Campinas, Brazil
Campinas, Brazil
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Silva S.M.,EXTRAE | Silva S.M.,Ghent University | Sampaio K.A.,Ghent University | Ceriani R.,University of Campinas | And 4 more authors.
Journal of Food Engineering | Year: 2013

In this work, the adsorption of carotenes and phosphorus from crude palm oil onto acid activated bleaching earth was investigated under bleaching conditions, i.e. high temperature (90, 105 and 115 C) and low pressure (less than 50 mbar). Bleaching earth was added to palm oil in a range of 0.5-3.0 wt%. Results presented in this work suggest that adsorption of β-carotene increases with temperature, while phosphorus adsorption was less affected. Both the pseudo-first-order and the pseudo-second-order kinetic model describe efficiently the β-carotene experimental data. Intra-particle diffusion is involved in β-carotene adsorption mechanism, although it is not the sole rate limiting step in the adsorption onto acid activated bleaching earth. Phosphorus adsorption was too fast resulting in a lack of kinetic data. The equilibrium data were described better by Langmuir and Freundlich models, for β-carotene and phosphorus, respectively. A multi-component Freundlich type isotherm was tested. Its competition coefficients were too low, and it assumed the same form as the monocomponent Freundlich. A thermodynamic study demonstrated that β-carotene and phosphorus adsorption is spontaneous, endothermic and an entropy-driven process. Isosteric heat values suggest that the interactions between adsorbate and adsorbent are heterogeneous. © 2013 Elsevier Ltd. All rights reserved.

Silva S.M.,EXTRAE | Rocco S.A.,University of Campinas | Sampaio K.A.,EXTRAE | Taham T.,EXTRAE | And 3 more authors.
Food Chemistry | Year: 2011

A normal-phase HPLC method for analysis of carotenes, tocopherols and tocotrienols has been developed and validated. In this work we presented a modification to the official AOCS method for analysis of tocols which allowed simultaneous quantification of the three groups of compounds, including carotenes. Analytes were separated using a gradient mobile phase (hexane and isopropanol) and with a gradient flow rate (1-2 mL min -1). The column effluent was monitored by Photo Diode Array detector (PDA) set at 292 nm (tocols) and 455 nm (β-carotene) and by fluorescence detector set at an excitation wavelength of 290 and 330 nm emission. Inter- and intra-run accuracies and precision of the analytical method were better than ±15%. The lower limit of quantification was 5.0 mg L -1 for the tocols and 0.1 mg L -1 for carotenes. The method has been applied for the quantification of these compounds in Amazon oils. © 2011 Elsevier Ltd. All rights reserved.

Matricarde Falleiro R.M.,LPT | Meirelles A.J.A.,EXTRAE | Krahenbuhl M.A.,LPT
Journal of Chemical Thermodynamics | Year: 2010

(Vapor + liquid) equilibrium (VLE) data for three binary mixtures of saturated fatty acids were obtained by differential scanning calorimetry (DSC). However, changes in the calorimeter pressure cell and the use of hermetic pans with holes (φ{symbol} = 250 mm) in the lids were necessary to make it possible to apply this analytical technique, obtaining accurate results with smaller samples and shorter operational times. The systems evaluated in this study were: myristic acid (C14:0) + palmitic acid (C16:0), myristic acid (C14:0) + stearic acid (C18:0), and palmitic acid (C16:0) + stearic acid (C18:0), all measured at 50 mm Hg and with mole fractions between 0.0 and 1.0 in relation to the most volatile component of each diagram. The fugacity coefficients for the components in the vapor phase were calculated using the Hayden and O'Connell method [J.G. Hayden, J.P. O'Connell, Ind. Eng. Chem. Process Design Develop. 14 (3) (1975) 209-216] and the activity coefficients for the liquid phase were correlated with the traditional gE models (NRTL [H. Renon, J.M. Prausnitz, Aiche J. 14 (1968) 135-144], UNIQUAC [D.S. Abrams, J.M. Prausnitz, Aiche J. 21 (1975) 116-128], and Wilson [J.M. Prausnitz, N.L. Linchtenthaler, E.G. Azevedo, Molecular Thermodynamics of Fluid-phase Equilibria, River-Prentice Hall, Upper Saddle, 1999]). The sets of parameters were then compared in order to determine which adjustments best represented the VLE. © 2009 Elsevier Ltd. All rights reserved.

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