Electron beam-induced structural modification enhances pea protein emulsion gels formed by transglutaminase‑calcium dual crosslinking.

Abstract

Pea protein isolate (PPI) has limited use in the food industry due to its poor solubility and gelation. This study used electron beam irradiation (EBI, 5-30 kGy) to treat PPI, followed by dual crosslinking with transglutaminase (TG) and/or CaCl2 to prepare oil-in-water emulsion gels, aiming to optimize processing conditions for improved gelation properties. Moderate EBI (10-15 kGy, with 15 kGy showing the greatest overall improvement) promoted protein unfolding and increased surface hydrophobicity, water solubility (10.6% → 11.2%), and emulsifying activity index (15.9 → 25.6 m2/g). Dual crosslinking (TG + 25 mM Ca2+) generated stronger, more elastic networks than single crosslinking, with higher water-holding capacity (80.7%), superior freeze-thaw stability, and higher viscoelasticity. EBI-treated PPI produced softer yet more hydrated gels. Excessive Ca2+ (≥50 mM) or irradiation (20-30 kGy) increased protein aggregation and weakened gel strength. This combined physical-enzymatic crosslinking strategy allows tailoring of plant-based emulsion gels for specific food applications.