Relationships between mixograph parameters and indices of wheat grain quality

A 10-gram Mixograph was used to analyse 39 bread wheat cultivars having various agricultural characteristics and origins. Eleven parameters obtained during the first 8 minutes of the mixing procedure were selected using a repeatability analysis in order to investigate variations between genotypes. Several flour protein fractions characterised by their extractability properties and size distributions were quantified. In addition grain hardness, water-extractable arabinoxylan contents and relative arabinoxylan viscosity were also determined and correlated with dough formation during mixing. Dough consistency, as measured by the height of the Mixogram, was correlated with grain hardness, as expressed by the starch damage content and the proportion (%) of flour particles larger than 37.8 mu m. No significant relation was found with the water-extractable arabinoxylan content or the relative arabinoxylan viscosity. The width and height of the Mixogram was related to the proportion of unaggregated proteins before the mixing peak and to polymeric proteins after the dough consistency reached a maximum. The Mixograph proved to be a powerful tool to investigate indices of bread making quality. (C) 1998 Academic Press Limited.