Abstract:

This study investigated the nutritional composition of modified and unmodified resistant starches of African yam bean (AYB) and pearl millet (PM), alongside the sensory attributes of pearl millet bread supplemented with varying proportions of AYB flour. Proximate analysis revealed significant compositional shifts following modification. In AYB, modification reduced moisture (6.10% vs. 10.20%), fat (0.90% vs. 9.50%), crude fiber (0.20% vs. 1.90%), protein (8.00% vs. 21.40%), and ash (1.20% vs. 2.30%), while markedly increasing carbohydrate content (83.60% vs. 54.80%). Similar but less drastic trends were observed in PM, where modification lowered moisture (6.33% vs. 8.50%), fat (1.33% vs. 1.67%), crude fiber (2.83% vs. 3.50%), protein (8.75% vs. 13.12%), and ash (1.17% vs. 2.50%), with carbohydrates increasing to 63.52% from 57.83%. These results suggest that while modification enhances carbohydrate enrichment and potential industrial applications (e.g., bioethanol, starch-based products), it compromises nutritional quality by reducing proteins, minerals, and dietary fiber. Sensory evaluation of pearl millet bread showed that the control bread (100% PM) had superior acceptability across color, aroma, taste, and overall preference. Supplementation with low levels of AYB (5–10%) produced acceptable breads with improved texture and moderate consumer approval. However, higher inclusion levels (≥15%) negatively impacted sensory properties, with bitterness, dense texture, and undesirable aftertaste lowering overall acceptability. The optimal formulation was achieved at 5–10% AYB substitution, balancing improved protein and fiber contributions with sensory acceptability. In conclusion, modification of resistant starches in AYB and PM alters their proximate composition toward carbohydrate dominance but at the cost of protein and mineral losses. For food applications, moderate AYB incorporation into pearl millet bread (≤10%) is recommended to enhance nutritional quality without compromising consumer preference, while higher substitution levels or extensive modifications may be more suitable for industrial rather than direct dietary use.