Faba bean (Vicia faba L.) protein isolates use in colloidal systems and foams: Can ultrasonication and ultrasonication-autoclaving improve the functional properties and morphology?

In this study, we investigated the impact of ultrasonication (US) and ultrasonication-autoclaving (US–AC) on the protein molecular profile, physicochemical, and functional properties of faba bean (Vicia faba L.) protein isolates from two genetically contrasting varieties, Tiffany and Taifun. Ultrasonication markedly increased both the water soluble and salt soluble protein fractions in Taifun, especially the high-molecular-weight globulins as shown by SE-HPLC, whereas the impact on the properties of Tiffany was smaller. SDS-PAGE under reduced conditions revealed that both US and US-AC increased protein aggregation, especially under US-AC in Tiffany. Ultrasonication–AC promoted disulfide-mediated aggregation observed in both varieties. FT-IR revealed that the α-helix-rich Taifun partially unfolded, whereas the rigid, β-sheet-rich Tiffany re-associated upon ultrasonication. Ultrasonication reduced particle size in both Tiffany (136.5 to 66.3 nm) and Taifun (127.5 to 80.2 nm), with lower polydispersity and reduced zeta-potential magnitude (Tiffany −41.1 to −36.0 mV; Taifun −33.1 to −30.3 mV). Foaming capacity increased to 210% in Tiffany and 280% in Taifun, with foam stability of 810 s and 1380 s, respectively. Taifun achieved the highest foaming performance in this study. Ultrasonication is therefore an effective, non-chemical route for tailoring faba bean proteins for aerated foods, but its benefit is strongly variety-dependent and can be reversed by subsequent thermal treatment, showing that varietal selection and processing sequence must be considered together.