Description

A poster presented at the 2012 Global Pulse Researchers Meeting, Kigali, Rwanda- “Transforming Grain-Legume Systems to Enhance Nutrition and Livelihoods”. Abstract: Sixty diverse Vigna unguiculata (Cowpea) varieties were screened for polyphenols, tannins, flavonoid composition, and antioxidant activity, to associate these beneficial attributes with seed phenotypic traits (seed coat color, texture and plant maturity). Significant diversity was observed in the amount of polyphenols (2.05 to 13.8 mg gallic acid equivalents/g) and condensed tannin (0.2 to 10.8 catechin equivalents/g). Antioxidant activity values range from 25 to 85 Trolox equivalents, TE/g (oxygen radical absorbance capacity, ORAC) and 5 to 143 TE/g (Trolox equivalent antioxidant capacity, TEAC). Highest levels of phenols, condensed tannins and antioxidant activity were observed in light brown phenotypes followed by black and red seed coat color phenotypes. White phenotypes had the lowest levels of these compounds. Other traits for high polyphenols and antioxidant were a smooth seed coat, and mid-maturing plant, as opposed to rough see coat and early maturing plants. Only black and red phenotypes had detectable anthocyanins. Quercetin derivatives were the most abundant flavonols in all phenotypes. In General, a phenotype with light brown (cream), red, or black, smooth seed coat and of medium maturity is likely to have the highest amount of bioactive compounds. This indicates genetic selection for health promoting cowpea is feasible.