Protein content and amino acid composition in seed of bread wheat (Triticum aestivum L.)

The aim of this study was determination of protein content and amino acid composition in seeds of bread wheat, with particular focus of evaluation essential amino acids (EAAs). For analysis used flour samples of grained seed of 10 wheat variety, which selected in different breeding center (in Novi Sad and Kragujevac, Serbia). Kjeldahl method was used for determination of nitrogen (N) contents which value multiplied with coefficient 5.7 for computing protein content (protein contents = 5.7 x % N contents). Amino acids analyses of wheat samples were performed by ion exchange chromatography, followed by the ninhydrin colour reaction and photometric detection at 570 nm and 440 nm (for proline). The results showed that the mean protein content for wheat varied from the lowest value 10.24% in Ljubicevka to the highest 14.21% in Fortuna variety. The mean contents (g 100 g-l protein) of nonessential amino acids (NEAAs) were aspartic acid 5.42%, serine 4.23%, glutamic acid 18.51%, proline 12.18%, glycine 4.17%, alanine 3.64%, tyrosine 2.52%, arginine 5.02%, while mean contents of essential amino acids (EAAs) were threonine 2.86%, valine 4.52%, methionine 1.28%, isoleucine 3.87%, leucine 5.87%, phenylalanine 4.62%, histidine 2.46%, lysine 2.91%. The wheat variety contained relatively high concentration of the most deficient EAAs. The variety Ljubicevka contained relatively high concentration of the most deficient EAAs (threonine, valine, leucine, lysine,). The highest value (29.31 g 100 g-l protein) of total essential amino acids (TEAA), 59.79 g 100 g-l protein of total nonessential amino acids (TNEAA) as well as the highest value (90.35 g 100 g-l protein) of total amino acids (TAA). Obtained results provide variability of wheat variety on the base of amino acid contents and indicate reliable variety for selecting desirable parents in breeding program for improving nutrient quality.