Amyloid-like fibrils accelerate pre-cooked gluten depolymerization during freeze-thaw cycles

This study investigated the impact of amyloid-like fibrils (AFs), derived from thermally processed wheat gluten, on pre-cooked wheat gluten (PCWG) during freeze–thaw (FT) cycles. A systematic analysis was conducted encompassing rheological properties, molecular weight distribution, conformational structure, molecular chain size, and conformation. Key findings demonstrated that the incorporation of AFs exacerbated the reduction in elasticity and viscosity of PCWG under FT treatment. Notably, the tan δ of PCWG containing 1.0 % AFs increased to 1.552 at 1 Hz, indicating an AFs-induced phase transition from a solid-like to a fluid-like state. In addition, AFs competitively establish irreversible covalent cross-links with both glutenin and gliadin subunits, thereby intensifying FT-induced depolymerization of PCWG. Structural analyses revealed that the introduction of 1.0 % AFs reduced the proportions of α-helix and gauche–gauche–gauche disulfide bonds in PCWG after FT treatment to 12.75 % and 22.41 %, respectively. These results indicate that AFs disrupt the hydrogen bonding network and destabilize the stability of disulfide bonds in PCWG. Moreover, the presence of AFs further exacerbated the FT-induced contraction of molecular-chain dimensions; after 10 FT cycles, the radius of gyration of PCWG with 1.0 % AFs decreased to 0.184 nm. Collectively, these findings clarify the mechanism by which AFs exacerbate PCWG depolymerization during FT cycles and offer a theoretical foundation for optimizing the quality of frozen cooked flour-based food systems.