Effect of Addition of Dehulled Germinated and Nongerminated Faba bean and Cowpea Flours to Wheat Flour and its Effect on Bread Quality

Abstract

This study was carried out to test the effect of adding faba bean and cowpea flours to wheat flour on the quality of dough and bread. Wheat flour in standard bread formulation was replaced with dehulled faba bean and cowpea flours before and after germination at levels of 5, 10 and 15% (wt/wt). Samples of wheat, cowpea and faba bean were analyzed for ash, moisture, fat and protein. Moisture content was 13.68, 7.33, and 9.26%, ash content was 0.55, 2.81 and 3.03%, protein content was 11.47, 28.03 and 23.01% and the fat content was 2.35, 1.53 and 1.57%, for wheat, faba bean and cowpea flours, respectively. Amino acids profile was studied for wheat flour, faba bean and cowpea (before and after germination), germination has lowered the levels of all amino acids except glutamtic acid which increased in both faba bean and cowpea. Also, serine and aspartic acids have been increased in faba bean after germination. In cowpea lysine has increased. Wheat flour and composite flours were tested for gluten quality and quantity. while falling number, farinograph and extensograph characteristics were determined. Specific volume and sensory evaluation tests were conducted on bread made from composite flours. Falling number showed a significant (P≤0.05) decrease with increase of germinated cowpea and faba bean flours from 489 sec. in control sample to 243 sec. in 15% germinated faba bean flour and 206 sec. with 15% germinated cowpea flour. Generally, addition of cowpea and faba bean flours to wheat flour increased water absorption, development time and degree of softening, 57 while the stability of dough was decreased. Adding faba bean and cowpea to wheat flour decreased the energy, extensibility and maximum resistance of wheat flour and increased its resistance to extension and ratio number. Bread with 5% germinated faba bean or cowpea flours gave the highest specific volume (3.70 and 3.73 g/100 g, respectively) of bread loaf and gained the highest score of general acceptance. 58