Proximate Composition and Functional Properties of Soybean and Cowpea Flour Blends for Food Fortification in Kwara State

Protein-energy malnutrition continues to be a public health challenge among children under five years of age in North Central Nigerian states, and the development of affordable, locally sourced food supplements from leguminous crops represents a practical intervention strategy. This study evaluated the proximate composition and functional properties of composite flours prepared from varying blends of soybean and cowpea, both of which are widely grown and consumed in Kwara State. Flours were prepared individually by cleaning, roasting, dehulling, and milling, and then blended at ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 representing soybean to cowpea proportions. Proximate analysis was carried out using AOAC methods, and functional properties including water absorption capacity, oil absorption capacity, foaming capacity and stability, emulsification capacity, gelation temperature, and swelling power were determined. Protein content ranged from 22.8 percent in the all-cowpea blend to 38.4 percent in the all-soybean blend, with intermediate blends showing proportionate values. Fat content was highest in soybean flour at 18.7 percent. Carbohydrate content was inversely related to protein content across blends. Water absorption capacity improved with increasing cowpea proportion. The 75:25 soybean-to-cowpea blend exhibited the most balanced combination of high protein content, acceptable functional properties, and digestibility. These results suggest that this blend ratio is suitable for the development of high-protein infant weaning foods and nutritional supplements in Kwara State.

Keywords: soybean, cowpea, composite flour, proximate composition, functional properties