Properties of thermally-treated wheat gluten films

Effects of thermal treatments on selected properties of wheat gluten film were studied. Films were cast from heated alkaline aqueous solutions of wheat gluten, ethanol and glycerin and subsequently heat treated at 65, 80, or 95 degrees C for 2, 4, 6, 12, 18, or 24 h. Water vapor permeability (WVP), Hunter L, a and b values, tensile strength (TS) and elongation at break (E) were determined and compared with untreated film (control). Significant reduction in WVP of film occurred with increasing curing temperature and exposure time. Hunter L value (whiteness) decreased, whereas a (redness) and b (yellowness) values increased with increasing heat treatment temperature and exposure time. Also, an increase in TS and a decrease in E were present with increasing treatment temperature and exposure time. (C) 1997 Elsevier Science B.V.