Study on degradation kinetics of sulforaphane in broccoli extract

The objective of this study was to investigate the thermal degradation kinetics of sulforaphane (SF) in broccoli extract at selected temperatures (60, 75, 82 and 100°C) and pH values (2.2, 3.0, 4.0, 5.0 and 6.0). The results indicated that SF is unstable at high temperatures, but is more heat-stable when present in acidic food products. The degradation rate constants of SF in broccoli extract were lower than those obtained in purified SF. The thermal degradation of SF followed first-order reaction kinetics, and the rate constant increased with increase of temperature and pH values. The rate constant vs temperature relationships, which yield linear Arrhenius plots, were described by a simpler exponential equation, and a mathematical model was developed, using the steady-state kinetic parameters obtained to predict the retentions of SF at various pH values, heating times and temperatures.