Quality Evaluation of Yam (Dioscorea rotundata) and carrot (Daucus carota L.) Flour Blends for Production of Stiff Dough and Biscuits

Abstract

This study evaluates the quality of yam and carrot flour blends for the production of stiff dough and biscuits. Flour samples were prepared from yam tubers and carrot flours .The carrot flour was used to substitute 5, 10, 15, and 20 of the yam flour on the stiff dough. Biscuits were prepared from various blends of wheat flour, carrot flour and yam flours. The proximate composition, functional properties, vitamin, minerals and sensory attribute of the flour blends were carried out using appropriate standard methods for the analysis. The sensory properties of the stiff dough and biscuits were determined. The proximate composition of the flour blends were significantly (P< 0.05) different for the moisture (7.52.-6.89%), ash (2.00-2.36%), protein (4.90-4.55%), fat (1.41-1.25%) and carbohydrate (82.09-77.73%). The water absorption (2.53 – 4.10%) and least gelation concentration( 6.43-12.03%) of the blends increased while the bulk density  (0.65-0.53 g/ml), dispersibility (1.49 -2.50%), swelling capacity( 2.59 -3.83%) and foaming capacity (26.73-6.44 g/ml).The blends were rich in iron( 8.43-19.22 mg/100g), zinc (7.43-18.11 mg/100g), magnesium (94.54-170.49 mg/100g) and phosphorus (30.63-84.01 mg/100g). The blends were rich in pro-vitamin A (5.51-17.42). Vitamin B1 (0.43-0.84) and vitamin C (4.81-17.81 mg/100g). The sensory scores recorded on the flour blends for appearances (7.10- 8.50), texture (7.40 -8.10), taste (7.10 -7.85), aroma (6.70 -7.60) and acceptability (6.35-7.70) decreased with increasing level of carrot flour in the blends. The biscuits containing  75% wheat flour, 20% yam flour and 5% carrot flour was the most preferred.