Study of suitability of cassava and cowpea flours for making bread

Abstract

This study was done in Tanzania and Mozambique to assess the effect of cassava and cowpea flours singly and in combination in bread making and the degree of acceptability of the bread. Five to 20% cassava and 5 to 30% cowpea were used as wheat flour diluents. As the amount of diluents increased, the loaf volume decreased. The bread size ranged from 560 ml for 30% cowpea bread to 890 ml for 100% wheat bread and from 420 to 620 ml for the pan bread, the highest value being for whole wheat bread and the lowest for 30% cowpea composite bread. The bread weight increased for cowpea composite bread and the combination cassava-cowpea composite breads, ranging from 214 to 250 g for wheat bread and from 260 to 290g for pan bread, the highest values being for 30% cowpea bread and the lowest for 5% cassava composite bread. The specific loaf volumes were 2.39 to 4.07 ml/g for wheat breads and 1.45 to 2.31 ml/g for the pan type breads. Baking losses decreased as the amount of cowpea increased. However, cassava inclusion showed no decrease in baking losses. Cassava composite breads decreased protein content but increased mineral content. Cowpea bread had increased nutrients. The 30% cowpea bread was least accepted as also reflected in the lowest buying preference. For the pan bread, the lowest value was for the combined 10% cassava-5% cowpea bread and the highest value for 10% cowpea bread. This study concluded that up to 15% substitution, the formulation results were promising. Beyond 15% there were changes in organoleptic attributes and poor gas retention reduced loaf volume. Incorporation of cassava or cowpea flour gave a compact structure at higher substitution levels. Increasing levels of cowpea flour in the blends resulted in increased ash and protein and colour changes. The nutrient gains when cowpea is used in composite flour formulation need exploitation.