Comparison of viscoelastic properties of gluten from spelt and common wheat

Abstract

Rheological properties of gluten from spelt and common wheat were studied. The mechanical spectra of gluten samples were registered over a frequency range of 0.001–200 rad/s. Retardation tests were performed to keep all measurements within a linear regime. The mechanical spectra were fitted with Cole–Cole functions to calculate the viscoelastic plateau modulus GN0, the central frequency of the upper dissipative loss peak ω0, and the spread parameter n. Steady state compliance Je0 and Newtonian viscosity η0 were determined from the retardation tests results. Recovery data were converted from time to frequency domain using the Kaschta method and combined with dynamic data; this enabled the extension of the gluten mechanical spectra down to 10−6 rad/s, revealing the lower dissipative peak loss. The width of the viscoelastic plateau τm0/τ0 was calculated, and substantial qualitative and quantitative differences were found in spelt and common wheat gluten. All differences in gluten rheological properties were related to spelt and common wheat flour baking quality and protein composition.