Effect of nitrogen fertilisation on protein content, total fatty acid content and composition of barley (Hordeum vulgare L.) grains

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Abstract
The impact of N‐fertilisation level on protein content, total fatty acid (TFA) content and major fatty acid composition of barley grains (cv. Eldorado), grown in a replicated field trial, was investigated. Increasing amounts of N‐fertiliser, applied at several stages during the growing season, resulted in a higher protein content and a very slightly lowered TFA content in the grains. Protein and TFA contents were negatively correlated (r=‐0.4685). Minor changes of fatty acid composition were found in the decrease of the oleic acid (C18:1) proportion (r=‐0.8376) and in the increase of the palmitic acid (C16:0) proportion (r=0.7273). The stearic acid (C18:0) and the linoleic acid (C18:2) proportions were also affected, however, no significant linear correlations with the total N‐fertiliser level were obtained. The slow increase in the linolenic acid (C18:3) proportion (r=0.5674) was too small, compared to the residual variance, to be significant. TFA content was positively (PP<0.001) with the palmitic acid proportion. These data suggest that the application of higher amounts of N‐fertiliser slightly decreases the total fatty acid content of barley grains, probably due to a decreased synthesis of oleic acid, precursor of the unsaturated C18 fatty acids. The result is a relative increase in palmitic acid.