Once the sample was subjected to water activity values higher than RHc, the glass
transition occurred, that is the inflection point in the curve was observed. This
resulted in high levels of hysteresis. Subsequent desorption and adsorption cycles
did not exhibit an inflection point at the RHc, which indicated that once the glass
transition has occurred, simply drying the sample did not return it to the
amorphous glassy state. Further cycles also exhibited steadily decreasing hysteresis