Polymerization of wheat gluten and the changes of glutenin macropolymer (GMP) during the production of Chinese steamed bread

Polymerization of gluten and the changes of glutenin macropolymer (GMP) during the production of Chinese steamed bread (CSB) were investigated, providing a theoretical basis to improve and regulate the quality of CSB. Protein extractability and free sulfhydryl (SH) contents increased to some degree during the dough preparation stage, but significantly (P < 0.05) decreased during steaming. Remarkable protein aggregates were observed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns. The microstructure study of the gas cell and the protein network by confocal laser scanning microscopy (CLSM) further revealed the formation of a continuous and three-dimensional gluten network. The loss and recovery of GMP wet weight during dough processing were significant (P < 0.05). Glutenin depolymerization negatively correlated with GMP wet weight and the contents of high molecular weight glutenin subunits (HMW-GS) and low molecular weight glutenin subunits (LMW-GS). Gluten polymerization led to a decrease in G′ and G″ of GMP while gluten depolymerization induced a slight recovery in G′ and G″ of GMP.