Drying effect on functional properties of two plantain and cowpea varieties and suitability of their flour blends in extruded snacks was determined. The functional and rheological behaviors of (plantain : cowpea): 90:10, 80:20, 70:30, 60:40 and 50:50 blends were evaluated. The extrusion product melt temperatures were set to 90C for half-products, and 140C for fully expanded snack products. The differences in rheological properties depended on plantain and cowpea varieties. The peak viscosity for plantain flour decreased from 595.5 to 281.5 BU when blended with cowpea flour (75:25%); cowpea peak viscosities were 6 BU (Nhyira means blessings) and 13 BU (Asetenapa means good living). Paste value decreased as amount of cowpea flour blended with plantain flour increased. Pasting properties of the extrusion blends were significantly different (P < 0.05) depending on the blend ratios. The level of cowpea added affected the paste, hardness properties and the expansion height of the extruded products.
The purpose of this work was to develop a long-term storage of indigenous local raw materials, to reduce postharvest losses and add economic value. The cowpea was used as a protein source to fortify the high carbohydrate plantains, with the aim of developing local snack industries in Ghana and other sub-Saharan Africa countries. Perishable raw materials will be processed into shelf-stable flours and extruded snacks, enhancing food security.