Modelling of Proximate Composition of Amaranth, Sorghum, Pumpkin and Sunflower Flour Blends using Response Surface Methodology

Blends of cereals and legumes have gained attention especially in complementary nutrition. Optimization of the production of composite flour from defatted amaranth, sorghum, defatted pumpkin and defatted sunflower flour using D-optimal mixture design of Design Expert software with the levels for amaranth (40-60 %), sorghum (10-30 %), pumpkin (20-40 %), and sunflower flour (3-10 %), respectively was carried out. The responses were proximate composition. Run 5 and 14 recorded the highest crude protein (4.08 %) and total ash content (5.71 %) while run 7 and 10 had the highest fibre content (4.08 %.), respectively. The model terms were significant (p≤0.05) for the proximate composition of the blends with R2 values of 0.93, 0.92, 0.96, 0.90, 0.91, and 0.90 respectively for moisture, protein, fat, ash, fibre, and carbohydrate. The optimal blend from the numerical optimization through the desirability function approach were 42.46% amaranth, 10.00% sorghum, 40.00% pumpkin, and 7.54%. In conclusion, composite flour from amaranth, sorghum, pumpkin and sunflower flour have acceptable proximate composition in terms of nutritional quality necessary for the production of nutrient-dense food products capable of addressing issues of malnutrition.