Structure–Function Relationships of Ultrasound-Extracted Faba Bean Protein in Stabilizing Oil-in-Water Emulsions

Faba bean protein is emerging as a valuable ingredient in fortified beverages due to its high nutritional quality; however, its functional attributes remain insufficiently understood. This study examined the structure–function relationships of ultrasound-extracted faba bean protein isolate in stabilizing oil-in-water emulsions under different high-pressure homogenization conditions (500 and 1500 bar). Structural analyses showed that ultrasound extracted faba protein retained its secondary structure and exhibited strong thermal stability. Functionally, the extracted faba protein demonstrated high oil-holding capacity and reduced surface tension, supporting enhanced interfacial activity. Emulsion characteristics, including droplet size distribution, rheology, creaming, and gravitational stability, were monitored over 20 days at 4 °C. At 1500 bar, ultrasound-extracted faba protein generated fine emulsions with Dv 50 droplet sizes below 0.4 μm at 1% protein, maintaining long-term stability. Collectively, these results highlight ultrasound extracted faba protein as a promising clean-label emulsifier for next-generation plant-based food formulations.