Effect of freeze-thaw cycles at different temperatures on the properties of gluten proteins in unfermented dough

Background and Objectives The present study investigated the effects of different freezing temperatures and different freeze-thaw cycles on the physical, chemical, functional, and structural properties of gluten protein. The water-holding capacity, rheological properties, water distribution, microstructure, and secondary structure were measured. Findings With the same number of freeze-thaw cycles, the water-holding capacity of gluten was higher at low temperature, and the viscoelasticity and binding water content increased slightly with decreasing temperature. At -30 degrees C and -24 degrees C, the microstructure of gluten protein was more uniform and relatively intact. Lower temperatures significantly decreased the ratio of alpha-helix and beta-turns and significantly increased the ratio of beta-sheets. At the same temperature, the water-holding capacity, bound water content, and viscoelasticity of the freeze-thaw cycle gradually decreased with the increase in the number of freeze-thaw cycles. Compared to the first freeze-thaw cycle (F1), the holes in the microstructure of gluten in the fifth freeze-thaw cycle (F5) were larger and fractured. Conclusions Increasing the number of freeze-thaw cycles damaged the properties of gluten protein, and lower temperatures were more conducive to maintaining the stability of gluten properties. Significance and Novelty This study revealed the changes in gluten protein quality during storage at -6 degrees C, -12 degrees C, -18 degrees C, -24 degrees C, and -30 degrees C and different numbers of freeze-thaw cycles. The results provide a theoretical basis for the quality management and control of frozen dough during storage and transportation.

Automated summary

Lower temperatures are more conducive to maintaining the stability of gluten properties, while increasing the number of freeze-thaw cycles damages the properties of gluten protein.