Scielo RSS <![CDATA[Latin American applied research]]> vol. 45 num. 2 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<b>Evaluation of dispersible protein content during convective drying of soybeans under different drying air temperatures</b>]]> The present study assesses the effects of different drying conditions on dispersible protein content of soybeans. Experiments were conducted in a pilot-scale convective dryer operated at different air temperatures (60, 80 and 100°C) at a fixed velocity (1.0 m/s). Moisture and dispersible protein content were measured as a function of time. It was observed that drying air temperature influenced the dispersible protein content of the dried soybeans: when soybeans were submitted to air at 60, 80 and 100°C for 18 min, the dispersible protein content decreased from 33.0 kg of dispersible protein /100 kg of dry solids (d.s.) to 29.0, 20.5 and 12.0 kg /100 kg d.s., respectively. The temperature of 60°C proved to be a satisfactory condition for preserving the dispersible proteins of soybeans. However, using air at 100°C for short periods of time (< 6 min) was also a good option for minimizing protein denaturation during drying <![CDATA[<b>Effect of pretreatments on sesame cake protein hydrolysis by alcalase</b>]]> In the present work, the effects of pretreatments on hydrolysis of sesame cake protein and enzyme stability were investigated. Heat, microwave and sonic pretreatments were applied to sesame cake protein as pretreatments before the enzymatic hydrolysis reaction. The sesame cake protein was hydrolyzed by Alcalase enzyme <![CDATA[<b>A novel enteric polysacharide based on cellulose for sodium diclofenac encapsultaion</b>]]> The polymers that respond to chemical changes, such as pH, are used in the modified drugs release. This paper presents the microencapsulation of diclofenac sodium, it has the disadvantage to produce gastric irritation, therefore it is suitable for encapsulation. As coating was used carboxymethylcellulose (CMC) grafted with benzyl chloride. The microencapsulation method used was spray drying. It was obtained encapsulation efficiency to 90 % and a 57 % yield. Particles were characterized by FTIR, X rays diffraction and SEM. In vitro dissolution test allowed to evaluate release of the active in simulated gastric and intestinal juice. The results showed excellent response in acid medium giving 2.7 %, result that confirmed the enteric behavior. The kinetic release showed that Peppas model was the best to match the experimental points. Diffusional exponent indicates that the drug transport had non-fickian behavior. The difference between Peppas and Schott models is discussed <![CDATA[<b>Lie group analysis of mhd natural convection heat and mass transfer flow of a casson fluid over an inclined surface with chemical reaction</b>]]> Natural convective heat and mass transfer of a non-Newtonian fluid over an inclined surface with uniform magnetic field and chemical reaction has been investigated numerically. The Casson fluid model is used to characterize the non-Newtonian fluid behavior and the first order of chemical reaction is considered. Lie group analysis is employed to obtain the symmetries of the governing system of partial differential equations and they reduce them to a system of ordinary differential equations via scaling transformation. Numerical computations have been carried out using the fourth order Runge-Kutta scheme with shooting techniques with a systematic guessing values of F1'(0), F3' and F4'(0). The procedure is repeated until we get the results up to the desired degree of accuracy, namely 10-5 . <![CDATA[<b>Extraction of <i>Mucuna aterrima</i> seed oil using compressed propane and quantification of l-dopa in the defatted meal</b>]]> The aim of this study was to extract the oil of Mucuna seeds using compressed propane as the solvent, in order to concentrate the L-Dopa content of the defatted Mucuna meal. The experiments were performed in a laboratory-scale unit with a constant propane flow rate of around 0.8 mL/min and temperature and pressure ranges of 30-60 °C and 80-120 bar, respectively. The results revealed that temperature is an important variable for the extraction yield obtained with propane. It was observed that the concentration of L-Dopa present in the defatted seed meal was greater than that in the seeds without the removal of oil. Quantitative analysis of the oil extracted under the different experimental conditions investigated showed no significant differences in terms of fatty acids (p>0.05), the major oil component being linoleic acid (omega-6), along with the presence of around 5% of linolenic acid (omega-3). The kinetics of the oil extraction with propane was also investigated for the operating conditions considered <![CDATA[<b>Rotation of a porous