Effect of Cassava Flour Processing Methods and Substitution Level on Proximate Composition, Sensory Characteristics and Overall Acceptability of Bread Made from Wheat- Cassava Flour Blends
The consumption of bread is globally increasing. However, due to increased costs associated with production of bread from 100% wheat flour especially in developing countries, other cereal based flours are now being blended with wheat flour to produce bread. This study was carried out to assess the effect of using two differently processed cassava flour (fermented and unfermented) and substitution level on proximate composition, sensory characteristics and overall acceptability of bread made from wheat-cassava flour blends. Bread was made using wheat flour incorporated in fermented and unfermented cassava flour at the ratios of 100:0, 90:10 and 80:20 for wheat: cassava flour, respectively and baked using a Morphy Richards (serial number 20076019) bread maker. The results showed that both the cassava flour and cassava flour substitution levels significantly affected (p<0.05) proximate composition, sensory characteristics and overall acceptability of the bread. Regardless of flour type, increased cassava flour substitution progressively decreased the crude protein and fat contents while the ash content was increased. The trend in significant differences as a reflection of the effect of cassava flour type and substitution level for the bread sensory characteristics was not consistent. Bread made from the 100% wheat flour was not significantly different from breads made from the following cassava flour type and substitution levels: 10% fermented cassava flour, 10% unfermented flour and 20% unfermented cassava flour in colour, texture, aroma and taste. Significant differences were observed between bread made from the 100% wheat flour and breads from the following cassava type and substitution levels: 20% fermented cassava flour, 10% and 20% unfermented cassava flour in colour, texture, aroma and taste. Overall acceptability and index to volume were both significantly affected by the cassava flour type and substitution levels. In conclusion, cassava flour substitution levels in wheat-cassava flour blends for bread making should not exceed 10% regardless of how the cassava flour has been processed to ensure bread with improved proximate composition and acceptable sensory attributes.
Keywords: bread, acceptability, proximate, sensory, cassava