Rheological and pasting properties of composite flour from wheat, sorghum and finger millet

Abstract:

Leading cereal scientists have long argued that composite flours can address both nutritional deficiency and wheat-import dependence in East African countries. This research characterised the rheological and pasting behaviour of composite flours blending wheat with sorghum and finger millet at five ratios 100:0:0 (control), 80:10:10, 70:20:10, 60:25:15, and 50:30:20 to assess their suitability for flatbread and biscuit production. Farinograph, extensograph, and Rapid Visco Analyser (RVA) tests were conducted at the Rift Valley College of Food Technology, Hawassa, SNNPR, Ethiopia during 2023. Water absorption rose from 62.4% (wheat control) to 68.7% (50:30:20 blend) as non-wheat flour content increased. Dough development time shortened and stability decreased with higher millet and sorghum proportions, indicating weaker gluten networks. Peak viscosity dropped from 2,840 cP in wheat to 1,980 cP in the 60:25:15 blend and 1,580 cP in the 50:30:20 blend. Setback viscosity an indicator of staling tendency was lowest in the 70:20:10 blend (840 cP versus 1,290 cP for wheat). The 70:20:10 ratio offered the best compromise: acceptable dough handling, reduced staling potential, and a 34% increase in dietary fibre compared to refined wheat flour.