Cereal Chem 65:271-277   |  VIEW ARTICLE

The Amino Acid Composition of Whole Sorghum Grain in Relation to Its Nitrogen Content.

J. Mosse, J.-C. Huet, and J. Baudet. Copyright 1988 by the American Association of Cereal Chemists, Inc. 

Sorghum grains (12 samples from seven different lines or hybrids) with total nitrogen, N, content ranging from 1.5 to 3 g/100 g grain dry matter were accurately analyzed for their amino acid composition from six different hydrolysates per sample. Amino acid levels in grain increased as linear functions of N, with correlation coefficients close to one for most amino acids regardless of sorghum genotype or phenotype. As a result, the amino acid composition of any grain sample of normal sorghum can be predicted as its N. Amino acids in grain protein changed as hyperbolic functions of N, which increased for alanine, leucine, isoleucine, phenylalanine, and glutamine plus glutamic acid, remained constant for serine, tyrosine, tryptophan, and asparagine plus aspartic acid, and decreased for the other amino acids. The nonprotein-to- total nitrogen ratio remained practically constant and close to 5%, and the nitrogen-to-proten conversion factor (kA) was close to 5.81 within the N range investigated. The results also showed that the composition of storage proteins accumulated in sorghum grain remained constant, with the rate of deposition of kafirins roughly 1.5 times that of glutelins.