Nutritional quality is a lever for the adoption of new varieties. This study aimed to assess the protein quality of 29 cowpea genotypes for breeding purposes. The collection includes 4 local and donor parental varieties, 10 and 11 progenies of F7-30 and F8-38 families, and 4 dual-purpose varieties. Crude protein and protein-soluble fractions of cowpea grains were determined using the methods of Kjeldahl, Osborne, and Campbell, respectively. Amino acid content was quantified using high-performance liquid chromatography. The descriptive analysis shows high intra and inter-familial trait variability among genotypes. Protein contents varied from 25.5% to 35.86%. The main protein fractions were albumin (24.36–73.34 g/100 g protein) and glutelin, followed by globulin and prolamin. Glutamine/glutamic acid, asparagine/aspartic acid, and phenylalanine + tyrosine were prevalent. Methionine + cysteine was the most limiting amino acid. However, apart from CWS-F7-30-9a, CWS-F7-30-7a, and CWS-F8-38-50, all investigated genotypes meet the requirements of all essential amino acids (EAAs) as recommended by FAO/WHO/UNU adults and 2–5 year olds. The genotypes had a mean predicted protein efficiency ratio of 3.68, making them excellent protein sources. This study identifies genotypes with high protein, good EAA profile, and high protein quality for breeding programs and other specific usages.
Key words: Vigna unguiculata, lines, varieties, amino acids, soluble proteins, protein quality
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