Improving fava bean protein functionality via mild ultrasonication: A comparative study with other plant proteins

Fava bean protein isolate (FBPI) is a promising alternative protein source in food formulation due to its high nutritional value and environmental sustainability. However, its limited solubility and functional properties restrict its use in food applications. This study investigated the effect of mild ultrasonication (72-102 W; 1-15 min) on the structural and functional properties of FBPI and compared it with those of pea, soy, and rice protein isolates. Mild ultrasonication increased FBPI solubility from 40% (untreated) to 92%, particularly after 3-5 min of treatment, which was attributed to the disruption of protein aggregates. In comparison, solubility also increased for pea from 10 to 12% (untreated) to 60-86% for different commercial isolates, soy from control 19% to 36% and rice control 5% to 6% at ultrasonication US 72 W with 5 min treatment. Structural analysis (FTIR and MMS) revealed a high β-sheet content in native FBPI and an increase in β-sheet proportion following mild ultrasonication in all protein isolates, suggesting conformational rearrangements and partial protein unfolding. These molecular changes were accompanied by a marked increase in surface hydrophobicity (H_o), likely due to the exposure of buried hydrophobic residues. The enhanced interfacial properties resulted in a twofold improvement in emulsion stability index, although the emulsifying activity index (EAI) remained relatively unchanged (p > 0.05). Overall, mild ultrasonication induced structural modifications that enhanced the functional performance of FBPI, offering a sustainable approach to improve the quality of plant-based food formulations.