Viscoelastic characterization of solid foods from creep compliance data: application to potato tissues

Abstract

 Two software systems were developed to simplify acquisition and analysis of data describing creep behavior of viscoelastic solid foods and to determine the magnitude of instantaneous elastic compliance, viscoelastic compliances and viscosity associated with Newtonian flow. The first of these systems was used to store information on the experiment, to collect the data generated during the experiment, to present these in real time and to create files containing the experimental data for subsequent analysis. The second system was used to fit data to discrete Kelvin-Voigt models with four, six or eight constants. The systems were tested in the calculation of rheological properties of fresh and cooked potato tissues. A six-element Burgers model containing two discrete Voigt units proved the most suitable for defining tissue creep behavior, suggesting that different structural components could be related to each unit. The instantaneous elastic modulus could be associated with internal cell pressure. Gelatinization of starch and viscoelastic units appeared to reflect the viscoelastic properties of pectic substances and hemicelluloses, respectively.