Nutritional Composition of Three Varieties of Cowpea (Vigna unguiculata) Grown in Benue State, North Central Nigeria

Cowpea is a nitrogen-fixing legume of immense nutritional and agricultural significance in sub-Saharan Africa. Benue State, known as Nigeria's food basket, produces substantial quantities of cowpea for local consumption and trade. Despite this, varietal differences in nutritional composition among locally grown cowpea remain poorly documented. This study evaluated the proximate composition, mineral content, and anti-nutritional factor levels of three cowpea varieties cultivated in Gboko, Makurdi, and Otukpo Local Government Areas of Benue State: brown-eyed cowpea, white cowpea, and black-eyed cowpea. Seeds were harvested at full maturity and processed into flour using standard laboratory milling techniques. Proximate analysis followed Association of Official Analytical Chemists methods, mineral content was determined by atomic absorption spectrophotometry, and anti-nutritional factors including tannins, oxalates, and phytates were quantified colorimetrically. Results showed white cowpea had the highest crude protein content (26.4 percent), while black-eyed cowpea exhibited the lowest anti-nutritional factor levels, suggesting superior bioavailability. Brown-eyed cowpea showed intermediate values across all parameters. All varieties contained appreciable iron and zinc levels relevant to addressing deficiency in North Central communities. The study recommends prioritising white cowpea cultivation for protein enhancement programmes and black-eyed cowpea for households with anti-nutritional concerns. Keywords: cowpea, proximate composition, anti-nutritional factors, Benue State, legume.