approximate sphere in an approximate spherical container</b>]]> The problem of steady rotation of a porous approximate sphere located at the center of an approximate spherical container has been investigated. The Brinkman's model for the flow inside the porous approximate sphere and the Stokes equation for the flow in an approximate spherical container were used to study the motion. The torque experienced by the porous approximate spherical particle in the presence of cavity is obtained and wall correction factor is calculated. The special cases of rotation of a porous sphere and a solid sphere in a spherical container are obtained from the present analysis <![CDATA[<b>Ascorbic acid degradation kinetic for microwave dried basil, purslane and celery leaves</b>]]> In this study, the goal was to evaluate the ascorbic acid degradation in basil, purslane and celery leaves during microwave drying. The effects of microwave output power and sample amount on ascorbic acid loss in basil, purslane and celery leaves were investigated. The method for the determination of ascorbic acid content was based on the reaction between ascorbic acid and 2,6-dichloroindophenol and was successfully applied to basil, purslane and celery leaves. Increasing microwave output power and decreasing sample amount led to higher degradation rates in basil, purslane and celery leaves. Ascorbic acid degradation kinetics in basil, purslane and celery leaves during microwave drying followed a first-order reaction. The activation energy values were also calculated using an exponential expression based on Arrhenius equation for degradation of ascorbic acid <![CDATA[<b>Multi-objective reconfiguration of a distribution system including probabilistic loads and distributed generations</b>]]> The present study suggests a method to reconfigure a 13-bus distribution system which includes probabilistic loads (PLs) and Distributed Generations (DGs). Reconfiguration is a specific process to determine the best configuration of networks. It is usually assumed that loads are constant, while we know that they have probabilistic nature and change regularly, the above mentioned facts were taken into account in the current study. Considering that 3 DGs (wind farms) have been added to the distribution system, the generation is also probabilistic depending on weather change. The "Sifting Algorithm" has been used for reconfiguration because it has a high accuracy and significant speed. The proposed method is simulated on a well-known distribution network. The achieved results were highly satisfactory and applicable <![CDATA[<b>Effect of oil extraction with supercritical CO<sub>2</sub> and organic solvents on antioxidant capacity and total phenolic content of <i>Mucuna </i>meal</b>]]> The antioxidant capacity and total phenolic content of defatted and raw meals of three different varieties of Mucuna seeds (aterrima, cinerium and deeringiana) were investigated. Oil extraction was performed with supercritical CO2, dichloromethane and hexane. Supercritical fluid extraction was carried out at 313 K and 333 K in the pressure range from 15 MPa to 25 MPa. The DPPH (2,2-diphenyl-1-picryl-hydrazyl) assay always revealed a positive influence of oil removal on the antioxidant activity of the meals (i.e.; a negative influence on EC50) for all the considered varieties of Mucuna. The highest content of total phenols in the defatted material was approximately 18-26 % higher than those found in the raw meals (≈4.3-5.5 g GAE/100 g) when examining samples of the same Mucuna variety. A non negligible role of the oil extraction method in the total phenolic content of defatted Mucuna was evidenced in 2/3 of the examined varieties. The oil extraction yields were determined at all the investigated conditions, but the best results were obtained when using the organic solvents (≈5.2-7.4 %) <![CDATA[<b>Theoretical analysis of overlaid cement concrete pavement with crack</b>]]> In this paper, overlaid Portland cement concrete (PCC) with crack subjected to vehicle load is considered based on theoretical analysis. In order to build efficient model, PCC is reduced to an elastic plate on Winkler foundation. Fourier integral transform, residue theorem and Lobatto-Chebyshev integration formula are used to obtain the analytical solutions on the stress and strain fields of the pavement and stress intensity factors of the crack tip. Stress intensity factors are numerically calculated. The stress intensity factors of the crack tips(b) in the pavement with 10cm thickness overlay are reduced heavily, especially for I type crack. Overlay thickness is very significant factor that effect the value of stress intensity factor of I type crack, rather than II type crack. However, stress intensity factors are less affected by elastic modulus of overlay material