Effect of fermented/germinated cowpea flour addition on the rheological and baking properties of wheat flour

Abstract

There is a growing interest in fortifying wheat flour with high lysine material, such as cowpea flour, to improve the essential amino acid balance of baked food products. The use of cowpeas as a food source has not been utilised fully, especially in developed countries. In this research, wheat flour in a standard bread formulation was partially replaced with cowpea flour, germinated cowpea flour and fermented cowpea flour at levels of 5%, 10%, 15% and 20% (wt/wt). Composite flours were analysed for ash, protein, gluten contents and α-amylase activity as well as colour, farinograph and extensograph characteristics. Bread baked from composite flours was analysed for loaf volume and weight, texture, crumb-grain structure and colour. Increasing levels of cowpea flour in the blends resulted in changed flour characteristics such as ash and protein contents and colour. It also changed farinograph and extensograph characteristics, mainly by increased water absorption. Incorporation of cowpea flour exerted a certain volume depressing effect on the bread and gave a compact structure at higher substitution levels. Overall acceptable results were obtained based on characteristics of control bread.