Navegando por Autor "SILVA, Marcilene Paiva da"

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Acesso aberto (Open Access)
Extração supercrítica da polpa liofilizada de açaí (Euterpe oleracea Mart.): determinação de compostos bioativos e solubilidade
(Universidade Federal do Pará, 2021-04-26) SILVA, Marcilene Paiva da; ARAÚJO, Marilena Emmi; http://lattes.cnpq.br/8983914018546682; CARVALHO JÚNIOR, Raul Nunes de; http://lattes.cnpq.br/5544305606838748; https://orcid.org/0000-0002-4433-6580
The present study brings results related to the use of supercritical CO2 to obtain oil from the freeze-dried açaí pulp. During the period of this work, analyzes of bioactive compounds and prediction of oil solubility in supercritical CO2 were carried out in three municipalities in the state of Pará, Brazil: Anajás, Chaves and Saracá, and extractions were carried out under these conditions: 50 °C/350 bar, 60 °C/420 and 70 °C/490 bar. In this study, the levels of bioactive compounds present in the pulp before and after extraction were determined and the highest yields of oil in mass (57.06%) were obtained for the locality of Chaves. Based on the fatty acid composition, the levels of triglycerides present in the oil were predicted and the main predicted TAGs were OOO, POO, OLiO, PLiO and POP and the solubility prediction showed the same behavior of the global yields that increased as the pressure and temperature increased. Furthermore, after the extractions, there was an increase in the concentrations of bioactive compounds and in the antioxidant capacity in the lyophilized açaí pulp from all municipalities. The lyophilized pulp of the fruits of the açaí palm (Euterpe oleracea Mart.) from the three municipalities was also submitted to an evaluation of its morphological structure by the methods of Scanning Electron Microscopy (SEM) and X-ray Energy Dispersive Spectroscopy (EDS), which showed irregular shape and size of the pulp particles and presence of the chemical elements oxygen, potassium and calcium. Regarding the color parameters of the lyophilized pulp, the a* coordinate showed positive values, indicating that the samples tend to purple, the hue angle °Hue showed a certain tendency to the color range between red and purple. The results of the mineral profile showed that the minerals Ca and Mg from the pulp of the three regions studied were the minerals found in abundance, with concentrations ranging from 4951.55 μg/g to 5540.41 μg/g.
Acesso aberto (Open Access)
Simulação do fracionamento em coluna em contracorrente de óleo de peixe e de solução aquosa com dióxido de carbono supercrítico
(Universidade Federal do Pará, 2015-08-11) SILVA, Marcilene Paiva da; ARAÚJO, Marilena Emmi; http://lattes.cnpq.br/8983914018546682
This work had as its general objective the simulation with Aspen Hysys fractionation process using supercritical carbon dioxide in countercurrent multistage columns of an aqueous solution of ethanol and fish oil, employing cubic equations of state with binary interaction parameters extracted from a database previously prepared with different mixing rules for the equations of state of Soave-Redlich-Kwong (SRK), Peng-Robinson (PR), their respective modified and Redlich-Kwong Aspen (RK-Aspen), from experimental data of binary systems of methyl and ethyl esters, esters of fatty acids from fish oil, biocompounds, aqueous systems and minority components of vegetable oils. Overall, no significant differences in the prediction of phase balance for all equations of state used with the mixing rules of Quadratic, Mathias-Klotz-Prausnitz (MKP) with 2 and 3 parameters, KM1 with 3 parameters and RKAspen with 2 and 4 parameters. It is worth mentioning that the mixing rule RK-Aspen with 4 binary interaction parameters, presented the smallest absolute errors for most systems. The simulator used the equation of state of Soave-Redlich-Kwong as a thermodynamic package with the mixing rules of RK-Aspen. The simulations to 140 and 145 bar pressure and 60° C for the P1 and P8 showed that increased concentration (eC20:53) and ( eC22:63) occurred at the expense of the solvent consumption (carbon dioxide), i.e. with the increase of the ratio S/F, reaching 85.67% for S/F = 200 for P1 and 70.61% for S/F = 150 to the composition P8. The simulation results of this study at 145 bar and 60° C, with relations S/F of 70, 90, 110 and 130, using different fish oil compositions, exhibited higher yield of raffinate stream compared to simulated column literature, in the Aspen Plus using Peng-Robinson equation for all the relations S / F. As the quality of recovery of the compounds of interest (eC20:53 e eC22:63), both simulations showed similar performance. For the fractionation process of aqueous solutions were performed at 101 bar pressure and temperature of 333 K. The results showed that the simulations reproduced the experiments on most operating conditions in laboratory scale, pilot and industrial published in the literature.