The crude protein content amino acid content and amino acid composition of four forage and milling quality winter wheat varieties (‘Magor’, ‘Hunor’, ‘Róna’ and ‘Kondor’) from their samples from five following years (2003, 2004, 2005, 2006 and 2007) were analysed.
The crude protein content of the examined 20 samples of winter wheat varieties were between 11.2 – 14.6 % on dry matter base.
We found that quantity of essential and non essential amino acids rose with increase in crude protein content. The dynamics of quantitative growth was significantly different. We established that, when crude protein content increases for 0.1 %, the essential amino acid content rises by 0.3 g and the non essential amino acid content increases by more than its double, 0.67 g.
By examination of amino acid composition of the protein in relation to crude protein content we found that the crude protein content increased the rate of the non essential amino acids, while the rate of essential amino acids decreased.
To confirm these facts, we analysed the quantity of the limiting amino acid of wheat (lysine) in term of the protein content. We found that, as all the essential amino acids, the quantity of the lysine decreased with increase in crude protein content.
To determine the biological value we used the data of ideal food, worked out by the FAO/WHO, which contents the essential amino acids in optimal quality and quantity. We established that as crude protein content increased, the biological value of the protein decreased.

winter wheat; crude protein content; amino acid composition; essential amino acids; biological value

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia