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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]

Factors contributing to the quality deterioration of frozen dough encompass yeast inactivation, gluten network structure disruption, starch crystallinity increment, and ice crystal redistribution. Wheat starch, the primary constituent of dough, comprising approximately 75% of the flour mass fraction, acts a pivotal part in the properties of frozen dough and its final products. This review offers a comprehensive perspective on the mechanisms underlying frozen dough degradation, the physicochemical attributes of various wheat starch types, alterations in the structure and functional profiles of wheat starch during freezing, and correlation between changes in these properties and the decline in frozen dough quality. Significant disparities exist between A-Type and B-Type starch granules, including differences in chemical composition, crystallinity, gel formation, gelatinization, and baking properties. Consequently, the particle sizes of wheat starch may exert varying extent of impact on the degradation of frozen dough. [Display omitted] • The deterioration of frozen dough is mainly attributed to freezing concentration. • Frozen cause damage of yeast, gluten, starch and redistribution of water. • A- and B-Type granules are quite different and their ratio affects dough quality. • The physicochemical properties of B-Type granules were more affected by freezing. • The contribution of A-Type granules to whole wheat starch was more obvious. [ABSTRACT FROM AUTHOR]

The utilization of frozen dough technology presents a compelling solution for prolonging the shelf life of flour products and enhancing production efficiency. This technology has been widely applied and continuously studied. However, the intricate production process of frozen dough introduces a persistent challenge—freezing damage—that impacts different components of frozen dough like starch, gluten protein, yeast, and lipid. This damage leads to a decline in dough quality. This review offers a comprehensive summary of changes occurring in different components in frozen dough from a multiscale perspective, specifically starch, gluten protein, lipid, and yeast. The process improvement methods involving from the main materials to the end products in the actual production process of frozen dough have been discussed. These encompass the selection and optimization of main materials, improvement of yeast freeze tolerance, additives, frozen processes (freezing, storage, and thawing), and dough-making processes. The selection of wheat flour with high gluten strength and the use of composite flour with high dietary fiber can improve the freezing resistance of gluten–starch matrix. The freeze tolerance of yeast can be improved through hybridization, genetic engineering, pretreatment with polycationic peptide (ε-poly- l -lysine), microencapsulation technology, and the addition of anti-freeze agents. In addition to improving the use-effect of different additives, effective methods of obtaining additives and synergistic combinations of multiple additives are in focus. Different frozen doughs need to choose an appropriate freezing rate. The novel physical field-assisted freezing technology has a positive effect on reducing freezing damage. For frozen storage, the subfreezing temperature (−12 °C) is more environmentally friendly and the lower storage temperature is more stable. The innovative microwave thawing has a poor application effect for frozen dough presently. Innovative dough-making processes such as vacuum mixing, heat treatment before dough freezing (part-baked, par-steamed, and preheated dough), and edible coatings are worth exploring. • The quality deterioration mechanism of frozen dough is elucidated with the changes of gluten–starch matrix and other components. • The improvement of the flour and yeast freezing tolerance can improve the quality of frozen dough. • Synergistic combinations of multiple additives can improve the effect of additives. • There is still plenty of room for innovation in frozen dough production such as freezing, storing, thawing and making dough. [ABSTRACT FROM AUTHOR]

Depolymerization of glutenin macropolymers (GMP) widely exists in the frozen dough with little effort in elucidating its effects on steamed bread quality. To clarify this, GMP was fractionated from wheat flour and reconstituted to yeast and chemical leavened dough (YLD/CLD). Results showed that with supplementary GMP fraction, depolymerization degree was alleviated in frozen dough. The bread quality loss from freezing was partially counteracted along with better preserved GMP content. Both of dough elasticity and gas retention capability were enhanced in GMP-enriched frozen dough. Gassing power in frozen YLD decreased while remained constant in CLD. Addition of GMP did not affect the gassing power, which allowed interpreting the improved bread qualities from the enhanced dough elasticity and gas retention capability. Based on the improved facts of frozen steamed bread dough quality with additional GMP fractions, this study revealed the pivotal role of GMP depolymerization on the frozen steamed bread dough quality. [ABSTRACT FROM AUTHOR]

The effects of starch and gluten on the physicochemical properties of frozen dough were studied using reconstituted flour. The profiles of frozen dough were studied by Mixolab, rheometer, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Results revealed that starch, rather than gluten, played a decisive role in mixing properties. The breakdown and aggregation of the gluten network structure as well as the formation of β-turns and β-sheets in the frozen dough would be aggravated by the freezing of wheat starch. Smaller wheat starch granules (B-Type granules) affected the secondary structure of gluten network more than larger granules (A-Type granules), resulting in greater rheological property changes. The viscoelastic properties and freezable water content of frozen dough were more influenced by the freezing of gluten. [Display omitted] • Starch had more impact on mixing characteristics than gluten in frozen dough. • Frozen wheat starch would aggravate the disintegration and aggregation of gluten. • B-Type granules affected the secondary structure of gluten more than A-Type granules. • Gluten played a more important role in the viscoelastic properties of frozen dough. [ABSTRACT FROM AUTHOR]

