LAUSR

Abstract This study aimed to explore the effectiveness and mechanisms of enhancing the freezing-thawing (F/T) tolerance of frozen dough using e-poly-L-lysine (e-PL) treated industrial yeast. The specific volume, hardness and internal texture changes in steamed bread that added with the e-PL treated yeast after 1–4 times of F/T cycles were investigated. In addition, the growth curves, intracellular trehalose and CO2 production of e-PL treated yeast were further detected. Meanwhile, the protein network of dough was evaluated after F/T cycles. As a result, porous crumb steamed bread with large specific volume and soft texture were obtained in e-PL treated groups (0.1, 0.3 and 0.6 mg/mL) after 4 times of F/T cycles, but the opposite results occurred in the excessive e-PL treated group (0.9 mg/mL) and untreated (0 mg/mL) group. e-PL treated yeast had a longer lag phase and log growth phase, together with higher intracellular trehalose compared with untreated yeast. After F/T cycles, compared with the untreated group, the decrease rates of CO2 production and glutenin macropolymer (GMP) content in e-PL treated groups were lower. Meanwhile, the protein network was more integrity. This study can provide valuable insights into the relationship between e-PL treated yeast and the quality of steamed bread made by frozen dough.