Functional and physicochemical properties of fava bean protein concentrates obtained from isoelectric pH precipitation and membrane ultrafiltration

• Isoelectric pH-precipitated fava bean concentrate (FBIEP) had a rigid conformation • FBIEP could be used to formulate food emulsions and lipid containing foods • Fava bean protein concentrate from NaCl extraction (FBUF) had a loose conformation. • FBUF could be used to formulate food foams such as meringues and whipped cream Fava bean (Vicia faba) is gaining attention as a sustainable source of plant protein; however, variations in extraction methods can markedly alter protein structure and, consequently, functional behavior. This study compared two fava bean protein concentrates obtained through isoelectric precipitation (FBIEP) and sodium chloride extraction coupled with membrane ultrafiltration (FBUF) to elucidate how processing-induced conformational changes influence physicochemical and techno-functional properties. FBIEP had significantly (p<0. 05) higher protein yield (61. 87%) and protein content (79. 33%) than FBUF (39. 36% and 62. 75%, respectively). However, FBUF had significantly higher protein solubility (26 – 97%) at pH 5-9 when compared to FBIEP. FBIEP contained significantly higher branched chain amino acids (18. 39%) and essential amino acids (47. 47%) than the FBUF (17. 11% and 46. 58%, respectively). FBIEP also had significant (p<0. 05) higher in vitro protein digestibility (83. 67%) as well as water (2. 25 g/L) and oil (2. 83 g/L) holding capacity than the FBUF (71. 36%, 0. 69 g/L, and 1. 81 g/L, respectively). Far UV-Circular dichroism shows that these protein concentrates primarily exhibit an unordered structure, followed by β-sheets and β-turns, while α-helix conformations are present in the least amount. The mechanistic interpretation suggests that enhanced β-sheet/unordered structures improve hydration and unfolding, whereas α-helix dominance stabilizes interfacial and aggregation behavior. Denaturation temperature was higher for FBIEP (66. 03 °C) when compared to FBUF (55. 20 °C). FBIEP also formed emulsions with smaller oil droplet sizes but had lower foaming capacity than the FBUF. Overall, this study provides molecular-level insight into the structure–function relationships governing fava bean protein performance as a potential food ingredient. By linking secondary structure organization to functional outcomes, these findings establish a rational framework for optimizing pulse protein extraction processes and tailoring ingredient functionalities for specific food applications such as beverages, gels, and emulsions.