EDIBLE WHEAT GLUTEN FILMS: DEVELOPMENT, MECHANICAL AND BARRIER PROPERTIES AND APPLICATION TO STRAWBERRIES ( Fragaria Ananassa)

Filmes de gluten de trigo foram preparados em diferentes valores de pH e concentracoes de gluten, etanol e glicerol. Seus efeitos sobre permeabilidade ao vapor de agua e oxigenio, solubilidade em agua, forca de tensao e porcentagem de elongacao foram avaliados usando-se a Metodologia de Superficie de Resposta. Menor permeabilidade ao oxigenio foi observada em menores concentracoes de glicerol, gluten e etanol. As propriedades mecânicas foram principalmente afetadas pelas concentracoes de gluten e glicerol e o filme mais resistente foi obtido quando maior concentracao de gluten e menor de glicerol foram utilizadas. Coberturas de gluten de trigo aplicadas em morangos frescos reduziram as perdas de firmeza e de peso durante a estocagem em comparacao com controle nao revestido. Abstract Films from wheat gluten were prepared with different pH values and concentrations of gluten, ethanol and glycerol. Their effects on oxygen and water vapor permeabilities, water solubility, tensile strength and percent elongation at break were evaluated using Response Surface Methodology. The lowest oxygen permeability would be expected at low concentrations of glycerol, gluten and ethanol. The mechanical properties were mainly affected by gluten and glycerol concentrations and the most resistant film was obtained at high gluten and low glycerol concentrations. Wheat gluten coating applied to fresh strawberries reduced weight and firmness losses during storage as compared to uncoated controls.