Evaluation of the Physicochemical and Sensory Properties of Yam-Based Semolina Fortified with Orange-Fleshed Sweet Potato and Beetroot Flours

Abstract

The physicochemical and sensory properties of yam-based semolina fortified with orange-fleshed sweet potato and beetroot flours were evaluated. Yam, orange-fleshed sweet potato and beetroot were processed into flours using traditional methods. These flours were used to formulate semolina by blending them in the ratios of 100:0:0 (YB1), 80:10:0 (YB2), 70:20:10 (YB3) and 50:40:10 (YB4) yam-orange flesh sweet potato-beetroot respectively. The resulting products were subjected to sensory evaluation using 9-point Hedonic Scale while the functional and pasting properties as well as the proximate composition of the most accepted composite sample were determined using standard analytical methods. The sensory acceptability of the formulated semolina significantly (p < 0.05) decreased with increasing substitution of yam with orange-fleshed sweet potato and beetroot flours. Sample YB2 was the only sample that was slightly acceptable with an overall acceptability score of 5.18 while the rest of the composite samples were rated below average. The values recorded for functional properties of sample YB2 were 6.88 for pH, 0.668 g/cm3 for bulk density, 77.86 % for water absorption capacity and 1.08% for oil absorption capacity. The peak viscosity, trough viscosity, breakdown viscosity, final viscosity, setback viscosity, peak time and pasting temperature of the sample were 268.17 RVU, 205.83 RVU, 62.33 RVU, 338.92 RVU, 133.03 RVU, 6.45 min and 88.85 oC respectively. The result of the proximate composition of sample YB2 were 10.45 % for moisture, 3.32 % for ash, 2.67 % for crude fibre, 1.23 % for crude fat, 2.44 % for protein and 79.96 % for carbohydrates. Improvement on the sensory qualities through modification of the product is recommended.