Valorization of Potato, Cassava, and Yam Starch Extraction Residues in Wheat Bread: Effects on Dough Extensibility, Expansion, Crumb Structure, Texture, and Consumer Acceptance

Starch extraction generates solid residues that could be valorized as alternative ingredients in bakery products. This study evaluated potato, cassava, and yam starch extraction residue flours as partial substitutes for wheat flour in bread at 15, 25, and 35% replacement. Residue flours were characterized for proximate composition, particle size distribution, and physicochemical properties, and their incorporation was evaluated through dough extensibility, bread quality, and consumer acceptance. Potato residue flour exhibited water retention and swelling capacities of 74.12% and 22.49 mL/g, respectively, compared with 56.41% and 6.53 mL/g for cassava and 64.79% and 12.24 mL/g for yam. At 15% substitution, cassava-containing dough showed no significant difference in extensibility relative to the control (89.09 versus 85.34 mm), whereas potato and yam formulations showed reductions of approximately 12% and 21%, respectively. At 35% substitution, extensibility decreased by 30–43% across the formulations. Bread expansion decreased with all three residue flours. At 35% replacement, the crumb cell area fraction decreased by 81% and 66% in potato- and cassava-containing breads, respectively, whereas yam formulations showed no significant differences from the control throughout the substitution range. Potato substitution increased hardness by 168% and 121% at 25% and 35% replacement, respectively, whereas cassava formulations showed reductions of approximately 19–32% relative to the control. Moisture and water activity showed no significant changes. Favorable sensory ratings were observed for potato at 15%, cassava at 15–25%, and yam at 25–35% substitution. These findings identify opportunities for incorporating starch extraction residues into bread under a fixed-water formulation, with substitution levels selected according to the technological and sensory responses of each residue flour.