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Ten varieties each of cowpeas (Vigna unguiculata), chickpeas (Cicer arietinum), pigeon peas (Cajanus cajan), and mung beans (Vigna radiata) were assayed for condensed tannin content. Tannin concentrations ranged from 0 to 0.7% for cowpeas and 0 to 0.2% for pigeon peas, with essentially no tannin found in chick peas or mung beans. A less extensive survey found no tannin in four varieties of winged bean (Psophocarpus tetragonobolus), 0.3% in one variety of adzuki bean (Vigna angularis), and 0.1 % in Japanese buckwheat. It is concluded that, of the plants surveyed, the cowpea is the only species likely to contain amounts of tannin that may be nutritionally harmful.

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