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Synergistic and Additive Effects of Three High Molecular Weight Glutenin Subunit Loci. II. Effects on Wheat Dough Functionality and End-Use Quality

¹Quality Wheat Cooperative Research Centre Ltd., Locked Bag 1345, North Ryde, NSW 1670, Australia. ²CSIRO Plant Industry, Grain Quality Research Laboratory, PO Box 7 North Ryde, NSW 1670, Australia. ³Department of Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006, 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. Email: F.Bekes@pi.csiro.au.

Understanding the relationship between basic and applied rheological parameters and the contribution of wheat flour protein content and composition in defining these parameters requires information on the roles of individual flour protein components. The high molecular weight glutenin subunit (HMW-GS) proteins are major contributors to dough strength and stability. This study focused on eight homozygous wheat lines derived from the bread wheat cvs. Olympic and Gabo with systematic deletions at each of three HMW-GS encoding gene loci, Glu-A1, Glu-B1, and Glu-D1. Flour protein levels were adjusted to a constant 9% by adding starch. Functionality of the flours was characterized by small-scale methods (2-g mixograph, microextension tester). End-use quality was evaluated by 2-g microbaking and 10-g noodle-making procedures. In this sample set, the Glu-D1 HMW-GS (5+10) made a significantly larger contribution to dough properties than HMW-GS coded by Glu-B1 (17+18), while subunit 1 coded by Glu-A1 made the smallest contribution to functionality. These differences remained after removing variations in glutenin-to-gliadin ratio. Correlations showed that both basic rheological characteristics and protein size distributions of these flours were good predictors of several applied rheological and end-use quality tests.