Stress relaxation behavior of oat flakes

- Stress relaxation behavior is useful for predicting the textural attributes of oats.
- Two-element Maxwell model was required to describe the viscoelastic behavior of oat flakes.
- The relaxation modulus increased as the moisture content of the oat samples decreased.
- Higher moisture content decreased the resistance of oat flakes to deformation.

It is important to understand the viscoelastic properties of cereals as they affect product texture. Therefore, the stress relaxation behavior of oat flakes was studied using static testing. The oat flakes exhibited linear viscoelastic behavior at strain levels under 2%. The relaxation modulus was directly influenced by the moisture content of the samples; it was low at higher moisture levels. A two-element generalized Maxwell model fitted well to describe the viscoelastic behavior of oat flakes with its high R2 and low RMSE. The first and second stress coefficients (G1andG2) and the second relaxation time component (τ2) of the model generally decreased as the moisture content of the samples increased, which implied that samples showed lower resistance against applied force and relaxed faster with the increase in moisture content. The viscoelastic behavior of oat flakes was a function of both moisture content and temperature. The viscoelastic properties obtained in this study can be used to improve the textural attributes of oat-based products and further utilized in mathematical models describing drying or sorption processes.