The denaturation and aggregation of bovine beta-lactoglobulin (50 g/l) at neutral pH was investigated by scanning calorimetry. To cover a wide range of scan rates (2-1200 degrees C/h), we used three different calorimeters : two scanning calorimeters (PE DSC7 and Hart Scientific DSC 4207) and an adiabatic calorimeter. The temperature corresponding to maximum heat capacity, T-p, varied with scan rate. Especially with scan rates below 90 degrees C/h, T-p became strongly dependent on scan-rate, indicating that the reactions involved in the denaturation/aggregation of beta-lactoglobulin are strongly kinetically controlled. With DSC, only one peak was seen at all scan rates, but with decreasing scan rate the peak became more asymmetrical. With the low scan rate of the adiabatic experiment (approximate to 2 degrees C/h) a shoulder at ca. 60 degrees C was observed, clearly indicating that more than one process is occurring. Furthermore, the adiabatic experiment showed that the denaturation/aggregation of beta-lactoglobulin may occur within an infinitely small temperature interval, due to very slow irreversible processes.