Impacts of partial hydrolysis of white bean protein isolate on the physicochemical, interfacial properties, and...

The physicochemical, techno-functional, and antioxidant properties of white bean protein isolate (WBPI) were evaluated after controlled partial enzymatic hydrolysis. WBPI was obtained by alkaline and saline extraction followed by a dialysis process. WBPI and its hydrolysates produced using Alcalase® and Brauzyn® (E:S ratio 1:8, pH 7.0, temperatures of 50 °C and 60 °C, respectively) at different hydrolysis times were characterized regarding modifications in their structural, interfacial, and antioxidant properties. The degree of hydrolysis for Alcalase® and Brauzyn® ranged from 7.0 to 12.9% and from 4.0 to 8.6%, respectively. Enzymatic hydrolysis significantly increased (p < 0.05) the concentration of TCA-soluble peptides to values above 50%, indicating extensive hydrolysis. FTIR and SDS-PAGE analyses revealed structural changes, including an increase in low-molecular-weight bands and rearrangement of secondary structures, associated with protein fragmentation and peptide release. Surface hydrophobicity increased during the first 60 min of hydrolysis (703.64 and 697.05) and subsequently decreased, likely due to molecular rearrangements. Solubility significantly improved, reaching 84.4% at pH 7 and 71.7% at pH 4, exceeding native protein values. Surface tension remained stable (43.97-44.64 mN m^-1), indicating preserved interfacial activity, in contrast to heat-treated WBPI (47.94 mN m^-1). Antioxidant activity after 360 min of hydrolysis reached inhibition values of 57.1% and 68.5% (Alcalase®) and 40.2% and 73.1% (Brauzyn®) in DPPH• and ABTS• + assays, respectively. These results suggest that WBPI hydrolysates are promising ingredients for functional foods, combining enhanced solubility, antioxidant potential, and interfacial stability.