Enhanced pulse protein-proanthocyanidin interactions through electron beam irradiation

Proanthocyanidins (PA) enhance pulse protein networks, but their effectiveness is limited by the globular structure of pulse proteins. Electron beam irradiation (EBI) can modify protein structure, potentially improving protein-PA interactions. This study aimed to determine the effects of EBI (0-10 kGy) on the interactions of soy and pulse (pea, faba and lentil) proteins and PA (25 mg/g protein). Changes in protein solubility, molecular weight (M_W) and thermal stability were evaluated. EBI at 2-5 kGy enhanced protein-PA cross-linking, increasing complex M_W (1.7-5.7X) and decreasing surface hydrophobicity (9-47 %). Faba proteins (highest proline content, 5.66 %) formed the largest urea- and SDS-soluble complexes (581-936 × 10⁴ Da and 208-283 × 10⁴ Da), indicating more extensive interactions with PA, likely due to proline-mediated structural flexibility. Changes in denaturation enthalpy further confirmed that faba proteins had more extensive PA-induced crosslinking via hydrophobic and covalent interactions under EBI. These findings highlight the potential of EBI to enhance pulse protein-PA interactions.