Effect of wheat flour substitution with potato pulp on dough rheology, the quality of steamed bread and in vitro starch digestibility

Wheat flour substituted with potato pulp was applied in steamed bread to improve nutrient value and reduce the energy consumption and the cost. The dough rheology, starch–gluten network, the quality and in vitro starch digestibility of steamed bread containing 0%–50% potato pulp were investigated. The dough sample with 10% potato pulp content exhibited the optimal elastic and viscous modulus values. Scanning electron microscopy (SEM) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed that dough samples with potato pulp contents of more than 30% weakened starch–gluten interaction and exhibited discontinuous network structures. Steamed bread with 30%–50% potato pulp contents showed reduced specific volumes and increased hardness. The rapidly digestible starch contents and expected glycaemic indices of steamed bread enriched with potato pulp decreased from 46.98% to 31.40% and from 87.81% to 72.79%, respectively. In conclusion, wheat flour substituted with potato pulp can be used in the energy-efficient and cost-effective production of steamed bread with improved nutritional value.