THE INFLUENCE OF NITROGEN-FERTILIZATION ON QUANTITIES AND PROPORTIONSOF DIFFERENT PROTEIN TYPES IN WHEAT-FLOUR

The flours of 13 wheat varieties grown at different levels of nitrogen fertilisation were characterised by the quantitative determination of flour protein groups and gluten protein types using a combined extrac tion/HPLC procedure. The results demonstrate that the quantities of al bumins and globulins were scarcely influenced by different nitrogen fe rtilisation, whereas those of gluten proteins (gliadins, glutenins) we re strongly influenced. The effect on gliadins was more pronounced tha n on glutenins, as well as the effect on major protein types (alpha-gl iadins, gamma-gliadins, LMW subunits of glutenin) in comparison with m inor types (omega-gliadins, HMW subunits of glutenin). The proportions of hydrophilic proteins (omega-gliadins, HMW subunits of glutenin) we re increased by high levels of nitrogen and those of hydrophobic prote ins (gamma-gliadin, LMW subunits of glutenin) were decreased. The degr ee of the effects on both quantities and proportions of flour protein groups and gluten protein types was strongly dependent on the variety. (C) 1998 SCI.