THERMAL-PROPERTIES OF FISH MYOFIBRILLAR PROTEIN-BASED FILMS AS AFFECTED BY MOISTURE-CONTENT

Myofibrilar protein-based films were developed from a film-forming sol ution based on fish mince. The thermal properties of these films were characterized by dynamical mechanical thermal analysis and by differen tial scanning calorimetry as a function of their water content. During a temperature increase, the films produced sudden changes in mechanic al property and specific heat, which are classicaly associated with th e glass-rubber transition for amorphous materials. The glass transitio n was about 20 degrees C broad. Increasing the film water content invo lved a non-linear decrease in glass transition temperature. The thermo dynamic theory of the glass transition (i.e. the Couchman-Karasz equat ion) was inadequate to describe fully the plasticizing effect of water on the films. (C) 1997 Elsevier Science Ltd.