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Link Between Mixing Requirements and Dough Strength

¹Present address: 2 Forest View, 23 Shepherdson Place, Isaacs, ACT 2607, Australia. ²Corresponding author. E-mail: woodinga@hotmail.com Phone: +61 2 6286 8549. Fax: +61 2 6286 8549. ³Grain Foods Research Unit, New Zealand Institute for Crop & Food Research Limited, Private Bag 4704, Christchurch, New Zealand. ⁴Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506-2201. ⁵Plant Breeding Institute, Woolley Building, University of Sydney, NSW 2006, Australia.

Industrial bakeries in Australia and New Zealand using the mechanical dough development (MDD) process have experienced undesirable increases in dough mixing requirements. This problem is an unwanted outcome of breeding programs that have endeavored to increase dough strength as a desirable characteristic. Research was undertaken to determine the nature of the link between dough strength and mixing requirements and its relevance to the MDD process across a wide range of wheat lines. Data from three similar trials of 20 wheat lines confirmed the existence of an apparently tight, positive correlation between mixing requirements and dough strength. Although a wide range in genotypes and environments was used, no significant outliers were found, despite the belief that the link between these quality attributes was breakable or at least flexible. This creates a dilemma, as it would be desirable to reduce work input (WI) for economic reasons but not at the expense of loaf quality, which could have a deleterious effect on product marketability. The resultant nexus between mixing requirements, as measured by MDD WI, and dough strength measured by extensigraph resistance to extension (Rmax), appeared to be influenced by the application of nitrogen fertilizer during cultivation, while the nexus between mixing requirements as measured by mixograph development time (MDT) and Rmax, was influenced by other factors associated with crop location. The nexus between farinograph development time (FDT) and Rmax was affected by both location and nitrogen fertilizer application. The rates of increase in WI, MDT, and FDT against Rmax appeared to differ between high molecular weight glutenin subunits (HMW-GS) 5+10 or 2+12 (the Glu-D1 alleles). The Glu-A1 and Glu-A3 loci also played a significant role, indicating that by manipulating them it may be possible to shift or manipulate the nexus between mixing requirements and dough strength. Alleles at these loci appeared to be additive in effect on WI, MDT, and FDT, as well as Rmax.