Effects of catechins on the polymerisation behaviour, conformation and viscoelasticity of wheat gluten
Junxian Pan, Haihua Zhang, Jun Liu, Yulan Jiang, Yangjun Lv, Jianzhong Han
Abstract
Summary The effects of catechins on the structural properties of wheat gluten were investigated in terms of their polymerisation behaviour, conformation and viscoelasticity. Depolymerisation of glutenin macropolymers was analysed by size‐exclusion high‐performance liquid chromatography (SE‐HPLC) of gluten with catechins, revealing major variation in sulfhydryl (SH) content. Compared with controls, the SH content of catechin‐enhanced gluten was significantly increased due to breakage of disulphide (SS) bonds. Reversed‐phase HPLC revealed that catechins had minimal effect on subunit distribution of gliadin and glutenin. Fourier transform infrared (FTIR) spectroscopy showed that catechins induced the transformation of α‐helices to β‐sheets, β‐turns and antiparallel β‐sheets. Rearrangement of secondary structure when supplemented with catechins might be a consequence of altered non‐covalent interactions. Catechins increased tan δ, indicating enhanced gluten fluid properties. These results imply that catechins might weaken the network structure of gluten and change the rheological properties by inhibiting SS cross‐linkage formation and influencing non‐covalent bonds.