Dielectric properties of frozen maltodextrin solutions with added NaCl across the glass transition

The change in the dielectric properties of frozen 200 g kg^-1 maltodextrin solutions upon warming has been recorded using a capacitance meter and a dielectric thermal analysis instrument. The capacitance and permittivity increased by several orders of magnitude after melting, and higher values were obtained at a higher measurement frequency or with added NaCl, while a marked increase (labelled Trise) was seen close to the glass transition temperatures measured by differential scanning calorimetry. The transition temperatures shifted to more negative values by 4-6 °C upon the addition of 0.1 mol kg^-1 NaCl, consistent with the freezing point depression of the freeze-concentrated solutions.