Effect of blend levels on composite wheat doughs performance made from yam and cassava native starches and bread quality

The effects of refined wheat flour substitution with two native starches from yam tuber and cassava root, and two commercial products, a specialty starch, C*Actistar and a wheat bran flour, at 10%, 20%, 30%, 40% and 60% dry basis, on the rheological properties of dough and bread characteristics, have been examined. In general, during the mixing phase, the substitution of white wheat flour for starch or wheat bran flour had a tendency to modify the flour strength from strong to weak, depending on the nature of the added fraction and the level of substitution. Yam starch and wheat bran flour weakened dough strength to a lesser extent in comparison with cassava starch, and by far, the resistant starch, C*Actistar. In addition, differences in dough expansion appeared among the botanical origins of composite dough and the blend proportions, during the fermentation phase. White wheat flour substitution for yam starch up to 30% or cassava starch up to 20% led to kinetics expansions of resulted doughs close to that of the control, while those of doughs containing C*actistar starch or wheat bran flour were significantly slower than that of the control, whatever the level of substitution. The baking phase showed that yam starch enriched breads from 10% to 40% of substitution and cassava starch enriched breads from 10% to 30% of substitution gave as bulky loaves as the refined wheat bread. Beyond these concentrations, the resulting breads were less voluminous. Hedonic tests revealed that, 30% yam starch substitution and 20% added cassava starch led to composite breads which met consumer satisfaction on all attributes, as the control.