Pequi pulp (Caryocar brasiliense Cambess): Drying kinetics and thermodynamic properties

  • RM Silva
  • GR Placido
  • DEC Oliveira
  • MAP Silva
  • M Caliari

Abstract

The objective of this study was to evaluate the drying kinetics of Pequi pulp (Caryocar brasiliense Cambess) at temperatures of 40, 50 and 60°C, and the thermodynamic properties for this process. Eleven mathematical models commonly used to represent the drying process of agricultural products were fitted to experimental data. The Fick's second law was used to determine the diffusion coefficients of Pequi fruits through the drying kinetics. The model of Midilli best represented the drying process of Pequi pulp. The calculated effective diffusivity was 4.69988 × 10-14, 5.277436 × 10-14 and 5.609491 × 10-14 (m2s-1) for temperatures of 40, 50 and 60°C, respectively, and the energy activation for the process was 7694.94 J mol-1. The enthalpy decreased with increasing temperature, with values of 5091.41, 5008.27 and 4925.13 (Jmol-1) for temperatures of 40, 50 and 60°C, respectively. The entropy values found were -251.01, -250.38 and -250.05 (J.Mol-1K-1) for the same temperatures. The values obtained from the Gibbs free energy for the drying of Pequi pulp increased with increasing temperature. The obtained data were consistent to the drying process, and the mathematical equations were effective to explain the migration of water within the product.

Keywords: Effective diffusivity, drying models, enthalpy, entropy, Gibbs free energy.

African Journal of Biotechnology, Vol 13(31) 3443-3449

Author Biographies

RM Silva
Federal Institute of Gioano - Rio Verde Campus, CP 66, 75901-970, Rio Verde, Gioas, Brazil
GR Placido
Faculty of the Graduate Program in Animal Science, Federal Institute Goiano, Rio Verde Campus, CP 66, 75901-970, Rio Verde, Goias, Brazil
DEC Oliveira
Faculty of the Graduate Program in Animal Science, Federal Institute Goiano, Rio Verde Campus, CP 66, 75901-970, Rio Verde, Goias, Brazil
MAP Silva
Faculty of the Graduate Program in Animal Science, Federal Institute Goiano, Rio Verde Campus, CP 66, 75901-970, Rio Verde, Goias, Brazil
M Caliari
Food Science and Trechnology, Federal University of Goias, CP 131, 74690-900, Goiania, GO, Brazil
Published
2015-09-13
Section
Articles

Journal Identifiers


eISSN: 1684-5315