Deamidated Rice Protein as a Functional Fortificant in Wheat Flatbread

ABSTRACT Background and Objectives Wheat flatbread is a major dietary staple but has limited protein quality. This study evaluated native rice protein isolate (RPI) and rice protein isolate deamidated using a natural deep eutectic solvent (NADES) system (dRPI; 1%–5%, w/w) as clean‐label fortificants to improve the nutritional properties of whole‐wheat flatbread. Findings Fortification enhanced protein quality, increasing lysine from 0.270 g/100 g in the control to 0.368 g/100 g in flatbread fortified with 5% dRPI. Protein Digestibility‐Corrected Amino Acid Score (PDCAAS) increased from 41.8% to 47.1%, while the predicted glycemic index decreased by up to 16.8%. Fortified doughs remained processable, with arrival and departure times comparable to the control, moderate increases in dough development time (4.4 to 4.5–6.0 min), and dough stability remaining within a workable range across treatments (3.1–4.3 min). Although both variants showed acceptable sensory characteristics, dRPI‐fortified flatbreads achieved better acceptance than RPI‐fortified samples, which showed greater grittiness at higher inclusion levels. Conclusion Both fortificants improved nutritional quality, but dRPI maintained better functional and sensory performance, with 3% dRPI offering the best overall balance. Significance and Novelty NADES‐deamidated rice protein is a promising clean‐label fortificant for nutritionally improved wheat flatbread.