食品科学・工学とガラス転移

食品の製造・保存との関わり

抄録

The glass transition has attracted great interest from food scientists in recent years, because many phenomena related to food manufacturing and preservation could be systematically explained with a concept of glass transition: for example, food materials maintain their physical and chemical stability better in a glassy state than in a rubbery state. However, it is often difficult to apply the methodology in polymer science to the analysis of glass transition for foods. In this review, the availability of the concept of glass transition in food science and engineering was explained. Such phenomena as reaction rate of non-enzymatic browning, powder caking, and in freeze drying can be described by glass transition.
In addition, the analysis of the glass transition of foods by electrical methods in our research was also reviewed. The dielectric relaxation, i.e., the peak of the dielectric loss, ε”, was observed for glassy gelatin of low moisture contents and ascribed to the local motion of molecules. However, when the ionic conductivity dominated the electrical properties, the ε” peak was masked. For analyzing such a system, the electric modulus, M* was an effective tool.