The winged bean: its nutritional potential

Abstract

The winged bean (Psophocarpus tetragonolobus) has been grown successfully in Ghana. Preliminary work on the raw bean showed the seed contained an active factor which inhibited the activity of pancreatic trypsin. This factor, however, could be successfully destroyed by applying moist heat for 10 minutes at 130ᵒC. The bean contained no urease enzyme activity as known to exist in soybean and other legumes. Unlike soybeans, it has a sweet, nutty taste even in the raw state, and does not exhibit any of the bitter, beany flavour detectable in soybeans. The protein content of the dried seed was found to be 37.3% and its nutritional quality compared favourably with that of soybean in digestibility and composition, with methionine as the limiting amino acid. It contained 18.1% fat with a favourable proportion of polyunsaturated essential fatty acids and a high content of tocopherol (125.9 mg + B per 100g) which can be considered favourable as an antioxidant. Biological assessment gave PER and NPU values comparable to those of soybean. The nutritional potential of winged bean lies in the fact that it can be processed into various products which can safely be incorporated into weaning foods, high protein products and anomal feed. Edible oil can also be obtained from the seed