Thermal properties of frozen water in the native and amorphous starches with various hydration degrees.

The melting process of frozen water (FW) in various starches (rice, wheat, potato) that have crystal lattices of A- and B-type has been studied by means of differential scanning calorimetry (DSC). The dependences of the melting temperature (Tm) and heat (Qm) of FW on the size of the water clusters forming in starches with various humidity (the so-called size effect) and on conformational changes of starch molecules upon the destruction of native starch crystals (starch amorphization) have been considered. It has been found that in the native starches with low humidity (<35%) the Tm of FW lies below 0 °C and decreases with the decrease of their humidity.

[Formation and melting of ordered structures in denatured myoglobin with differing water content: differential scanning calorimetry method].

The possibility of superstructure formation in denatured globular proteins has been studied through the temperature dependence of the absolute values of heat capacity in the myoglobin-water system with water content from 80 to 25% in the temperature range 20-160 degrees C. For all the composition range studied it is found that after the denaturation of myoglobin the new regular structures with reversible melting are formed. These structures are similar in properties to the thermotropic gels in concentrated myoglobin solutions.