Influence of Low Molecular Weight Glutenins on Viscoelastic Properties of Intact Wheat Kernels and Their Relation to Functional Properties of Wheat Dough

The mechanical and viscoelastic properties of intact wheat kernels of 36 wheat cultivars differing in low molecular weight glutenin subunit (LMW-GS) composition (loci Glu-A3, Glu-B3, and Glu-D3) were evaluated using load-compression tests. Comparison among genotypic groups representing Glu-3 allelic variants showed that groups representing the alleles Glu-A3 b, c, and d; Glu-B3 d, g, and h; and Glu-D3 a, b, and d, had harder kernel texture, higher kernel elastic work and larger gluten strength-related parameters than those possessing alleles Glu-A3 e; Glu-B3 f, i and j (translocation 1B/1R); and Glu-D3 d. Modulus of elasticity (stress to strain ratio) showed low values (111.9-168.8 MPa) for allelic groups possessing poor elastic properties (Glu-A3 e; Glu-B3 f, i, and j; and Glu-D3 d), and high values (179.8-222.6 MPa) for allelic groups possessing high kernel elastic properties (Glu-A3 b c, and d; Glu-B3 d, g, and h; and Glu-D3 a, b and c). The highest values for gluten strength-related parameters (SDS-sedimentation, dough mixing time, and dough strength [W]) corresponded to allelic groups Glu-A3 d; Glu-B3 d and g; and Glu-D3 d, while the lowest corresponded to Glu-A3 e and Glu-B3 j. No significant differences were observed among groups with regard to gluten extensibility parameters; however, the highest P/L value (least extensibility) corresponded to Glu-B3 j, which indicates presence of 1B/1R translocation. Except for the Glu-B3 j (translocation 1B/1R) allele, which presented more variation within samples, a general relationship between kernel viscoelastic properties and dough viscoelastic properties was observed; samples showing higher elastic work to plastic work ratio (E/P) tended to possess better gluten strength than cultivars with low E/P ratio.