The Amino Acid Composition of Wheat Grain as Related to its Protein Content

Abstract

Basic amino acids and protein content of 59 mature grain samples of wheat (Triticum aestivum) have been determined. The samples were obtained in different environmental conditions (fertilization, year of harvesting, location and conditions of wheat growth). Several of them also differed genetically: 12 varieties or cultivars have been studied. The protein content ranged from 9.1 to 20.6 per cent (in g of nitrogen x 6.25 per 100 g of grain dry matter). Whatever the cause of variation of protein content for each amino acid may be, linear relations are pointed out between amino acid percentages of the grain and crude protein content. Thus knowing only the protein content of a wheat grain sample enables to infer its basic amino acid composition. As for the amino acid levels of crude proteins, they are related to protein content by hyperbolic laws. When grain protein content increases, the whole protein of grain becomes much poorer in lysine, their arginine level also drops, whereas their histidine level remains constant