Variation in contents of crude protein and mineral elements in 32 cowpea (Vigna unguiculata (L.) Walp) accessions in Ghana

English

Thirty-two cowpea accessions were studied for variation in contents of protein and mineral nutrients (calcium, magnesium, potassium and sodium). Cowpea flour from 40 wholesome dried seeds of each accession was used for the analysis. The wet oxidation method was used to determine the content of mineral nutrients. Nitrogen content was determined by the Kjeldahl procedure. Protein content ranged from 16.35 to 27.27 per cent. Sodium content ranged from 90.53 to 91.30 ppm, and potassium content from 30.33 to 71.30 ppm. Similarly, values for magnesium and calcium ranged from 146.73 to 968.20 ppm and from 43.33 to 171.20 ppm, respectively. Percent crude protein correlated significantly positively with sodium and negatively with calcium. Magnesium was correlated significantly with potassium. Black seeds generally recorded the highest percent crude protein on the average, while cream seeds had the highest magnesium and calcium contents, respectively.

Asante, I. K.; Adu-Dapaah, H.; Addison, P.