Assessment of the Protein Quality of 15 New Northern Adapted Cultivars of Quality Protein Maize Using Amino Acid Analysis

• Published in: Journal of agricultural and food chemistry 2000-11, Vol.48 (11), p.5351-5361
• Main Authors: Zarkadas, Constantinos G, Hamilton, Robert I, Yu, Zi Ran, Choi, Victor K, Khanizadeh, Shahrokh, Rose, Nicholas G. W, Pattison, Peter L
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Amino Acids - analysis; Biological and medical sciences; Dietary Proteins; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - genetics; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Generalities. Production, biomass, yield. Quality; Genes, Plant; Humans; Nutritional Requirements; Plant Proteins - chemistry; Plant Proteins - genetics; Species Specificity; Transcription Factors - chemistry; Transcription Factors - genetics; Zea mays - chemistry; Zea mays - genetics
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf000374b

Amino acid determinations were carried out on 15 new northern adapted cultivars of quality protein maize (QPM) containing opaque-2 modifier genes to ascertain whether their amino acid scoring patterns could be used to select high-lysine QPM genotypes and to assess their protein quality. Total protein in these cultivars ranged from 8.0 to 10.2% compared to two commercial maize varieties, Dekalb DK435 (7.9%) and Pioneer 3925 (10.3%). Four of these QPM genotypes, QPM-C26, QPM-C21, QPM-C79, and QPM-C59, contained high levels of lysine (4.43−4.58 g of lysine/100 g of protein), whereas the remaining varied from 3.43 to 4.21 g of lysine/100 g of protein, compared to Dekalb DK435 and Pioneer 3925, which contained 2.9 and 3.1 g of lysine/100 g of protein, respectively. Although lysine is the first limiting amino acid in QPM inbreds, the high-lysine QPM genotypes may supply ∼70.2−72.6% of human protein requirements, compared to 46.2% for Dekalb DK435 and 50.1% for Pioneer 3925, 55−63% for oats, and 59−60.3% for barley. Northern adapted QPM genotypes may have the potential to increase their lysine content even further, either by an increase in specific high-lysine-containing nonzein proteins, such as the synthesis of factor EF-1a, or by a further reduction in the 19 and 22 kDa α-zein in the endosperm or both. This knowledge could assist maize breeders in the selection of new high-performance QPM genotypes with improved protein quality and quantity. Keywords: Maize; quality protein maize; QPM; opaque-2 maize; QPM performance; protein quality; amino acid composition; amino acids; essential amino acids; corrected amino acid score