Ken Fukami

Prediction Approach to the Glass Transition Temperature of Amorphous Carbohydrate Polymer

Most of carbohydrate polymers exist, at least partially, in an amorphous state, and thus, glass transition occur during dehydration/rehydration and cooling/heating processing. Since various physical properties are changed drastically by the glass transition (Levine and Slade 1988; Roos 1995; Le Meste et al. 2002), it is important to understand the glass transition temperature (Tg).

Effect of Water Content on the Glass Transition Temperature of Calcium Maltobionate and its Application to the Characterization of Non-Arrhenius Viscosity Behavior

To understand the fundamental physical properties of calcium maltobionate (MBCa), its water sorption isotherm, glass transition temperature (Tg), and viscosity (η) were investigated and compared with those of maltobionic acid (MBH) and maltose. Although amorphous maltose crystalized at water activity (aw) higher than 0.43, MBCa and MBH maintained an amorphous state over the whole aw range. In addition, MBCa had a higher Tg and greater resistance to water plasticizing than MBH and maltose. These properties of MBCa likely originate from the strong interaction between MBCa and water induced by electrostatic interactions. Moreover, the effects of temperature and water content on η of an aqueous MBCa solution were evaluated, and its behavior was described using a semi-empirical approach based on a combination of Tg extrapolated by the Gordon-Taylor equation and a non-Arrhenius formula known as the Vogel–Fulcher–Tammann equation. This result will be useful for understating the effect of MBCa addition on the solution’s properties.