Influence of ε-poly-L-lysine treated yeast on gluten polymerization and freeze-thaw tolerance of frozen dough

摘要

The effects of epsilon-poly-L-lysine (epsilon-PL) treated yeast on gluten polymerization of frozen dough and quality of steamed bread after freeze-thaw cycles were investigated. Compared with steamed bread made from frozen dough containing epsilon-PL and untreated yeast (PUTY) or only untreated yeast, steamed bread made from frozen dough containing epsilon-PL treated yeast (PTY) had a larger specific volume, lower hardness and more porous. A dynamic rheological and scanning electron microscopic analysis demonstrated that using PTY instead of yeast could reduce dough elasticity and damage protein network after freeze-thaw cycles. Lower sodium dodecyl sulfate (SDS) soluble polymeric proteins and monomeric proteins, and higher SDS insoluble proteins were found in frozen dough containing PTY, which indicates a reduced depolymerization of gluten proteins after freeze-thaw cycles. After 4 freeze-thaw cycles, the lower glutathione and free sulfhydryl in dough containing PTY indicate that the interchain disulfide bonds between proteins were preserved.