Equibiaxial extensional deformation and stress relaxation of glycerol plasticized wheat gluten at different concentrations

The aim of the present work has been to study the equibiaxial extensional deformation of glycerol plasticized moisture-containing gluten (MG) with different MG volume fractions ranging from 0.56 to 0.75 under lubricated squeezing flow at room temperature. The hyperelastic model with a strain energy potential of the Mooney–Rivlin form is applied to describe the biaxial stress as a function of biaxial strain at low strains. The initial shear modulus as a function of MG volume fraction reveals a particle network of gluten. Analysis of the relaxation modulus at biaxial strain 0.7 on the basis of the Kohlrausch–Williams–Watts (KWW) model reveals that decreasing volume fraction of MG increases the width of the distribution of relaxation times as well as the average relaxation time of wheat proteins.