Comparison of viscoelastic properties of gluten from spelt and common wheat

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 G(N)(0), the central frequency of the upper dissipative loss peak omega(0), and the spread parameter n. Steady state compliance J(e)(0) and Newtonian viscosity eta(0) 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) supercript stoprad/s, revealing the lower dissipative peak loss. The width of the viscoelastic plateau tau(0)(m)/tau(0) 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.