Influence of fermentation and cowpea steaming on some quality characteristics of maize-cowpea blends

Abstract

Fermentation and cowpea steaming can be used to improve the protein quality and quantity of fermented maize dough. In the production of maize-cowpea blends, it is important that the quality characteristics are evaluated to determine their functionality in the products. A 5x4x2x2factorial experiment with cowpea level, fermentation time, cowpea steaming time and fermentation method as the variable was performed. The cowpeas were dehulled, steamed, dried at 65EC for 24 hours and milled into flours. Maize was soaked in water (18 hours), drained and milled into flour. The maize-cowpea blends were made into a 50% moisture dough, fermented for the specified periods, dried at 65EC and milled into flour. Samples were evaluated for pH, titratable acidity, water absorption and sugars. The pH and titratable acidity of the samples were affected by fermentation time, steaming time, and the levels of cowpeas in the blend. Cowpeas was the main source of glucose/galactose.Fermentation caused a reduction in stacchyose and glucose/galactose. The mixing of cowpea flour with fermented maize dough prior to drying (single component fermentation) gave similar effects on sugar concentrations as detected in the co-fermented samples (multi-component fermentation).Fermentation and steamed cowpea fortification can be used to produce high protein fermented cereal foods with reduced anti-nutritional factors.