In this study, we followed in situ changes in the infrared spectrum at diff
erent conditions of pressure and temperature. Cooperative changes were obse
rved when temperature or pressure was increased. Plotting the midpoints of
cooperative transitions in a pressure-temperature plane results in an outli
ne similar to the stability curve of proteins. We can assume that it is the
first time that the pressure-temperature dependent gelation diagram is det
ermined in situ for starch.