A SIMPLE ANTIBODY-BASED TEST FOR DOUGH STRENGTH .3. FURTHER SIMPLIFICATION AND COLLABORATIVE EVALUATION FOR WHEAT QUALITY SCREENING

An antibody-based method for discrimination of wheat flours or whole m eals on the basis of differences in dough strength (Skerritt 1991b), a s measured by extensigraph maximum resistance for example, was simplif ied for use in large-scale screening to predict dough quality. The maj or modification was the addition of unlabeled antibody to the diluted grain extract being analyzed, which simplified sample handling. It red uced the dilution of the grain extracts being tested and improved the differentiation between flours of different strengths. A method was al so developed for simultaneous extraction and testing of sets of 96 unw eighed whole meal samples. The method was tested in a collaborative tr ial in eight laboratories (none with significant prior immunoassay exp erience) using two separate analyses of a set of 16 flours, including three blind duplicates. Each laboratory reported highly significant co rrelations between color developed in the assay and rheological measur ements of dough strength, such as farinograph development time and ext ensigraph maximum resistance. Good estimates of within- and between-la boratory precision were also obtained, indicating that the method was suitable for quality assessment in wheat breeding.