Improvement of protein quality in cereals

Abstract

Protein quality is defined related to the uses of the grain for breadmaking, malting or feeding. Feeding quality, the subject of this review, is limited by the proportions of the limiting essential amino acids, notably lysine. This in turn is determined by the amino acid compositions of the nitrogenous fractions of the grain. The chemical characteristics and genetic control of the free amino acid, storage protein, and structural and metabolic protein fractions are described and their contributions to grain quality defined. Strategies and progress in improvement of the three fractions are examined for the major cereal crops. Some promising areas of research are outlined in which the storage protein genes are modified by genetic manipulation techniques.