MODIFICATION OF PHYSICAL AND BARRIER PROPERTIES OF EDIBLE WHEAT GLUTEN-BASED FILMS

Edible films were produced from wheat gluten-based film-forming soluti ons. One film was produced as a control. Other types came from subject ing control films to three different soaking treatments. Three additio nal films were also produced by modifying the control film-forming sol ution. For all films, selected physical properties and permeability to water vapor and oxygen were measured. Comparisons indicated possible ways to improve the control film. All films were good oxygen barriers but limited water vapor barriers. Films containing hydrolyzed keratin had lower oxygen permeabiliiy (83%) and lower water vapor permeability (23%). Films containing mineral oil had lower water vapor permeabilit y (25%). Films soaked in calcium chloride solution and in buffer solut ion at the isoelectric point of wheat gluten had higher tensile streng th (47 and 9%, respectively) and lower water vapor permeability (14% a nd 13%, respectively). Addition of a reducing agent increased tensile strength (14%). Soaking in lactic acid solution did not improve the st andard film properties.