Assessment of the protein quality of native white floury maize, designated IAPO-13, by amino acid analysis.

摘要

The total protein and amino acid composition of a typical northern adapted (latitude > 45degree C north) variety of native white floury maize, designated IAPO-13, was quantitatively measured and its protein quality was assessed from its FAO/WHO protein digestibility-corrected amino acid scoring pattern. The native IAPO-13 maize produced maize proteins that closely resemble the amino acid composition of floury-2 mutant maize. In IAPO-13 maize lysine, tryptophan, histidine, arginine and aspartic acid were all higher than normal flint CO255 maize, while glutamic acid, leucine, alanine, tyrosine and phenylalanine were significantly lower. The concentration of methionine was higher than in any other maize tested. As a result, the native IAPO-13 maize amino acid profile gives a good balance of total essential amino acids, limited only in lysine, and has a protein digestibility-corrected amino acid score ranging from 37.0 to 40.0% compared to 27.5, 50.6 and 67.0% values found for flint CO255, floury-2 and QPM-C13, respectively. These results indicate that a potentially very useful method for evaluating the protein quality of maize is calculating their protein quality from their amino acid composition.