Functional and pasting properties of wheat / plantain flours enriched with bambara groundnut protein concentrate

Abstract

Composite flour was prepared from wheat/plantain flours (0-40%) enriched with bambara groundnut protein concentrate (0-30%) and using 100% wheat flour as control. Functional and pasting properties of the composite flour were evaluated. The bulk density of the flour blends ranged from 0.34g/ml (100% wheat flour) to 0.47g/ml, (95% plantain flour and 5% protein concentrate) suggesting that plantain flour is heavier than other substituted samples. Oil and water absorption capacities showed that 95% plantain flour had the least values of 69.0% and 71.3%, respectively and increased significantly with increase in the levels of bambara groundnut protein concentrate. Foam capacity increased with increase in bambara groundnut protein concentrate added, however, foam unstability was significantly higher (65.1%) in sample with (95%) plantain flour and 5% bambara groundnut protein concentrate. Emulsion capacity increased significantly (P ≥ 0.05) from 32.4% to 64.1% and emulsion stability after 20h ranged from 26.8% to 48.7% showing a significant (P ≥ 0.05) increase with the increase in protein concentrate. Minimum nitrogen solubility of 40.0% and 40.4% were observed in flour blends with 100% wheat flour and 60% wheat flour, 25% plantain flour and 15% bambara groundnut protein concentrates, respectively while the maximum nitrogen solubility of 85% occurred in sample C at pH 12. A peak viscosity of 248.12 RVU which was significantly (P ≥ 0.05) different from other flour blends was observed in sample with 100% wheat flour (sample A) while the least peak viscosity of 219.63 RVU was recorded for sample with 40% wheat flour, 35% plantain flour and 25% protein concentrate (sample F). A hold period (Trough viscosity) ranged from 178.44 RVU (sample F) to 205.81 RUV (sample A), peak time of flour blends increased from 4.7min (Sample A) to 6.7min (sample F) which increased as the level of plantain flour and protein concentrate also increased. Pasting temperature also increased in similar pattern, ranging from 66.9 o C to