Thermal degradation kinetics of l-carnitine

The objectives of this work were to study the thermal degradation kinetics of l-carnitine and to develop a procedure for thermal inactivation kinetics determination from dynamic temperature profile experiments. Experiments were conducted at isothermal conditions in a temperature range from 80 to 130 °C. Remaining l-carnitine concentration was measured at predescribed time intervals at each temperature tested. The kinetic parameters DTref and z were determined after the first order kinetic behavior of l-carnitine thermal inactivation was verified. Furthermore, l-carnitine concentration data were collected during a non-isothermal experiment and the DTref and z values were determined through appropriate methodology. From the isothermal experiments, the parameters D120°C and z were calculated equal to 50.4 min and 30.8 °C, respectively. Similar values (D120 °C = 52.0 min and z = 31.8 °C) were obtained from the measurements during the dynamic temperature profile experiment. Based on the agreement between the parameters estimated using isothermal and non-isothermal temperature profiles, and given the reduced number of experimental data required by the latter approach, kinetic parameter estimation from experiments at dynamic conditions is recommended.