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The involvement of free and bound lipids on the development of rancidity in wheat–bread dough is studied following frozen storage for 24 months. Lipid oxidation and oxidative stability are determined by assaying peroxide value and thiobarbituric acid reactive substances, which indicate that lipid oxidation starts after three months. High performance liquid chromatography and gas chromatography are used to characterize changes in lipid profile and fatty acid composition, respectively. The bound lipid fraction is mainly composed of polar glycolipids and phospholipids, and their content decreases with storage time because the unsaturated fatty acids in the bound lipid fraction are oxidized. It appears that endogenous wheat lipids, especially the polar lipids with amphiphilic structures and surface activity are most exposed to oxygen because they accumulate at the interface around, and stabilize, the gas cells in the foam structure of the bread. Practical Applications: This study has demonstrated that polar lipids, such as galactolipids, are the most susceptible to oxidation, apparently because they are enriched at the gas bubble interface, where they improve gas bubble stability, but they are also in close contact with oxygen in the gas bubbles. An important practical finding from this study is that lipid oxidation was negligible in the first 3 months of frozen storage (−10 °C) and only became extensive after 6 months. This is important information for the baking industry. [ABSTRACT FROM AUTHOR]

Summary: We have studied the impact of different concentrations of GOX on corn doughs' processing characteristics and protein structure. The doughs were frozen for different periods, and the quality of their products, like corn tortillas, was studied. The results showed that adding GOX attenuated the adverse effects of ice crystals produced during the freezing period and improved the dough's viscoelasticity and low‐temperature stability. In addition, GOX further enhanced its water‐holding capacity, limited water mobility, and re‐established the dough's secondary structure. Furthermore, the results demonstrated that GOX improved the texture and delayed the staling rate of corn tortillas prepared with fresh and frozen corn dough. We further concluded that 100 mg kg−1 of GOX exhibited the best improvement effect on the corn dough characteristics and quality of the produced tortillas. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]