Effect of Cowpea Enrichment on Some Quality Parameters of Maize: Cowpea Flour Blends

The objective of this study was to examine the complementary effect of cowpea on some quality attributes of maize flour. Production of nutritious low cost complementary foods is a panacea to malnutrition in developing countries. Wheat is a popular cereal grain that has been used for the production of many snacks, such as chin-chin, biscuit, pie, bread and other pastry products but the tropical climate of many developing countries does not encourage commercial wheat cultivation, leading to reliance on wheat importation. Dried yellow maize (Zea mays), cowpea (Vigna unguiculata) and other ingredients (onion, fresh pepper, palm oil) used for this research were sourced from Obada market in Emure-ile, Owo L.G.A of Ondo State, Nigeria. Flour blends were produced in the following ratios of maize: cowpea; 90: 10, 80: 20, 70: 30 and 100% maize as control. Physicochemical (proximate, mineral and functional properties) and microbiological analyses were carried out on the flour blends The proximate result showed that the protein content ranged from 8.85 to 10.52%, total ash, 1.55 to 1.93%; fat content, 10.50 to 11.96%; moisture content, 5.05 to 5.77% and fibre content, 9.88 to 14.43%. The blend with a 30% substitution of cowpeas produced the highest value. It was found that substituting cowpeas had no impact on the fat content. When cowpeas were substituted for other ingredients in the blends, the mineral analysis revealed that the contents of potassium, sodium, zinc, and iron increased, with 30% cowpea substitution having the highest values. While calcium was not detected in 100% maize, Calcium contents in the blends were 3.34, 3.36, 3.39 mg/kg for 10%, 20% and 30% cowpea substitution respectively;. Functional properties evaluated showed that bulk density ranged from 0.72 to 0.81g/ml, swelling index, 0.66 to 1.03 ml/g, least gelation, 2.10 to 6.11%, foaming, 7.67 to 15.36%, water absorption, 2.41 to 3.23%, oil absorption 1.24 to 1.45%, emulsion capacity, 8.76 to 37.15% and emulsion stability 7.43 to 14.13%. Microbiological evaluation for the flour blends showed that total viable count ranged from 3.80 to 4.7 x 103 Cfu/ml, while yeast and mould count ranged from 2.2 to 3.17 x 103 Sfu/ml for blends. The overall result showed that 30% cowpea substitution is the most adequate percentage to produce an acceptable and nutritious flour blend from maize and cowpea which can be useful for pastries and confectioneries. Cowpea enrichment did not significantly change the microbiological characteristics. In conclusion, cowpea can be combined with maize to create a composite flour that is high in nutrients and has improved functional qualities.