The Amino Acid and Protein Content of Corn as Related to Variety and Nitrogen Fertilization

Abstract

A series of 19 samples of grain corn was analyzed for protein and 18 amino acids. The results revealed that the nitrogen fertilization employed and the variety selected may influence considerably the protein and amino acid content of the corn kernel. The protein content of the samples ranged from 6.8 to 12.0%. The amount of all the amino acids increased with an increase in the protein content of the corn. However, there were considerable differences in the rate of increase among the individual amino acids. The results indicated that with the high-protein corn samples a greater proportion of the protein was zein as compared to the low-protein samples. Nitrogen fertilization increased the protein and amino acid content of corn significantly, with the increase apparently largely in the zein fraction. However, the other proteins were also increased with an increased protein content of corn, as was reflected by the presence of greater amounts of lysine and tryptophan.