Optimising viscosity and energy density of maize porridges for child weaning in developing countries

Abstract

The energy density of traditional starch-based weaning foods used in many developing countries is a major constraint in ensuring adequate energy and nutrient intake for infants and young children. Viscosity and energy density of weaning foods are inextricably linked but studies investigating the two and their interrelationships are scarce. In this study, the factors influencing the viscosity and energy density of weaning maize porridges were investigated in a 2⁸ fractional factorial experiment. The factors investigated included: flour particle size (coarse or fine), concentration (6 or 8%), cooking time (5 or 10 min), temperature at time of measurement (30 or 40°C), shear speed (256 or 512 rpm), shear time (20 or 60 min) and addition of energy-dense foods; groundnut paste replacing 25% of the maize flour (w/w) and/or pasteurised cow's milk replacing 10% of the water (v/v). The viscosity of the maize porridges was significantly increased by increased concentration and cooking time (P ≤ 0.0001) and use of flour of fine particle size (P = 0.002). Increased shear speed and addition of groundnut paste and/or pasteurised cow's milk significantly (P ≤ 0.0001) reduced the viscosity of the porridges. Overall, milk decreased the viscosity of the porridges by 26.0%, groundnut by 56.1% and milk plus groundnut by 64.9%. The energy density of the porridges was significantly (P<0.0001) increased by increasing concentration and addition of groundnut and/or milk. Averaging the two concentrations, the energy density of the porridges was increased by 11.5%, 25.0%, and 36.4% by the addition of groundnut, milk and groundnut plus milk, respectively. These results indicate that the viscosity of weaning maize porridges can be reduced and the energy density increased by variation of some physical parameters and supplementation with energy-rich foods. The results have important implications for the amelioration of protein-energy malnutrition in children in developing countries.