DisplayTitle

Z-arm and pin-mixers such as the farinograph and mixograph, respectively, are well established torque sensing technologies to evaluate dough mixing requirements, and when conventionally used, impart relatively low and high mixing intensity to dough development. In this study we evaluated a new version of a micro-Z-arm mixer capable of high-intensity mixing and integration of torque data as a function of time, i.e. work input to peak development (WIP), thus facilitating more direct comparison to mixograph results. Objectives were to evaluate effects of increasing Z-arm mixing speed on correlations between key parameters generated by the two mixers, and their prediction by protein fractions underlying gluten strength. Flours milled from a diverse set of 52 HRW genotypes, were analyzed at constant absorption using a 2-g mixograph at 88 rpm and a 4-g micro Z-arm mixer at 63, 100 and 140 rpm. Increasing speed of Z-arm significantly reduced analysis time, and improved relationships between Z-arm mixing (Z) and mixograph (M) parameters. Correlations between Z-dough development time (Z-DDT) and mixograph DDT were R=0.78, 0.81, and 0.85 at 63, 100 and 140 rpm, respectively. Similarly, correlations between Z-WIP and M-WIP were R=0.72, 0.80, and 0.87 at 63, 100 and 140 rpm, respectively. In contrast, Z-stability values at 63 and 100 rpm were poorly correlated to mixograph measures of gluten strength, but correlations improved considerably at 140 rpm for M-DDT (R=0.80) and M-WIP (R=0.74). The relationship between content of HMW glutenin and WIP were very similar for Z-WIP at 100 rpm (R=0.81) and M-WIP (R=0.80). The results indicated that high speed Z-arm mixing and mixograph results were equally effective in discriminating dough strength in a population of bread wheats and were comparably related to the key biochemical component of wheat flour underlying gluten strength.