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Effects of Incorporated Glutenins on Functional Properties of Wheat Dough

¹Quality Wheat Cooperative Research Centre Ltd., Locked Bag No. 1345, North Ryde, NSW 1670, Australia. ²Corresponding author. Phone: 61 2 9351-7141. Fax: 61 2 93517060. E-mail: suthay@mech.eng.usyd.edu.au ³Plant Breeding Institute, The University of Sydney, NSW 2006, Australia. ⁴CSIRO Plant Industry, Grain Quality Research Laboratory, North Ryde, NSW, 1670, Australia.

The development of reduction-oxidation methods to open the native gluten polymer, incorporate monomers, and repolymerize the modified polymer, has allowed new types of investigation of the effects of glutenin subunits on dough characters. These methods were used to incorporate bulk high molecular weight glutenin subunits (HMW-GS) and bulk low molecular weight glutenin subunits (LMW-GS) from four cultivars into the parent flours to modify the HMW-GS-to-LMW-GS ratio. In addition, the glutenins from the four cultivars were added to a single base flour of differing glutenin subunit composition. Finally, HMW-GS 7, 8, 5, and 10 were incorporated singly and in pairs into two base flours. The mixing time, peak resistance, maximum resistance to extension, and loaf height increased with increases in HMW-GS-to-LMW-GS ratio. There was a decrease in resistance breakdown observed with increase in HMW-GS-to-LMW-GS ratio. The maximum resistance to extension slightly increased with increases in HMW-GS-to-LMW-GS ratio (strongly in cultivar Hartog). Dough extensibility decreased with increase in HMW-GS-to-LMW-GS ratio (except in Osprey derivative). In the incorporation studies of single and paired glutenin subunits, HMW-GS 5+10 gave a synergistic effect increasing mixing time, maximum resistance to extension, and loaf height as compared with HMW-GS 5 or 10 separately. In contrast, HMW-GS 7+8 showed an additive effect and HMW-GS 7 incorporated separately had a higher mixing time, maximum resistance to extension, and loaf height than those of HMWGS 7+8 and HMW-GS 8.