Kinetic and thermodynamic compensation study of the hydration of faba beans (Vicia faba L.)

Autor(es)

Garvin, A. ^[1] ; Augusto, P. E. D. ^[2] ; Ibarz, R. ^[1] ; Ibarz, A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Lleida, Food Engn Unit, Food Technol Dept, Ave Alcalde Rovira Roure, 191, Lleida 25198, Catalonia - Spain

^[2] Univ Sao Paulo, Dept Agrifood Ind Food & Nutr LAN, Luiz Queiroz Coll Agr ESALQ, Piracicaba, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Food Research International; v. 119, p. 390-397, MAY 2019.
• Citações Web of Science: 0

Resumo

This work applies kinetic and thermodynamic compensation to evaluate the kinetics of hydration of faba beans. A mechanism was proposed, consisting of a zero-order adsorption step followed by a first-order desorption step, with both reactions going through a transition state with a previous equilibrium stage. The kinetic constants were obtained from a previous study for pHs 3, 6, 9 and 12 and at temperatures of 20, 35, 50 and 65 degrees C. From these kinetic constants, the equilibrium constants were calculated using the Eyring equation for each pH value and temperature. The kinetic constants were fitted to the Arrhenius equation and the set of pair estimates for lnk(0) and the activation energy followed the straight lines that cause the kinetic compensation, with isokinetic temperatures of -10.3 degrees C found for the zero-order adsorption step and 8.4 degrees C for the first-order desorption step. The equilibrium constants were fitted to the Van't Hoff equation and the set of pair estimates for the activation enthalpy and the activation entropy followed the straight lines that cause thermodynamic compensation. The isoequilibrium temperatures were obtained as -11.4 degrees C for the zero-order adsorption step and 7.5 degrees C for the first-order desorption step. As expected, the isokinetic and the isoequilibrium temperatures were very close for each step. The mechanism was concluded to be the same for the ranges of pH and temperature studied. Since all the isokinetic and isoequilibrium temperatures were lower than the working temperature values, the control was concluded to be entropic for all cases. Statistical compensation could be discarded for the zero-order adsorption step but for the first-order desorption step, the compensation was concluded to be as significant as the experimental propagation of errors. (AU)

• Processo FAPESP: 16/18052-5 - +Pro²FOOD: tecnologias emergentes para melhoria de processos e propriedades de alimentos
• Beneficiário: Pedro Esteves Duarte Augusto
• Modalidade de apoio: Auxílio à Pesquisa - Regular