Nutritional Values and Medicinal Health Aspects of Brown, Brown-Black and White Cowpea (Vigna unguiculata L. Walp.) Grown in Okene, Kogi State, Nigeria

Abstract

Cowpea (Vigna unguiculata) is an annual legume thought to have originated in Nigeria. Cowpea has high protein and carbohydrate content with a relatively low fat content and a complementary amino acid pattern to that of cereal grains make it an important nutritional staple food in the human diet. This study aims to determine the phytochemical, nutritional values and medicinal health aspects of brown, brown-black and white cowpea grown in Okene, Kogi State, Nigeria. Three colours of cowpea seeds are dried and ground in powder form. The crude powder was tested for alkaloids, anthraquinone, carbohydrates, cardiac glycosides, fat and oils, flavonoid, Saponins, steroidal ring, terpenoids and tannins. The proximate analysis of the samples was carried out for protein content, ash content, fat content, moisture content, crude fiber and carbohydrate after drying each sample at room temperature. Vitamins and mineral elements were determined by the dry ash extraction. The phytochemical components of secondary metabolites of the extracts from the obtained result, anthraquinone were absent in each of the three colour of the samples and tannins were not present in the white seed. The proximate composition of a nutritive value of each samples. The brown and brown-black seeds has higher value of percentages (%) crude protein, % ash content, % fat content, moisture content, % crude fibre, % carbohydrate of amounting to (57.84, 4.53, 11.60, 7.24, 3.40, 55.98) and (58.59, 4.45, 10.9, 7.06, 3.90, 54.60) while the white seed has (50.20, 3.52, 9.30, 8.56, 4.11, 59.50) has low % crude protein, % ash content and % fat content value compared to brown and brown-black seeds of cowpea. The vitamins components of brown, brown-black seeds and white seed of Cowpea where vitamin A, B, C, E (131, 232, 9, 7) in brown seed, (142, 221, 7, 9) in brown-black seed and (113, 209, 6, 5) in white seed. The Mineral element of brown, brown-black and white seeds of Cowpea where Na, K, Ca, Mg, Fe, Zn, P and Mn (49, 981, 651, 123, 54, 35, 620, 1.0) brown, (58, 789, 668, 98, 43, 38, 590, 2.0) brown-black and (63, 684, 723, 299, 10.11, 23, 843, 0.5) white seeds were detected but Cu and N non-detected in each. The brown and brown-black seeds of cowpea is richer in proximate, vitamins and mineral nutrients compared to white seed of cowpea. Therefore, adoption, utilization and consumption of cowpea grains as source of food will be a step forward towards combating the protein-calorie malnutrition and iron deficiency in this part of the world.