THERMOPLASTIC PROPERTIES OF FISH MYOFIBRILLAR PROTEINS - APPLICATION TO BIOPACKAGING FABRICATION

Thermoplastic properties of fish myofibrillar proteins were studied by dynamic mechanical thermal analysis. Important changes in dynamic mec hanical properties, observed when the temperature was increased, were associated with the glass transition of fish myofibrillar proteins. Th e glass-rubber transition was observed between 215 and 250 degrees C f or the dry material. Addition of water or hydrophilic plasticizers (su crose and sorbitol) induced large decreases in the glass transition te mperature. The depressive effect of water content on the glass transit ion temperature is described with non-linear relationships. The thermo dynamic theory of glass transition (i.e. the Couchman-Karasz equation) was adequate to describe partially the plasticizing effect of water o n the myofibrillar proteins. Glassy or foamed biopackagings were obtai ned by a thermomoulding technique when the process temperature was hig her than the glass transition temperature at a given moisture content. (C) 1997 Elsevier Science Ltd.