EFFECT OF REFINING AND SUPPLEMENTATION ON THE VISCOSITY AND ENERGY DENSITY OF WEANING MAIZE PORRIDGES

The study was undertaken to establish the extent to which use of refin ed maize flour in weaning porridges affects the viscosity and the ener gy density of the resulting porridges. Maize porridges from both refin ed and whole flours were made using modified traditional methods and t he viscosity of the porridges was measured using a rotational viscomet er. Other factors that might influence the viscosity outcome of the po rridges such as flour concentration, supplementation with energy-rich foods, cooking time, temperature at the time of measurement simulating feeding temperature and shear speed were included at three levels per factor (low, medium and high) in a Central Composite Design. Overall, refined flour porridges had significantly (P less than or equal to 0. 0001) higher viscosity than whole flour porridges. Increasing concentr ation and cooking time significantly (P less than or equal to 0.0001, P = 0.0003, respectively) increased the viscosity of the maize porridg es while addition of groundnut, addition of cow's milk and increased s hear speed had the desired effect of reducing the viscosity of the por ridges (P less than or equal to 0.0001, P = 0.001, P = 0.0002, respect ively). The energy density of the porridges as determined from the pro ximate values of the raw ingredients showed that refined flour porridg es had an average of 4% less energy density than the whole flour porri dges at equivalent influencing factors. These results show that refine d flour produces porridges of significantly high viscosity (stiff cons istence), making it practically impossible for the mothers to increase the energy density of the porridges through addition of more flour. M aize flour for use in weaning porridges should therefore be only moder ately refined to avoid the high viscosity/low energy density problems associated with over-refined flours.