Technological Aspects of Preparing Porridges Made from Local Crops in Mozambique

Abstract: Child malnutrition is one of the major health problems in many developing countries and involves many sectors such as health, agriculture and research. Malnutrition in infants usually develops during the introduction of complementary foods, due to a deficit of nutrients, low energy density and the poor bioavailability of vitamins and minerals leading, in turn, to an increase in the risk of disease and infant mortality. These complementary foods are usually prepared from starchy plants, the flour being heated with water causing swelling, resulting in a viscous porridge that is not suitable for consumption by small children. To circumvent this problem, it is common practice to dilute the porridge with water, which further reduces its nutritional value. Meat is often unaffordable for most of the population in the developing countries, while starchy crops are readily available. The aim of this study was, therefore, to investigate the use of locally available crops to produce complementary porridges with a palatable consistency, while maintaining the nutritional quality and energy density. Flours were produced from various crops: orange-fleshed sweet potato, cowpea, maize, sorghum and soybean. Three methods of measuring the swelling were investigated (centrifugation, gravity sedimentation and least gelation concentration), and the consistency of the porridges made from each flour was measured with the back-extrusion method. It was not possible to predict the consistency of the porridges based on the results of the swelling measurements, but it was possible to estimate the flour concentration that would give porridge with an acceptable consistency preferably using the gravity sedimentation method. Based on the results obtained for the consistency and assuming that the volume fraction contributions from different flours were additive, all possible two-flour combinations were investigated, all mixes gave a porridge with low consistency or in the predicted range. Fresh orange-fleshed sweet potato and cassava flour were used to develop a new product similar to garri, by roasting. The retention of β-carotene, the consistency, energy density and the consumer acceptance were evaluated. The higher retention of β-carotene (88%), overall preference (above 60%) and a significant reduction in viscosity made this product a promising source of precursor of vitamin A, while having a high energy density. Linear programming was used in an attempt to formulate a nutritious and affordable complementary food for children aged 1-8 years, using locally available crops. It was not possible to formulate a food with an acceptable nutritional value and consistency, using locally available crops that would be affordable for most rural residents of Mozambique. However, if the cost of supplemental micronutrients such as zinc and calcium can be reduced, the cost of this food could be reduced by more than 70%.