Glutathione affects rheology and water distribution of wheat dough by changing gluten conformation and protein depolymerisation

Abstract

Summary The effects of reduced glutathione (GSH) on dough rheology, water state and distribution, gluten conformation, and protein molecular weight distribution were investigated. Addition of GSH (0.02−0.04%) resulted in a more viscous and less elastic dough with decreased G ′ and increased tanδ values, which suggested decreased cross‐links in gluten network and a weakened dough structure. The molecular weight of proteins was reduced by the GSH‐induced cleavage of intermolecular disulphide bonds. Fourier transform infrared spectroscopy showed a high fraction of β‐sheet formation at the expense of α‐helix and β‐turns, indicating a destabilised secondary structure and protein depolymerisation. GSH increased water release from the gluten network in dough resulting in an increase in freezable water content and caused water redistributed from bound water to weakly bound water. This study provided insights into correlation between wheat dough rheological properties and gluten structure influenced by GSH.