Influence of cassava genotype and composite flours' substitution level on rheological behaviour during bread-making

Given increasing dependence on imported wheat, studies have been carried out in Colombia regarding the use of composite wheat-cassava flour in bread-making. A project was carried out from 1986-1991 in which different cassava genotypes, harvest ages, substitution levels and bread acceptability were evaluated. However, these studies did not have any effect on the baking sector because a constant supply of high quality, high volume and reasonably-priced cassava flour was locking. Based on these studies, this work was aimed at determining the influence of three industrial cassava market genotypes (CMC-40, HMC-1, MCOL-1505), using four wheat-cassava flour composite substitution levels (0%, 5%, 10%, 15%) regarding the rheological and fermentative characteristics of dough in bread-making. Farinogram, alveogram, amylogram and falling number index analysis were analysed. Specific volume and acceptability of three types of bread (common, mold and hamburger) were evaluated. It was determined that composite flours had higher fiber and reduced sugar content than the wheat flour pattern, thereby increasing water absorption and available sugar content during fermentation. Dough development time for the composite flours was half the average required for wheat flour and the tolerance index was higher; its stability become reduced due to increased substitution levels and its firmness increased due to a rise in water absorption. Failing number values came within an acceptable range (250400 s). The specific volume of all bread having 5% and 10% substitution was higher than that for the pattern. The best general acceptability was assigned to common and mold type bread from all varieties and substitution levels.