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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]

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]

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]

Background Gluten proteins are considered as quality determinants in cereal-based food product by forming the backbone structure of dough. Freezing technique has largely expanded the dough shelf life and brought revolutionary development to the bakery industry. However, deterioration of gluten network in frozen dough is one of the major factors leading to the quality loss of bakery products. During the manufacturing process of frozen dough, hydration with optimum mixing is the first and critical step to manage the control dough quality, followed by the freezing and frozen storage to achieve the long time storage of dough, which determines the final dough quality. Scope and approach Series of physicochemical alterations in gluten proteins occur upon the dough formation and frozen storage. Understanding these fundamental changes is important for the research community to propose more rational implementation of specific improvement principals for frozen dough. In this review, the physicochemical alterations of wheat gluten proteins are investigated from the perspectives of gluten and its component glutenin and gliadin. Key findings and conclusions A more structure-ordered, homogeneous and elastic gluten network is formed at the optimum mixing stage as a consequence of glutenin and gliadin interactions. Comparative studies in different model systems demonstrate that further frozen storage exerts detrimental effects on gluten proteins in diverse ways from both gluten proteins-water interactions and structure-functionality perspectives. [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]

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]

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]

Effect of pigskin-originated gelatin on dough properties and bread characteristics, especially on bread staling was investigated in terms of starch retrogradation and water migration in the present study. Results showed that gelatin significantly improved bread qualities during storage. Compared with the control, 7-day staling rate of bread containing 0.5% and 1.0% gelatin decreased by 6.56% and 20.83% respectively, indicating gelatin retarded the staling process of bread. This retardation effect was related to starch retrogradation and water migration. The relative crystallinity decreased from 15.12%, 11.60% to 10.75%, which demonstrated the alleviation effect of amylopectin crystallization. Bread samples containing 1.0% gelatin had the lowest retrogradation enthalpy of 2.93 ± 0.24 J/g followed by 0.5% gelatin bread and the control group, further indicating that gelatin may induce less water available to form crystal lattice and restrict the migration of starch molecules. The 5-day moisture loss rate for the control group was highest with the values of 12.39%, which was 1.43% and 1.83% higher than that of bread with 0.5% gelatin and 1.0% gelatin, respectively. Water activity and T 2 relaxation results provided the information that gelatin inhibited water migration upon storage and gelatin interacted with bread components. However, the effect of gelatin on improving bread quality and retarding staling could not be reflected by the dough properties measured through farinograph, extensograph and rheometer. This study suggested gelatin from pigskin had great potential to be served as an effective bread improver. Image 1 • Gelatin enhanced the bread qualities significantly, especially retarding the staling process. • Gelatin hindered the chain reassociation of starch molecules during storage. • Gelatin interacted with bread components and restricted water transfer. • Dough properties showed gelatin might to some extent weaken the gluten network. [ABSTRACT FROM AUTHOR]

Highlights • The acidified bread showed higher volume, lower moisture content and lower hardness. • Gluten network weakened and yeast activity enhanced in chemical acidified doughs. • Proteins and starches in acidified doughs showed varying degrees of hydrolysis. • Hydrolysis of proteins and starches mainly occurred after dough mixing. • Proteolysis and amylolysis basically depended on types of organic acids. Abstract This study aimed to improve the bread quality by adding acetic acid, lactic acid, malic acid, fumaric acid and citric acid to its ingredients. The underlying mechanism was explored through the changes in the yeast activity, proteolysis and amylolysis. All organic acids gave bread a higher specific volume, a lower moisture content, a lower pH value and a decreased hardness. Moreover, the yeast activity was enhanced, whereas the gas retention capability decreased in acidified doughs. Organic acids also reduced the molecular weight of proteins and starches, which led to the increase of NH 2 , free SH and reducing sugar contents. These changes were the most significant in the dough with 0.3% fumaric acid. Proteolysis and amylolysis mainly occurred after dough mixing and depended on the types of acids present in the mixture. Nevertheless, the cleavage of disulfide bonds in gluten might rest with the H+ concentration in the dough system. [ABSTRACT FROM AUTHOR]

