1. The proximate composition, amino acid composition and the quality of the protein of the African locust-bean (Parkia filicoidea Welw.) seed, seed with pulp, and various processed forms, with or without amino acid supplementation, were assessed.
2. The crude protein content of the locust-bean seed was 303 g/kg and the crude fibre content was 121 g/kg.
3. The seeds contained (mg/g protein): 67 lysine, 6.1 methionine and 8.9 tryptophan.
4. Diets containing 100 g protein/kg supplied by the seed did not support growth in rats, demonstrating that the protein was of poor quality.
5. Utilization of the protein of locust-bean seeds was improved by cooking, and by removal of the tough leathery outer testa of the seeds.
6. Supplementation with methionine alone resulted in positive growth and a very substantial increase in protein values.
7. Supplements of methionine and tryptophan caused further improvement in protein quality and increased the growth of rats to almost that obtained with whole egg.