|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1995 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1994 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Recently it has been revealed that the glass transition temperature (Tg) affects the preservability of foods. In order to apply the concept of glass transition to the processing and preservation of foods, the determinaton of various properties of their components is essential. In this study, protamines which have antibacterial activity were used. The effects of water content and other components on the glass transition of protamines were investigated.
As protamines, salmine and culpeine were used. As the components of model systems, dextran and maltose were employed. Those components were mixed with protamines and freeze-dried. After the water activity of the samples was adjusted, Tg was determined by differential scanning calorimetry (DSC).
From the results of DSC,salmine and culpeine were found to be in glassy state and their Tg were above room temperature. In the region of low water activity, the 10% increase of water cotent caused the decrease of Tg, about 75ﾟC for salmine and about 65ﾟC for culpeine. At the same water content, Tg of salmine-dextran mixture was higher than that of salmine, whereas Tg of salmine-maltose mixture was lower than that of salmine. Therefore, it was concluded that Tg of each component affects Tg of the mixture. The stability of foods can be improved by lowering the water content or by introducing the components having high Tg.