Abstract The aim of this study was to compare effects of linear dextrans (backbones of α-(1 → 6) linkages) varying with weight-average molecular weights (Mw: T10, T70, T250, T750, T2000) on the quality of wheat breads. The firmness of fresh bread crumb was decreased with increasing dextran Mw and the highest Mw dextran (T2000) lowered the staling rate of stored breads. Dough rheology clarified that only the specific dextran (T70) apparently changed dough viscoelastic, strengthening the viscous behavior. Significant decreases in breakdown and setback viscosity of starch slurry were observed by addition of dextrans, especially dextran T2000. Analyses in the long-term retrogradation of starch and starch-gluten systems indicated that the promising antistaling influence of dextran T2000 was caused by either inhibitions of amylopectin retrogradation or beneficial variations induced by gluten. Positive effects of starch-gluten and dextran-gluten associations on amylopectin retrogradation were revealed. These results suggested that the highest Mw dextran (T2000) possessed the potential for increasing consumer acceptance of bread products. Highlights • Dextran T2000 decreased the formation of amylose crystallites. • Dextran T2000 inhibited amylopectin recrystallization. • Retardation of dextrans on the long-term retrogradation of amylopectin was highlighted by gluten. • Starch-gluten and dextran-gluten associations played a powerful role in amylopectin reordering. [ABSTRACT FROM AUTHOR]

Hen egg is commonly used in some cereal-based food, including cakes and bread. Ovalbumin, one of the major components of egg white protein, can affect the performance of the food product. The interaction between ovalbumin and gluten protein and its effect on property of dough and quality of Chinese steamed bread was investigated in this study. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) patterns indicated that ovalbumin was surprisingly not incorporated in glutenins by covalent bond, whereas size-exclusion high-performance liquid chromatography showed that glutenin macropolymer content in glutenins increased slightly. Furthermore, dynamic rheology experiments indicated ovalbumin led to a decrease in G ′ and G″ of dough. Based on molecular dynamic simulation and SDS-PAGE results, it was inferred that ovalbumin was not hydrolyzed by endopeptidases during dough fermentation and crosslinked to gluten proteins during steaming. Finally, ovalbumin improved maximum dough height (Hm) during dough development and specific volume of Chinese steamed bread. [ABSTRACT FROM AUTHOR]

In this study, emulsifiers (sugar ester and sodium stearoyl lactylate), hydrocolloids (guar gum and carboxy methyl cellulose), oxidizers (ascorbic acid and azobisformamide), and enzymes (xylanase and α-amylase) were added into refrigerated dough and revealed their totally different characteristics over 5 days of refrigeration. The optimal refrigerated dough formulation appeared to be the one containing 1% sugar ester, 1% sodium stearoyl lactylate (SSL), 10 mg/kg xylanse and 0.04% ascorbic acid. This optimal formulation predicted a continuous and stable gluten matrix. The secondary structure of refrigerated dough containing optimal formulation remained unchanged while a decrease of 7.00% in α-helix content was observed in control refrigerated dough. It might be ascribed to the enhanced physical intra/intermolecular associations (cross-links or entanglements) of the polymeric chains. These results suggested that the combination of certain additives have a synergistic effect on maintaining the structural characteristics of refrigerated 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]

Abstract: In this study, a glucose oxidase (GOX), papain and xylanase combination was developed for fresh whole wheat dough for both browning inhibition and rheological improvement. Measurements of carotenoids extracted from enzyme-treated doughs showed that 0.001% (w/w) GOX could catalyze the oxidization of 40.0% carotenoids and thus cause a decrease of browning index (BI) by 5.20 during dough preparation. For 24 h browning inhibition, 0.010% (w/w) xylanase and papain individuals were able to separately act on the phenolic compounds and polyphenol oxidase, leading to lower BI rises (5.36 and 7.04, respectively) of doughs as compared to the BI rise (13.53) of the control dough; however, 0.020% GOX caused a higher BI rise (16.60) than control although it made BI decrease by 6.34 at 0 h. Rheological investigations on enzyme-treated doughs revealed that both xylanase and papain led to decreases of elastic (G′) and viscous modulus (G″) of doughs while GOX caused increases of G′ and G″. Therefore, an optimal combination composed of 0.010% (w/w) xylanase, 0.005% (w/w) papain and 0.002% (w/w) GOX was carried out using orthogonal experimental design by comparing BI rises in 24 h, which was also proved as a rheological improver for fresh whole wheat dough. [Copyright &y& Elsevier]

