ABSTRACT

The study evaluated the effects of incorporating flours from a local, and select improved cassava varieties in bread formulation. Tubers of five new, improved cassava varieties, UMUCAS 36, UMUCAS 37 and UMUCAS 38, NR 87184 and TMS 0593 developed by the National Root Crops Research Institute, Umudike were obtained from the research institute and local variety, Nwany oji was obtained from the local farmers, and processed into high quality cassava flour. The flours were used in producing 10 – 20% wheat-cassava bread. The flours were analysed for chemical composition and functional properties. The bread were evaluated for proximate composition and physical and sensory properties. The cassava flours had 8.19 – 11.42% moisture, 0.51 – 1.07% protein, 1.63 – 2.84% crude fibre, 1.10 – 2.63% ash, 0.91 – 1.06% fat and 84.11 – 85.09% carbohydrate. The wheat flour had 9.96% protein, 1.56% lipid 1.04% ash and 0.60% crude fibre. The HCN content of the cassava flours was 2.87 – 6.07 mg/kg. The functional properties of the flours were: bulk density 0.76 – 0.96 g/ml, water absorption capacity 1.12 – 1.46 g/g sample, oil absorption capacity 1.42 – 1.60 g/g sample, foam capacity 12.89 – 16.70%, foam stability 2.04 – 3.03%, emulsion capacity 41.02 – 44.40%, swelling capacity 16.12 – 20.43%, gelatinization temperature 58.82 – 65.02 °C and gelatinization time 1.49 – 2.07 min. The bread had 74.70 – 84.92% dry matter, 15.08 – 25.37% moisture, 6.61 – 12.01% protein, 1.26 – 1.91% crude fibre, 1.02 – 2.87% ash, 1.26 – 2.66% fat and 61.28 – 68.16% carbohydrate. The HCN content of the bread was 0.65 mg/kg – 2.58 mg/kg, increasing as the cassava flour portion increased. The physical properties of the bread were 265.50 g to 375.00 g loaf weight, 693.0 – 1445.0ml loaf volume and 2.61 – 3.76 ml/g for specific volume. Generally, there was in every variety an increase in loaf weight but decrease in loaf and specific volumes with increase in the percentage of cassava flour in the composition. The NR 87184 performed best among the improved cassava varieties. The sensory scores, 6.45 – 8.05 (colour), 5.75 – 7.95 (aroma), 5.90 – 8.05 (taste), 6.55 – 8.05 (crust appearance), 6.65 – 8.05 (crumb appearance) and 5.65 – 7.95 (general acceptability), indicated the samples received a minimum of moderate liking by the consumers. Over all, these cassava varieties looked promising for use in bread formulation. The choice of variety would much depend on intended quality goals. However, it may be the necessary to use appropriate improvers to boost the physical properties of the composite breads. This could encourage the adoption of the wheat-cassava bread policy.