The deterioration law of pre-proofed frozen dough for the southern steamed bread and the improvement mechanism using hydroxypropyl distarch phosphate as the main improvers

This study investigated the deterioration patterns and underlying mechanisms of the pre-proofed frozen dough (PPFD) for the southern steamed bread (PPFD-SSB) during frozen storage, as well as the effects and the action mechanisms of two improvers primarily composed of hydroxypropyl distarch phosphate (HPDP). The southern steamed bread is characterized by its high sugar content. Two different improvers were applied to the PPFD. And the behavior of the moisture and the gluten proteins were evaluated in the fresh, frozen and frozen stored dough (after 7, 14, 21, and 28 days). The results indicated that freezing increased the freezable water content and decreased the bound water content in the dough. The ice crystals formed from freezable water damaged the microstructure of the dough. Frozen also disrupted the gluten protein structure. The HPDP-based improver was able to bind water, which was important to mitigate the accumulation of large ice crystals and reduce the structural damage caused by ice formation. It also improved the fermentation height and the viscoelasticity of the dough. These findings provided theoretical supports for enhancing the quality of the PPFD-SSB and established a basis for developing novel improvers aimed at optimizing the gluten protein structure. • Freezing caused the increase of freezable and free water in the pre-proofed frozen dough for southern steamed bread. • Freezing led to the structure destruction of gluten protein in the pre-proofed frozen dough for southern steamed bread. • HPDP retained the moisture in the pre-proofed frozen dough for southern steamed bread. • HPDP had no obvious effect on gluten protein in the pre-proofed frozen dough for southern steamed bread.