Effect of NaHCO_3 and freeze-thaw cycles on frozen dough: From water state, gluten polymerization and microstructure

摘要

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.