EFFECTS OF NITROGEN-FERTILIZATION AND MATURATION CONDITIONS ON PROTEIN AGGREGATES AND ON THE BREADMAKING QUALITY OF SOISSONS, A COMMON WHEAT CULTIVAR

Formation of storage proteins and their aggregation in response to ava ilable nitrogen and maturation conditions were investigated for the Fr ench wheat cultivar Soissons. N-fertilization level greatly influences the accumulation of the different classes of storage and metabolic pr oteins by modifying the relative composition of the protein pool, whic h can be expressed by a decrease of the ratio of glutenins to gliadins and also by variations in baking strength. Changes in glutenin conten t, high molecular weight glutenin subunits (HMW-GS), and aggregates we re monitored by nitrogen determination, sodium dodecyl sulfate (SDS) p olyacrylamide gel electrophoresis, size-exclusion high-performance liq uid chromatography, and reversed-phase high-performance liquid chromat ography. Whereas the composition in HMW-GS remained unchanged, the agg regation level of glutenic polymers developed differently depending on the maturation conditions. These aggregation variations are discussed in connection with the specific contribution of some HMW-GS to the fo rmation of both soluble and insoluble SDS-glutenic aggregates and also with baking strength response.