Flavourzyme is a commercial peptidase, mainly with exopeptidase activity. In this study, effects of Flavourzyme addition (0–0.16 g/100 g) on properties of wheat dough and bread were systematically studied. Bread with a low concentration (0.01–0.08 g/100 g) of Flavourzyme addition had a large specific volume and soft texture with a uniform cell structure. The optimal Flavourzyme content was 0.04 g/100 g and the specific volume increased from 3.9 mL/g to 4.4 mL/g, the hardness decreased from 21.7 N to 13.3 N. The gas production capacity of yeast increased with low concentrations of Flavourzyme addition, promoting dough expansion. Flavourzyme had a clear hydrolysis effect on wheat gluten in dough and caused the depolymerization and unfolding of gluten structure, thus decreasing the strength and viscoelasticity of dough. Confocal laser scanning microscopy and scanning electron microscopy results further revealed that a low concentration of Flavourzyme had a slight effect on gluten. However, the gluten structure became discontinuous and open, which made the dough easily collapsed during fermentation, resulting in poor bread quality with high Flavourzyme content. The positive effects of appropriate amount of Flavourzyme addition on dough and bread properties indicated the potential of Flavourzyme as a bread improver by substituting chemical additives. • Moderate amount of Flavourzyme addition improved the quality of bread significantly. • The optimal addition of Flavourzyme is 0.04 g/100 g (based on wheat flour). • Dough expansion was enhanced with moderate Flavourzyme addition. • Moderate Flavourzyme addition did not cause obvious damage to gluten network. [ABSTRACT FROM AUTHOR]

The effect of superheated steam treatment on the physicochemical properties of wheat flour and quality characteristics of cake were investigated. Superheated steam treatment significantly increased the swelling power, viscosities and gelatinization temperature, but reduced the gelatinization enthalpy (p < 0.05), compared with native wheat flour. However, the dough made from the treated flour was harder to form. Moreover, superheated steam treatment significantly increased the value of falling number. Cake quality was affected by the changes in the physicochemical properties of wheat flour. Results showed that superheated steam treatment significantly decreased the hardness of cake from 1465 g (native flour) to 377 g (150 °C, 1 min), and increased the specific volume of cake from 3.12 mL/g (native flour) to 3.9 mL/g (150 °C, 1 min). The present study suggests that superheated steam treatment has great potential as a flour modification technology for cake quality improvement. • Physicochemical properties of wheat flour treated with superheated steam were studied. • Superheated steam treatment weakened the gluten strength of dough. • Superheated steam treatment promoted the functional properties of wheat flour. • Wheat flour superheated steam treatment could improve cake quality characteristics. [ABSTRACT FROM AUTHOR]

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. Image 1 • Glutathione depolymerized protein and weakened gas retention capacity. • Glutathione decreased loaf volume and bread resilience, and increased hardness. • Moisture content decreased and water became less mobile with glutathione. • A coarser porous bread crumb was obtained in the presence of glutathione. • Bread staling rate was significantly increased in the presence of glutathione. [ABSTRACT FROM AUTHOR]

Effect of pigskin gelatin and its hydrolysates on overall changes that frozen dough underwent during storage was investigated. The results showed that gelatin from pigskin could fortified the frozen dough bread quality, embodying in larger bread volume, softer and more uniform bread crumb. Impact of pigskin gelatin on changes in the structure of gluten network in frozen dough was evaluated by different techniques. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) showed gelatin may inhibit the crosslinking of HMW macromolecules and entangle with SDS-soluble LMW proteins. The increased SDS-soluble proteins suggested a lower aggregation extent of glutenin macropolymer (GMP) caused by pigskin gelatin. However, the significant reduction in GMP depolymerization degree and thiol groups (-SH) content after 60-day frozen storage in presence of gelatin indicated the formation of a more resistant gluten structure against the distortion of ice crystals. There were no significant differences in the alteration of secondary structure and high-temperature stability between gelatin-depleted and gelatin-fortified groups. Nevertheless, the effect of pigskin gelatin on qualities of frozen dough was independent on its hydrolysis degree. Image 1 • Gelatin from pigskin fortified the frozen dough bread quality. • Effect of pigskin gelatin on qualities of frozen dough was independent on its hydrolysis degree. • Pigskin gelatin resulted in a lower aggregation extent of glutenin macropolymer. • Gelatin inhibited the crosslinking of HMW macromolecules and entangle with SDS-soluble LMW proteins. [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]