EFFECTS OF POLYOLS AND SUGARS ON THE STRUCTURE OF WATER IN CONCENTRATED GELATIN GELS AS STUDIED BY LOW-TEMPERATURE DIFFERENTIAL SCANNING CALORIMETRY

Phase-transition temperatures, glass-transition temperatures, melting temperatures, pel-sol transition temperatures in differential scanning calorimetry heating curves of gelatin solutions with and without vari ous sugars and polyols quenched by liquid nitrogen were studied. Both sugars and polyols added to concentrated gelatin solutions shifted the glass-transition temperatures to lower temperatures, and it was attri buted to the increase of unfreezable water which acts as a plasticizer , The mechanisms of the increase in unfreezable water, however, seem t o be different for sugars and polyols; sugars increase unfreezable wat er by increasing the number of junction zones which hold unfreezable w ater, while polyols by themselves increase the amount of unfreezable w ater.