6. Handling and storage of cowpea vigna unguiculata (l.) Walp. As a leaf vegetable.
Trop. Agric. (Trinidad), 69, No. 2, 1992, p. 197-199
This study examines the effects of temperature and package ventilation on the storage life of fresh cowpea leaves.
Cowpea, Vigna unguiculata (L.) Walp., is a popular leaf vegetable and grain legume in many parts of Africa.
Most commonly, leaves are served boiled to accompany a starchy porridge; fried and fresh in relish are other popular methods.
The cowpea has many desirable horticultural characteristics not usually associated with leaf vegetables. It is an efficient nitrogen-fixing, heat- and drought-tolerant legume. A single planting yields leaves, immature pods, and immature and mature seeds. Cooked leaves contain two-thirds the protein, seven times the calcium, three times the iron, half the phosphorus, eight times the riboflavin, five times the niacin and several hundred times the asorbic acid and beta-carotene of the cooked seed. Amino acid composition indicates that cowpea leaf protein is superior to seed protein.
Drying boiled or blanched cowpea leaves is a widespread method of preservation.
"Vita 7", a erect cowpea cultivar with short trailing vines was selected for the study.
It was released by the International Institute for Tropical Agriculture, Ibadan, Nigeria, for its high yields and adaptability throughout Africa and Brazil.
Storing cowpea leaves in shaded, closed polythene bags or any container with minimal ventilation at ambient temperature increases storage life of cowpea leaves compared with open storage. Minimal cooling lengthens the period of storage, but temperatures below 15 C will induce chilling injury. If leaves are cooked immediately after removal from cold storage as would be expected if leaves were stored in the home, chilling injury might not be detrimental. Leaves in cold storage below 15 C at the whole sale or retail level would not remain edible after purchase.
Additional research should determine if ventilation greater than the closed bag but less than the next level tested (25 times greater) can extend the storage life and reduce the development of off-odours at high temperatures due to reduced oxygen levels.
1186 92 - 8/47
Africa, Niger, dry season, gardening projects, Lutheran World Relief
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