Effect of Partial Substitution of Wheat Flour with Sweet Potato Flour on the Chemical Properties, Bioactive Compounds and Digestibility of Bread Produced in Faranah

The reliance on imported wheat flour and the need to improve the nutritional quality of bakery products justify the exploration of local raw materials as alternative ingredients. This study evaluated the effect of partial substitution of wheat flour with sweet potato flour on the chemical characteristics, bioactive compounds, and digestibility of bread produced in Faranah. Bread formulations were prepared by replacing 10 to 50% of wheat flour with sweet potato flour obtained from four varieties. Chemical parameters (moisture, dry matter, ash, protein, starch, and fiber contents), bioactive compounds (carotene and total polyphenols), and digestibility were determined. Results showed a significant increase in ash content (3.66 ± 1.26%) and dietary fiber (12.87 ± 0.06%) in enriched breads. Carotene content increased from 0.58 ± 0.04 g/kg in the control to 2.72 ± 0.16 g/kg, while total polyphenol content reached 952.58 ± 10.62 mg GAE/100 g compared to 307.03 ± 2.70 mg GAE/100 g in the control. Digestibility decreased with increasing substitution levels, from 93.26 ± 4.16% in the control. Principal component analysis revealed a positive correlation between carotene and polyphenols and a negative association with digestibility. Substitution levels of 30–40% offer the best compromise between nutritional enrichment and acceptable digestibility.