A study of factors influencing the water absorption capacity of Canadian hard red winter wheat flour

The nature of variation in water absorption capacity in Canadian hard red winter (HRW) wheat genotypes was studied. Wheat and flour were evaluated for a range of physical and chemical properties including hardness indices, protein content, total and water-extractable arabinoxylan (WEAX) contents and flour particle size by laser diffraction. Absorption, as measured by farinograph (FA) ranged from 54 to 66%. The most highly correlated conventional parameters to FA were protein and WEAX contents, particle size index and starch damage, with correlations ranging from r = 0.37 to 0.56 in absolute values. The volume fractions of large and small flour particles had the highest correlations to FA (r∼0.67). Multivariate regression analysis produced 3 or 4 variable models of FA prediction with R2 ranging from 0.64 to 0.95, depending on the sample population. Results indicated that FA is a complex quality parameter with low values attributable to one or more of low levels of wheat hardness, protein content or AX content, depending on genotype. Improving FA in HRW wheat consistent with hard spring wheat appears to be feasible by increasing concentration of deficient parameters by breeding, especially WEAX which has high heritability and ample variation in the HRW wheat germplasm that was studied.