Nutritional Quality and In vitro Protein Digestibility of Complementary Foods Formulated from Maize, Cowpea and Orange-Fleshed Sweet Potato Flours: A Preliminary Study

Abstract

Complementary foods were formulated from blends of maize, cowpea and orange fleshed sweet potatoes (OFSP). Five different blends of flour were formulated with the substitution with cowpea flour at 5-30%, and OFSP substitution at 5-20% while 100% maize flour was used as the control. The flour blends were heated and extruded using a cold extruder. The samples were thereafter analyzed for their proximate, mineral, and vitamin compositions, and % In vitro Protein Digestibility. The moisture, ash, fat, crude protein, crude fibre, carbohydrate and energy of the complementary fruits samples varied from 8.11-11.39%, 2.27-3.66%, 2.20-3.10%, 8.87-13.07%, 2.39-4.07%, 68.90-73.43% and 357.08-367.68 Kcal/100g, respectively. All the samples were within the standard RDA for infants and young children, except for fat which was less than 10% recommendation. The mineral contents of the complementary food samples ranged from 44.20 – 80.67mg/100g for calcium, 8.86 – 24.50 mg/100g iron, 127.23- 167.72 mg/100 g magnesium, 1.53 -3.17 mg/100g zinc, 31.75 – 63.75 mg/100g phosphorus and 26.86 – 39.98 mg/100g sodium. There were significantly increase (p < 0.05) in these minerals as the substitution with cowpea and OFSP flours increased. β -carotene and vitamin C content of the complementary food samples ranged from 10.90 – 31.00 mg/100g and 1.80 – 12.01 mg/100 g, respectively.  Increase in substitution with cowpea and OFSP led to an increase in β -carotene values. Vitamin content also increase significantly (P<0.05) with increase in proportion of cowpea and OFSP flours. % in vitro protein digestibility of the samples varied between 30.29 in MCOA (100% maize complementary food) to 48.77% in sample MCOF (50% maize: 30% cowpea: 20% OFSP). Protein digestibility of the complementary food samples also increased significantly with increase in substitution. Most of the nutrients were highest in the samples containing 20% an 10% OFSP and 30% cowpea and 20% OFSP, making these samples suitable for use as of complementary foods.