Effect of glutathione on wheat dough properties and bread quality

Reduced glutathione (GSH), released from lysed yeast cells, is well-known for weakening dough structure. However, its influence on bread texture and staling has not yet been completely elucidated. Herein, this study aims at assessing the effects of GSH on dough properties and bread quality, especially bread staling, using Rheofermentometer analysis, texture profile analysis (TPA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and low-field nuclear magnetic resonance (LF-NMR). The results revealed that GSH substantially decreased the dough height and gas-retention capacity during fermentation. The weakened dough structure was attributed to GSH-induced disulfide bond cleavage in gluten proteins and the depolymerization of glutenin polymers. The addition of 0.005%-0.01% GSH resulted in acceptable bread quality. However, bread supplemented with 0.015%-0.03% of GSH exhibited a coarser and more open crumb microstructure, as well as high level of hardness and low resilience during aging. GSH promoted crumb water loss and drove the water shift from the immobilized to the bound state. The DSC and XRD analyses further confirmed that GSH promoted starch retrogradation and recrystallization. These results suggest that apart from the gluten structure, GSH also altered gluten-starch interactions and water redistribution, ultimately decreasing bread quality and accelerating bread staling.