Influence of protein segregation on the quality characteristics of Biggar and Genesis Canada Prairie Spring Wheat

Abstract

The influence of protein segregation on the quality characteristics of Biggar, a Canada Prairie Spring Red wheat cultivar, and Genesis, a Canada Prairie Spring White wheat cultivar has been evaluated using 1989, 1990 and 1991 harvest survey samples. Protein segregation had a strong influence on most physical parameters and processing characteristics all three years. However, the slopes of the regression equations of protein content to values for each quality test exhibited heterogeneity between years. For both wheat cultivars, test weight and kernel weight gave consistently high negative correlations to protein content, indicative of less kernel plumpness at high protein content. The resulting lower endosperm content of the higher protein segregates was reflected by higher wheat ash content, and lower flour yield in 2 of the 3 yr. The milling performance of the higher protein segregates was further diminished by consistently high positive correlations of flour grade color to protein content, indicative of diminishing flour brightness. Flour ash content was not related to protein content for either cultivar, indicating that endosperm ash content was not related to protein content. Flour starch damage, which is directly related to kernel hardness, decreased in response to protein content for both cultivars, with the effect being more pronounced for Genesis. Farinograph dough development time, stability and water absorption increased with increasing protein content. Baking water absorption and loaf volume snowed highly significant positive correlations with protein content. However, baking strength index, a measure of loaf volume on a constant protein basis, decreased with increasing protein content for both cultivars in 2 of the 3 yr. These data demonstrate that marketing Canada Prairie Spring wheat at specified protein levels would facilitate specific customer requirements by optimizing particular quality attributes and improving uniformity between commercial shipments. Key words: Wheat, milling, baking, protein, wheat quality