Feruloylated arabinoxylan and arabinoxylan-protein solutions do not gel upon γ-irradiation

Solutions of feruloylated water-extractable arabinoxylan (WEAX) and bovine serum albumin (BSA) were γ-irradiated, separately and in admixture, at doses between 0 and 10 kGy, with the objective of gelling by radical mediated inter-chain cross-linking. The effects of γ-irradiation on the macromolecular and structural features of feruloylated WEAX and BSA were investigated. WEAX depolymerized with increasing γ-radiation doses, inducing a sharp decrease in solution viscosity. Concomitantly, monomeric ferulic acid (FA) esters of WEAX disappeared but no FA dimerization was detected. On the contrary, BSA polymerized upon irradiation through disulfide and dityrosine cross-links and also other bonding. This led to a partial insolubilization of the protein with increased irradiation dose. When WEAX and BSA were irradiated in admixture, γ-dose effect was reduced, showing a mutual protection of the macromolecules. No evidence was found that γ-irradiation induced covalent bonding between feruloylated WEAX and BSA.