Glass transition of a meat myofibrillar protein based edible film | [Transition vitreuse d'un film comestible a base de proteine myofibrillaire de viande]
1999
Souza, S.M.A. (University of Campinas (Bresil). Department of Food Engineering) | Sobral, P.J.A. | Menegalli, F.C.
All functional properties of edible films are strongly affected by glass transition temperature. The objective of this work was to study the glass transition of a meat myofibrillar protein based edible film, plasticized by glycerin, as function of the moisture content, by DSC analysis. Edible films were prepared by casting techniques, with freeze-dried myofibrillar protein prepared previously (1 g/100 solution) and glycerin (60 g/100 g of protein). The film solution was heat-treated at 50 degrees/45 min and the pH was maintained at 2.8. After drying, the films were equilibrated under various water activities, between 0.07 and 0.90, at 25 degrees. The glass temperature was determined by two scans. The DSC thermograms showed two glass transitions in the first scan. The first Tg is due to a soluble protein-glycerin portion and the second one is the Tg of a less hydratod protein portion. It was concluded that, the myofibrillar protein edible film is not a real homogenous system. The edible film is flexible because observed Tg of protein system is below room temperature
显示更多 [+] 显示较少 [-]