Influence of high and low molecular weight glutenins on stress relaxation of wheat kernels and the relation to sedimentation and rheological properties

The stress relaxation behaviour of 36 bread wheat kernel lines was studied using the generalized Maxwell model with 4-exponential terms. The data suggested four relaxation phases, two fast phases at shorter times of 1–10 s (τ1 and τ2) and two slow phases with longer times of ≈50–450 s (τ3 and τ4). The stresses were mainly correlated with kernel mechanical properties. There were differences in spring and stress elements of Glu-A1 null compared to Glu-A1 1 and 2∗. The Glu-B1 and Glu-D1 showed differences in the stresses. Glu-A3 only affected kernel mechanical properties while Glu-B3 showed differences in both quality parameters and mechanical properties. The relaxation times τ3 were high for genotypes with high SDS-sedimentation volume and long mixing time. Genotypes with 45–60 s of τ3 usually had good HMW-GS background and LMW allelic combination generally associated with good quality. As expected, genotypes with short relaxation and mixing times and poor sedimentation volume were samples with Glu-A1 null, Glu-B3 j 1B/1R, and with Glu-A3 e (null). Differences in stress relaxation were found among HMW-GS and LMW-GS alleles specially Glu-3 loci and the differences were related to SDS-sedimentation, mixing and alveograph data.

► Stress relaxation of wheat kernels was studied with the generalized Maxwell model.
► Stress relaxation behaviour of HMW- and LMW-GS in intact wheat kernels was addressed.
► The relaxation times were associated with quality and rheological properties of wheat.
► HMW- and LMW-GS are predominant factors that affect the relaxation stress constants.