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The effect of varying mixing speed (75–400 rev/min) on mixing response (mixing torque, mixing time, mixer blade revolutions, work input, baking quality) has been investigated using a weak and strong commercial flour on a 125 g mechanical dough development (MDD) mixer. Peak torque increases as an exponential function of mixing speed but not as a power law. Number of mixer blade revolutions to peak torque are constant at high speeds, but increase rapidly below about 150 rev/min. Mixing time is also long at slow speeds, but unlike mixer blade revolutions, keeps decreasing as mixing speed increases. Work input increases at low speeds, but stays constant or increases slightly at higher speeds. Baking quality was not significantly affected by mixing speed.

Two field trials using four New Zealand wheat cultivars were undertaken to observe the effects of nitrogen and sulfur fertilization on protein composition, mixing requirements, and dough strength and to compare the results with that observed with a single cultivar, Otane. The results confirmed that adequate sulfur fertilization was necessary to ensure lower dough mixing requirements. The existence of a nexus between mixing requirements and dough strength was confirmed and genotype has significant effects on it. Variation in the content of HMW-GS in the protein corresponded to changes in dough mixing requirement of Otane. Across the four cultivars, dough mixing requirements (mechanical dough development work input and mixograph development time) and dough strength (Extensigraph resistance to extension) depended on different aspects of protein composition. As the content of polymeric proteins increased, MDD work input increased, but mixograph development time decreased, while the effect on Rmax was small. Rmax, however, was more affected by either the content of small monomerics in the flour or the ratio between HMW-GS peak area to total gliadin peak area. The ratio of MDD work input to Rmax was largely explained by the gliadin content of the flour. Thus, depending on the genetic background, it should be possible to adjust dough mixing requirements by modifying overall HMW-GS, LMW-GS, or gliadin content while maintaining dough strength.

The effect on physical dough properties of nitrogen and sulfur fertilizer applied during cultivation was observed in two trials using the bread wheat (Triticum aestivum) cultivar Otane. Wheat flours from both trials were evaluated for physical dough properties under laboratory conditions and also under industrial conditions in the second trial. The laboratory and industrial optimum mechanical dough development (MDD) work input (WI) significantly increased when nitrogen (N) fertilizer was applied without sulfur fertilizer (S) during crop cultivation. With combined N and S fertilization, laboratory and industrial WI remained close to levels for grain grown without fertilizer. Reductions in extensigraph resistance to extension (Rmax) and increases in extensigraph extensibility (Ext) due to S fertilization also were observed. None of the observed changes in WI, Rmax, or Ext due to S fertilization significantly affected end-product quality as measured by loaf volume, crumb grain, and bake score. The nexus between WI and Rmax was weakened by combined N and S fertilization in the first trial, but remained strong in the second trial. Both WI and Rmax increased as N fertilizer and flour nitrogen increased, but at different rates. This observation indicated that by applying N fertilizer to improve dough strength, a disproportionate and disadvantageous increase in WI also resulted, which could be tempered by S fertilization. In this regard, an optimum N:S fertilizer ratio of 3:1 was indicated, although this ratio would be dependent on the balance of available N and S in the soil. Flour N:S ratios <12.5 kept WI to levels desirable in an industrial MDD bakery. Correlations between laboratory WI, mixograph development time (except in the SN1 trial), and farinograph development time were significant. The 125-g MDD mixers appeared to be more responsive when measuring mixing requirements than the mixograph and farinograph to variations in quality due to environmental and agronomic influences and correlated better with industrial performance.

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-D1alleles). The Glu-A1and Glu-A3loci 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.