heat transfer surface is obtained with about a 25% better performance according to the selected objective function. The dimensionless factor of the convective heat transfer coefficient (Colburn factor, j) and the friction factor (Fanning factor, f) used in (Wang et al.,1998), are employed for simulation. Experimental data are also used for validation.