Background. One of the best ways to present the relationship between phase changes and the stability of food products related to water content and temperature change is a phase diagram. The aim of the presented research was to develop phase diagrams for maltodextrins obtained from native potato starch and acetylated potato starch (E14120) and distarch phosphate (E1412). For this purpose, glass transition curves and freezing curves were determined using the DSC (differential scanning calorimetry) method. As part of the research, an attempt was also made to assess the impact of modification of the original material and the degree of saccharification on the parameters that determine storage stability. Samples with different water activity were obtained by placing dried maltodextrins in an environment with different humidity. The glass transition temperature and freezing temperature were determined using DSC. The results were described using the Gordon and Taylor equation and the Chen equation, and phase diagrams were prepared.
Results and conclusions. The glass transition temperature of anhydrous maltodextrins (T_gs) varied in the range of 131.4 ÷ 172.5 ºC depending on the type of modification of base starch and DE. The glass transition temperature (T_g) of all samples decreased with increasing water activity. The obtained values of the k constant of the Gordon-Taylor model ranged from 4.81 to 5.70, and the parameters of the Chen model varied from -0.334 to -0.123 (parameter B) and from 0.074 to 0.117 (parameter E). The values of unfreezable water X_w‚ (from 0.218 to 0.218 kg of water/kg of sample) and temperature T_m‚ (from -18.6 to -14.9 °C) and T_g‚ (from -42.1 to -22.4 °C) determined using a phase diagram for individual maltodextrin samples depended on DE and the type of modification of base starches. The research performed allows us to conclude that native and modified starch hydrolysates were characterized by different thermal properties, which provides wide possibilities of their use in industrial processes.