A A C C   2 0 0 0   A n n u a l   M e e t i n g

The objective of the work was to determine ability of the different gluten proteins to predict the mixing and baking properties of wheats. The plant material consisted of 20 wheat varieties or breedings lines at two levels of N fertilizer grown in two years. The compostion of the HMW and LMW glutenin subunits and the Gli-1 encoded gliadin blocks were identified by electrophoretic methods. The content of gluten macropolymer and sedimentation volumes were analyzed. The mixing properties of the flours were determined by mixograph and farinograph operated at 63 and 126 rpm. Experimental baking of hearth loaves was carried out using a small-scale procedure. The results from grain and flour testing and from the baking trials were treated independently for each year due to very different climatic conditions during the two growing seasons. The results were analyzed statistically by Partial Least Square (PLS) regression. The contribution of the various gluten proteins and their properties to predict the bread loaf properties, as well as the dough mixing properties is discussed. Good prediction models for SDS sedimentation volumes were obtained. The predicions models obtained for the bread loaf properties were not as good as those for the SDS sedimnetation volume. About two thirds of the variance in loaf volume, loaf weight and form ratio could be explained by the HMW and LMW glutenin composition togehter with the flour protein content. Including the mixing properties in the models did not improve the prediction models for the bread loaf properties when the models already contained the glutenin composition.