Frozen dough technology has widely been used beyond family bread production at present. The procedures of dough making and baking have therefore been separated to effectively extend the shelf life of bread, while free of starch aging to ensure the freshness for the convenience of transport and consumption of dough products. Therefore, the technology has been rapidly developed to promote the chain operation of the baking industry in the world. Meanwhile, it is necessary to explore the efficient improvement in response to the frozen dough being easy to deteriorate, due to the formation of ice crystals under freezing storage. This study aims to systematically review the degradation mechanism of frozen dough from the following aspects: the yeast activity and gas production, the changes of key components (such as gluten protein, water distribution, and damaged starch), the microstructure of gluten protein, as well as the rheological properties of frozen dough. The improvement of frozen dough was covered ranging from the freezing technology, the screening of antifreeze yeast, together with the addition of enzyme preparation, antifreeze agents, and emulsifiers. In freezing, the yeast activity and gas production decreased, resulting from the changes in the cell membrane of yeast. The screening of antifreeze yeast effectively strengthened the activity of yeast for a higher quality of frozen dough. Nevertheless, the structure of gluten protein was deteriorated, due to the formation of ice crystals. Specifically, the content of glutenin macromolecular polymer was significantly reduced, and the content of soluble protein increased. The elasticity and hardness of dough relied mainly on the depolymerization of glutenin macromolecular polymer, further on the break of the disulfide bond. Non-covalent bond was also involved in the polymerization of gluten protein. The surface hydrophobicity of gluten protein increased during the frozen storage, where the aggregation state of gluten protein molecular was destroyed to rearrange the gluten protein structure with the exposure of hydrophobic sites. In frozen storage, the secondary structure in gluten protein also changed significantly to damage the whole structure, where there were some changes in the content of α-helix and β-sheet orderly structure, while an increase in the anti-parallel β-sheet, and β-turns disorderly structure. As such, the enzyme preparations were used to enhance the structure of gluten protein. The water in the frozen dough was redistributed due to the recrystallization of ice crystals, where the spatial conformation rearrangement of gluten protein was caused by the change of disulfide and non-covalent bond. Thus, the interaction between tightly bound water and gluten protein was weakened, and the water holding capacity of gluten protein decreased. Correspondingly, food gums and antifreeze agents were added to prevent the formation of large ice crystals caused by water migration. Damaged starch transferred the water in gluten protein, and further weakened the interaction between starch granules and gluten protein, indicating an adverse influence on the gluten structure and processing characteristics of dough. The modified starch was generally added to enhance the water holding of dough for the better quality of frozen dough. These approaches contributed to preventing the deterioration of gluten structure, while enhancing the viscoelastic properties of frozen dough. The emulsifier was used to reduce water migration resistance to starch aging. The improvement of freezing technology was a benefit to the antifreeze effect of dough and the less sensitivity of yeast. This review can provide a promising theoretical basis and practical reference to inhibit the quality deterioration of frozen dough. The efficient improvement technology was also evaluated from three key factors, including the fermentation characteristics, the structure of gluten, and the state of water. © 2021, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.
