Composition and protein quality of winged bean (Psophocarpus tetragonolobus)

Abstract

The chemical composition and the protein quality of the winged bean seeds (Psophocarpus tetragonolobus L.DC.), which have increasing importance in tropical regions as a protein and energy-rich food crop, were studied. All varieties showed a high protein content (34.3–40.7% on dry basis) and high oil content (16.4–21.3% on dry basis). Amino acid analysis showed that winged bean contained all amino acids in sufficient quantity, with the exception of the sulphur-containing amino acids. The amino acid content of immature pods was generally lower, and the non-protein nitrogen content higher. The seed showed a high content of hemagglutinins. Thein vivo digestibility was relatively low (71%) compared with other legumes. Protein quality for the non-supplemented winged bean protein, measured by Protein Efficiency Ratio (PER), gave an intermediate value (1.73 vs casein 3.07) compared with other legumes. The apparent digestibility gave the lowest value (72.8%) compared with other legumes.