The final established physicochemical properties of steamed bread made from frozen dough: Study of the combined effects of gluten polymerization, water content and starch crystallinity on bread firmness

• Steamed bread made from frozen dough has an increased content of SDS-extractable proteins.
• This is due to lower incorporation of glutenins into gliadins upon steaming.
• Frozen storage induced an increase in starch crystallinity and the bread firmness.
• Starch crystallnity mainly contributed to bread firmness.
• A model was established between SDS-extractable proteins, water content, melting enthalpy of amylopectin and firmness.

The gluten polymerization behavior, water content, starch crystallinity and firmness of Chinese steamed bread made from frozen dough were investigated and their correlations were also established in this study. The decreased degree of gluten polymerization in steamed bread was observed by the enhanced SDS-extractable proteins (SDSEPs) upon frozen storage. Less incorporation of glutenin in the glutenin–gliadin crosslinking of steamed bread mainly contributed to the decreased degree of gluten polymerization. The decreased moisture of steamed bread had a significant negative correlation with the sublimated water in frozen dough (r = −0.8850, P < 0.01). Frozen storage also induced an increase in starch crystallinity and bread firmness. A multiple linear regression model with SDS-extractable proteins, water content and melting enthalpy of starch crystals of steamed bread accounted for 86% of the variance in the natural logarithm of firmness and further revealed that starch crystallinity mainly contributed to bread firmness.