Effect of β-glucans on viscoelastic properties of barley kernels and their relationship to structure and soluble dietary fibre

The stress relaxation behaviour of barley kernels with differences in β-glucan was studied using the generalized Maxwell model for explaining the differences in quality. The relaxation moduli show that cultivar significantly affected the relaxation times (τ₂ and τ₃) and compressional viscosity (η_E2 and η_E3) of the 3 Maxwell elements and the pure elastic component (E₀). These data were twice as high in cultivars with high β-glucans compared to low β-glucans. Protein and malt extract, as well as β-glucan, showed similar patterns to the corresponding cultivars from the same locations. Malt extract was correlated with both insoluble fibre (−0.71; P < 0.0007) and total fibre (−0.66; P < 0.006). High β-glucan cultivars presented relatively high soluble fibre, wort viscosity and presented higher relaxation times. Soluble fibre and the wort viscosity were correlated with relaxation times τ₁, τ₂, τ₃. Also, β-glucans were correlated with τ₃ and viscosity η_E3. The overall importance of the effect of β-glucans on viscoelasticity, malting and food quality as shown in this investigation is in agreement with earlier investigations.