The influence of nitrogen fertilisation on quantities and proportions of 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 extraction/HPLC procedure. The results demonstrate that the quantities of albumins and globulins were scarcely influenced by different nitrogen fertilisation, whereas those of gluten proteins (gliadins, glutenins) were strongly influenced. The effect on gliadins was more pronounced than on glutenins, as well as the effect on major protein types (α‐gliadins, γ‐gliadins, LMW subunits of glutenin) in comparison with minor types (ω‐gliadins, HMW subunits of glutenin). The proportions of hydrophilic proteins (ω‐gliadins, HMW subunits of glutenin) were increased by high levels of nitrogen and those of hydrophobic proteins (γ‐gliadin, LMW subunits of glutenin) were decreased. The degree of the effects on both quantities and proportions of flour protein groups and gluten protein types was strongly dependent on the variety. © 1998 SCI.