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Synergistic and Additive Effects of Three High Molecular Weight Glutenin Subunit Loci. I. Effects on Wheat Dough Rheology

¹Quality Wheat Cooperative Research Centre Ltd., Locked Bag 1345, North Ryde, NSW 1670, Australia. ²Department of Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006, Australia. ³CSIRO Plant Industry, Grain Quality Research Laboratory, PO Box 7 North Ryde, NSW 1670, Australia. ⁴School of Applied Sciences, University of Wolverhampton, Wulfruna St., Wolverhampton WV1 1SB, UK. ⁵CSIRO Plant Industry, GPO Box 1600 Canberra, ACT 2601, Australia. Corresponding author: Phone (Sydney Office): +61 2 9490 8437. Fax: +61 2 9490 8419. E-mail: F.Bekes@pi.csiro.au

The high molecular weight glutenin subunits (HMW-GS) play an important role in governing the functional properties of wheat dough. To understand the role of HMW-GS in defining the basic and applied rheological parameters and end-use quality of wheat dough, it is essential to conduct a systematic study where the effect of different HMW-GS are determined. This study focuses on the effect of HMW-GS on basic rheological properties. Eight wheat lines derived from cvs. Olympic and Gabo were used in this study. One line contained HMW-GS coded by all three loci, three lines were each null at one of the loci, three lines were null at two of the loci and one line null at all three loci. The flour protein level of all samples was adjusted to a constant 9% by adding starch. In another set of experiments, in addition to the flour protein content being held at 9%, the glutenin-to-gliadin ratio was maintained at 0.62 by adding gliadin. Rheological properties such as elongational, dynamic, and shear viscometric properties were determined. The presence of Glu-D1 subunits (5+10) made a significantly larger contribution to dough properties than those encoded by Glu-B1 (17+18), while subunit 1, encoded by Glu-A1, made the least contribution to functionality. Results also confirmed that HMW-GS contributed to strength and stability of dough.