Sucrose solution freezing studied by magnetic resonance imaging

Magnetic resonance imaging (MRI) is used to non-invasively image both the phase transition of an aqueous sucrose solution undergoing freezing and the structure of the frozen matrix. Ice formation of a 20% w/v sucrose solution was monitored during the freezing process by magnetic resonance imaging (MRI). An original experimental setup was designed with oil as a cooling fluid that allows accurate control of the temperature. The NMR signal intensity of particular sampled volumes was observed during the entire cooling period, from 0 to −50 °C, showing a peak characteristic to a transition before the loss of the signal. Moreover, spatial ice distribution of the frozen matrix was observed by high resolution MRI with an isotropic resolution of 78 × 78 × 78 μm 3. MRI has proved to be a novel technique for determining the glass transition temperature of frozen sucrose solutions, in the concentration range where calorimetric measurements are not feasible.