Effect of Defatted Groundnut, Banana and Maize Flour Blend on the Nutritional and Bioactive Contents of Extruded Snack

Abstract

Selecting appropriate food materials, compositions and combinations is important for the development of healthy foods. This study determined the effect of enriching maize with defatted groundnut and banana flours on the nutritional and bioactive composition of the flours and extruded snack. Maize, defatted groundnut and banana flours were prepared and blended at a ratio of 65:30:5, respectively. The extruded snack was prepared at 125 °C barrel temperature, 32% feed moisture and 420 rpm screw speed. Proximate composition, mineral content and antioxidant properties of the flours, blend and extruded snack were determined using standard methods. Moisture, crude protein, fat, fibre, ash and carbohydrate contents ranged from 2.98–9.95, 3.47–56.82, 1.41–8.56, 1.01–4.77, 1.05–3.73 and 26.35–87.57%, respectively. Iron, zinc and potassium contents ranged from 2.40–6.37, 1.52–3.51 and 148.95–217.46 mg/100 g, respectively. Total antioxidant activity ranged from 36.44–64.49 GAE/100 g in the flours and from 34.20–48.64 GAE/100 g in the flour blend and snack. Total phenolic content ranged from 97.38–349.85 mg/100 g in the flours and from 67.24–102.60 mg/100 g in the snack and flour blend, respectively. Total flavonoid content ranged from 18.36–87.69 mg/100 g in the flours and from 21.19–38.58 mg/100 g in the flour blend and snack. Extrusion increased iron, zinc and potassium contents, while total antioxidant activity and flavonoid content increased and total phenolic content decreased. Enrichment of maize with defatted groundnut and banana flours produced an extruded snack with enhanced protein, fibre, mineral and antioxidant contents.