PHYSICOCHEMICAL PROPERTIES AND COOKING QUALITY OF 4 NEW CULTIVARS OF NIGERIAN COWPEA (VIGNA-UNGUICULATA L WALP)

Four new cowpea cultivars (IT81D-699, IT82E-18, IT84S-2246-4 and TVx 3236) were evaluated for their physicochemical properties and cooking quality. The four cultivars fell into two categories (rough and smooth) according to testa texture, and varied in seed dimensions and weights with IT81D-699 and IT84S-2246-4 having smaller seed volume than IT82E-18 and TVx 3236. Leached solids, swelling capacity and seed coat percentage were within a range of 0.33-0.94 g per 100 g, 77.0-123.5 g per 100 g and 5.6,-15.7% w/w of dry beans respectively. The total polyphenol content of the brown or cream-coloured beans were similar (1.53-1.96 mg g-1) but higher than the amount (1.03 mg g-1) found in the white bean. Cooking time varied between 29 and 37 min and was reduced by about 21% following a presoaking treatment in water for 12 h at room temperature (28-degrees-C). Cooking time was significantly positively correlated (P < 0.05) with seed weight (r = 0.82) and seed volume (r = 0.75). Water absorption was not related to cooking time, and was much lower for the cultivar with larger seeds. No significant difference in hardness was found between unsoaked beans cooked for 30 min and soaked beans cooked for 10 min, suggesting that cookability for all cultivars was improved through soaking.