Potential of cowpeas-cereal blends as alternatives to corn-soy blend for children under five years

Abstract

Malnutrition is a burden among children below five years of age in Uganda due to inadequate intake of proteins and micronutrients. Children are often weaned onto adult foods such as matooke, potatoes, unfermented or non-germinated; maize, millet, cassava porridges. These foods are mashed and diluted resulting into being limited in protein and energy. This study therefore, aimed to modify starch in the cereals and enhance the nutrient content to obtain a desirable nutrient-dense and optimal viscosity of a complimentary porridge. Extrusion processing was used to produce instant porridge flour blends. Design Expert formulation software version 11.0.3.0 was used to estimate the optimum amounts of cowpea, millet, maize and sorghum flours in order to meet the target nutrient contents for protein (14%), fat (6%) and energy (380 kcal per 100 g) of cowpea–cereal blend. The World Food Program (WFP) corn soy blend plus was used as a reference. Flour blends were separately mixed with water to achieve moisture content levels of 14, 16 and 18% and fed into the extruder at a barrel temperature of 150 oC and varying screw speeds of 40, 45 and 50 Hz. The flours were then packed in polythene bags and stored at 4 °C until analysis was conducted. Feed moisture content of 17.17% and screw speed of 50 Hz were selected as optimal processing conditions for the processing of maize-cowpea blend. These processing conditions resulted in flour with fat content (0.73%), ash content (2.7%), protein content (13.2%), protein digestibility (56%), energy (259 kcal), final viscosity (105.6 CP), and pasting temperature (53.9 oC). In addition, a feed moisture content of 17.46% and a screw speed of 45 Hz were optimal conditions for the production of sorghum-cowpea blend. These processing conditions resulted in extrudates with fat content (0.68%), ash content (3.1%), protein content (10%), protein digestibility (73.1%), energy (242 kcal), final viscosity (75.8 CP), and pasting temperature (57.3 oC). On the other hand, feed moisture content of 18.0% and screw speed of 50 Hz resulted in extrudates with ash content (3.0%), protein content (12.6%), protein digestibility (84.4%), energy (252 kcal), final viscosity (70.6 CP), and pasting temperature (56.7 oC). The sensory testing of porridge showed that all cowpea-cereal composite made porridge acceptability scores above 5 suggesting they were all acceptable though the reference - corn soy blend plus had higher scores. Sensory evaluation scores showed that all cowpea-cereal composite porridges received acceptability scores above 5, indicating they were acceptable. However, corn-soy blends plus had higher scores than cereal-cow pea blends. The study showed that the use of locally available cereals and cowpeas at optimal processing conditions improves the nutrient content making it suitable for use as a weaning food in resource-poor communities.