Optimization of Nutritional and Pasting Properties of Rice-Sweet Potato Based Composite Flour for Biscuit Production

Rice-sweet potato based biscuit was produced from optimization of the composite flour. The composite flour consisted rice, sweet potato and soybean flours with carboxyl methylcellulose as binder. Experimental design and statistical analysis were carried out using optimal mixture design of response surface methodology. The proximate compositions were optimized while the pasting characteristics and amino acid profile of the optimum blends were evaluated. The sensory evaluation and mechanical properties of the biscuit produced were also determined. The result showed that 15 of the 16 samples had protein content above 10 g/100g. This value is considerable if compared with 100% wheat flour. Samples 6 (85.694% rice flour, 11.806% sweet potato and 2.5% CMC) and 7 (95% rice flour, 2.5% sweet potato flour and 6.765% CMC), specifically, had high levels of ash, fibre and protein contents. In addition, all the samples had carbohydrate content above 70 g/100g. The result of the pasting characteristics showed that the composite flour had good flour quality. The addition of the binder (carboxyl methyl cellulose) enhanced the pasting properties. In addition, the amino acid profile showed that the composite flour had all the nine essential amino acids. The biscuit produced had good mechanical and sensory properties