Degradation kinetics of ergosterol in tomato paste serum

Abstract

Thermal degradation of ergosterol in tomato paste serum was studied at different pH (4.5, 4.3, 3.9, 3.7 and 3.5,) and heating periods (0, 10, 20, 30 and 50 min) over the temperature range of 70 to 95 °C. Analysis of kinetic data suggested a first-order reaction for the degradation of ergosterol with the half-lives of 301.4-36.7, 239.0-33.7, 203.9-29.6, 113.6-29.8 and 83.5-23.7 min for 4.5, 4.3, 3.9, 3.7 and 3.5 pH samples, respectively, between 70 and 95 °C. Temperature dependence of reaction was described by the Arrhenius relationship. Activation energies for 4.5, 4.3, 3.9, 3.7 and 3.5 pH samples were found 20.57, 19.62, 19.07, 12.41 and 11.08 kcal mol-1, respectively, between 70 and 95 °C. © 2007 Springer-Verlag.