As an emerging physical technology, magnetic fields have been used to improve the quality of frozen and refrigerated foods. This study compared the effect of applying a static magnetic field (2 mT) at different stages of freezing and storage on the quality of frozen dough. Results suggested that the magnetic field significantly impacted frozen dough quality. It not only prevented the formation of ice crystals during the pre-freezing stage but also inhibited ice crystal growth during the following frozen storage. This effect helped to maintain the integrity of gluten proteins and their adhesion to starch granules by preventing the breakage of disulfide bonds and the depolymerization of gluten macromolecules. It was also observed that yeast inactivation and glutathione release were reduced, resulting in improved air retention and air production capacity of the dough. This, in turn, led to a more appealing volume and texture quality of the finished bread. • Magnetic field (MF) improved volume and texture quality of frozen wheat dough. • MF inhibited ice crystal formation and growth during pre-freezing and frozen storage. • MF prevented disulfide bond breakage and gluten macromolecule depolymerization. • Yeast inactivation and glutathione release were reduced under MF. [ABSTRACT FROM AUTHOR]

This study was to investigate the protective effect of magnetic field (MF) on frozen dough processing quality. The texture, microstructure, rheological and physicochemical properties of wheat dough treated by freezing-thawing cycles under different magnetic flux densities (0, 2, 4, 6, 8, and 10 mT) were analyzed. Compared with conventional frozen dough, MF-treated frozen dough had lower hardness and higher elasticity. Scanning electron microscope exhibited that MF treatment minimized the freezing-induced damages on morphology of starch and gluten, which was consistent with the decreased tan δ in rheological analysis. Application of MF facilitated high relative crystallinity and gelatinization enthalpy in starch granules while the depolymerization of gluten macropolymer was inhibited as manifest with more ordered secondary structure and decreased free sulfhydryl groups. The integrated structure in MF-treated frozen dough resulted in lower free water content as shown by low field nuclear magnetic resonance. The results provided valuable knowledge for the MF-assisted freezing technology and made it possible to improve the freezing-induced deteriorations on wheat-based food. • Wheat dough was frozen/thawed with different magnetic field(MF) intensities. • Freezing-induced damages on starch granule and gluten were repaired by MF. • MF resulted in high starch crystallinity and lower gluten depolymerization. • MF caused a softer hardness and higher elasticity compared with frozen dough. [ABSTRACT FROM AUTHOR]

The present study comparatively evaluated the evolution of yeast and chemical leavened steamed bread dough (YLD/CLD) quality during freeze/thaw (FT) cycles. The steamed bread quality of CLD was more freeze-stable than that of the YLD after 3 FT cycles. Decreased yeast viability contributed to the loss of gassing power in YLD while no significant differences were observed for CLD during FT cycles. However, faster gas release rate in frozen CLD indicated gas retention loss due to the distortion of gluten network. Glutenin macropolymers (GMP) depolymerization via breakage of inter-chain disulfide (SS) bonds and conversions of α-helix and β-turn to β-sheet structures were the main indicators of gluten deterioration. Gluten network was more vulnerable in frozen YLD, resulting in detectable loss of viscoelasticity. The results suggested that supplement of chemical leavener contributed to a more freeze-tolerant gluten network besides its stable gassing power. [ABSTRACT FROM AUTHOR]

The magnetic field is an emerging physical method used for food preservation, characterized by its high penetrability in food materials. The effect of a static magnetic field (MF, 2 mT) on frozen dough upon freeze-thaw treatments (3, 7, and 10 cycles) was investigated, with conventional freeze-thaw (CF) treatments being used as control. Results showed that the magnetic field ensured the baked bread made from dough a 17.59% larger specific volume and a 30.87% smaller crumb hardness. It accelerated the time for the dough to pass through the maximum ice crystal formation zone by 7 min and reduced the ice melting enthalpy from 63.55 J/g to 56.67 J/g after 10 freeze-thaw cycles. Nuclear magnetic resonance analysis suggested that the conversion of bound water to immobilized water and free water was inhibited. The yeast viability and activity were also better maintained, precisely as the observed increase of 18.18% and 42.23% in its survival and gassing power. After 10 freeze-thaw cycles, the free disulfide (SH) content was determined to be 1.642 μmol/g for CF doughs and 1.624 μmol/g for MF ones, respectively. A reduction of 24.26% in glutenin macropolymer depolymerization was achieved, indicated a more stable gluten structure under the magnetic field. [Display omitted] • Magnetic field improved the quality of frozen dough bread. • Lower depolymerization degree was detected in gluten using magnetic field. • Yeast survival and gassing power were better preserved under magnetic field. • Magnetic field inhibited water migrations and status change. [ABSTRACT FROM AUTHOR]

• B-Type granules were more sensitive to freezing than A-Type granules. • The properties of whole wheat starch were close to those of its A-Type granules. • A-Type granule gradually play a leading role in whole wheat starch with frozen time. • The deterioration of B-Type granule had little influence in whole wheat starch. The physicochemical properties of whole wheat starch and its A-Type and B-Type granules isolated from frozen dough at 0, 4 and 8 weeks of storage were investigated. Results showed that profiles of A-Type granules were more or less constant while significant differences of B-Type granules involving in irregular edges, increased relative crystallinities and decreased Viscosities were observed after 8 weeks of storage, suggesting that B-Type granules were more sensitive to freezing. These were mainly attributed to the release of leaching materials from starches, resulting in the ratio of amylose to amylopectin, protein and lipid content decreased by 25.93%, 12.05% and 31.65%, respectively. Whole wheat starch remained essentially unchanged during freezing. It seemed that B-Type granules, as a small part of whole wheat starch, had less influence on whole wheat starch than A-type granules in spite of their significant deterioration upon storage. [ABSTRACT FROM AUTHOR]