Effect of NaHCO₃ and freeze-thaw cycles on frozen dough: From water state, gluten polymerization and microstructure

This study investigated the influence of NaHCO₃ on the water state, gluten polymerization, microstructure and quality of frozen steamed bread dough during freeze-thaw cycles. Results showed that the steamed bread made from alkaline (0.4% NaHCO₃) frozen dough possessed a larger specific volume and smaller hardness after 4 freeze-thaw cycles, than the non-alkaline dough group. The addition of NaHCO₃ slowed the increase of freezable water content and water mobility of dough during freeze-thaw cycles, and the high amount of NaHCO₃ (0.4%-1%) showed the great effect. Compared with non-alkaline dough, the sodium dodecyl sulfate extractable protein proportion and free sulfhydryl level of alkaline dough increased less after freeze-thaw cycles, indicating a strengthened freeze-thaw tolerance of alkaline dough. Based on microstructure image and corresponding protein network analysis (PNA) results, the protein area and total protein length in alkaline dough remained at a higher level than non-alkaline group after 4 freeze-thaw cycles.