Bárbara Amorim Silva

(1) Background: Starch-based breads can closely mimic wheat bread in texture and appearance; however, their nutritional value must be improved while maintaining their inherent bread-like characteristics. The objective of this study was to incorporate whole-grain pearl millet flour (PMF) into a starch-based bread formulation to enhance its dietary fiber and protein content. (2) Methods: The PMF was obtained using a combination of laboratory rollers and hammer mills, as well as appropriate sieves to obtain a particle size ≤ 250 µm. The incorporation of PMF affected the properties of the base flour (BF), dough, and gluten-free bread (GFB). (3) Results: In the BF, setback viscosity was significantly reduced from 6379 to 1354 mPa·s. Similarly, in the freshly kneaded dough, both the elastic and viscous moduli decreased, from 168.3 to 17.8 kPa and from 36.3 to 4.3 kPa, respectively. During fermentation, dough-specific volume increased from 0.76 to 1.73 cm³/g. In the GFB, the moisture content decreased from 47.9 to 42.2%, bread specific volume varied from 2.13 to 2.68 cm³/g, and crumb hardness increased from 12.8 to 25.3 N. PMF incorporation segmented bread consumers into two preference-based clusters, characterized by lower (1) and higher (2) PMF levels. (4) Conclusions: Incorporating 30% PMF increased the fiber and protein contents of the starch-based bread by 4.9% and 2.2%, respectively, without compromising specific volume (2.56 g/cm³) or overall acceptance, which remained comparable to that of a commercial gluten-free bread (7.30 and 6.32 for clusters (1) and (2), respectively).

The aim of this work was to evaluate the dough rheological properties along with the textural, physical, colorimetric, structural, total phenolics, anthocyanins and antioxidant properties of breads composed of wheat and Peruvian INIA 601 purple corn flour at three levels of substitution (5%, 15%, and 25%). Paste profiles describe the gelatinization, swelling, and decomposition phenomena of starch-based systems. These profiles were strongly affected at 15% and 25% replacement levels of purple corn INIA 601, attributed to the presence of phenolic compounds, which retarded starch gelatinization by increasing energy demands to reach paste temperature. Farinographic analysis evaluates key quality properties of the dough and provides insight into its rheological behaviour. In them, 5% purple corn flour substitution had a gluten-enhancing effect that increased the dough consistency, given the reducing capacity of the polyphenols that caused the aggregation of gluten proteins. But at levels of 15% and 25% it affected dough stability and tolerance properties (p < .05). In the rheometry properties, the addition of purple corn increased the elastic (G′) and viscous (G″) modulus. However, the hardness as the most important textural parameter of breadcrumbs was not affected up to 15% purple corn incorporation levels (p < .05). Multivariate, heatmap, and correlation analyses identify patterns and relationships, offering insights into variable interactions. Correlation studies showed interesting associations (0.90 > r > 0.99) between the bread responses. In conclusion, the incorporation of INIA 601 purple corn can generate anthocyanin-rich pigmented breads with higher concentration of phenolic compounds, anthocyanins and antioxidant capacity, which showed physical characteristics like wheat without drastically affecting crumb cell structure and bread volume.