Figures & data
Figure 1. Dynamic DSC thermal scans for amorphous lactose and lactose/pullulan blends conditioned at several specified moisture content levels.
Figure 2. Effect of moisture content on apparent crystallization enthalpy and crystallization temperature (peak of exotherm) derived from dynamic DSC experiments.
Table 1. Apparent Crystallization (Tc) and Glass Transitions Temperatures (Tg) of Freeze-Dried Lactose and Lactose-Pullulan Systems at Specified Moisture Contents as Derived from the DSC Thermal Curves
Figure 3. X-ray diffraction patterns for freeze-dried lactose stored at specified water activity environments (aw) for different time periods.
Figure 4. X-ray diffraction patterns for freeze-dried lactose/pullulan blend (3:1 w/w) stored at specified water activity environments (aw) for different time periods.
Figure 5. Kinetics of lactose crystallization (X-ray peak intensities at diffraction angle 19°) and the respective Avrami plot of the crystallization data for the lactose/pullulan blend (3:1 w/w).
Table 2. Leveling-off Values for Extent of Crystallization (Peak Intensities at Specified Diffraction Angles) of Different Freeze-Dried Samples Stored at Various Water Activity Environments, and Calculated Rate Constants, ‘Half-time’ for Crystallization and Exponent Values from the Avrami Plots
Figure 6. Representative DSC traces of freeze-dried amorphous samples at specified water contents.
Figure 7. Relationships between water weight fraction and glass transition temperature (Tg) according to the Gordon-Taylor model.
Table 3. Estimated Values of Tg dry solids from the G-T Plots and Coefficients of Determination Using the Specified Values for K
Figure 8. Temperature dependence of the ‘half-time’ (t1/2c) for lactose crystallization in the lactose/pullulan systems according to the WLF formalism.
