THE PROBLEM OF PROTEIN QUALITY IN MAIZE

Summary

The poor nutritional quality of maize protein is attributable to the zein fraction, which is very low in lysine and tryptophan, the first limiting amino acids in maize. The protein content of ‘normal’ maize can be increased by correct soil fertilization practices and by breeding but not without a reduction in biological value due to a disproportionate increase in zein relative to non-zein fractions. The discovery that the o₂- and fl₂- mutant genes alter the protein distribution pattern with a marked reduction in the proportion of zein, has made possible the production of high-lysine, high-tryptophan lines with a marked improvement in the quality of the maize proteins. Exploitation of this finding could lead to an improvement in the nutrition of the low-income population groups in this country.