Unlocking the gelling potential of oat protein: Synergistic effects of sonication and disulfide cleavage

The high thermal stability of oat globulin, attributed to inter-subunit disulfide bonds and strong hydrophobic interactions, poses a challenge to its gelling capacity. This study investigated the heat-induced gelling properties of oat protein isolate (OPI), focusing on the synergistic effect of physical (high-intensity ultrasound, HIU) and chemical (cysteine-assisted disulfide bond disruption) treatments. Creep-recovery and viscoelasticity (Gʹ/Gʹʹ) tests revealed decreased deformability and enhanced rigidity of OPI intermolecular structure upon cysteine treatment (100–400 mg/g protein), especially for HIU-treated protein. The HIU + cysteine process substantially increased the gel hardness (from 0.005 to 0.69 N) over the individual treatments with a synergy up to 432%. Correspondingly, cooking loss was reduced by 28–98% due to the move of free water into a restricted state (protein-bound protons) within the gel matrix as detected by ¹H NMR. These findings suggest new possibilities for utilizing oat protein in gel-based food products.