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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 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]