Abstract: In order to investigate the effects of silver carp muscle hydrolysates (SCMHs) on the quality characteristics of frozen dough, the changes in the rheology, microstructure, proofing and baking characteristics of dough with or without 2% of SCMHs after four cycles of freeze-thaw treatment (each consisting of freezing at ?18 ℃ for 18 h and thawing at 4 ℃ for 6 h) were analyzed. Results showed that addition of SCMHs inhibited the increase in the proofing time of frozen-thawed dough and the decrease in the specific volume of the resulting bread, and the most pronounced effect was observed with SCMH at 30 min of hydrolysis (SCMH-30). The proofing time and bread specific volume of the SCMH-30 group were 121 min and 1.72 mL/g compared to 170 min and 1.54 mL/g for the blank control group, respectively, indicating good cryoprotective effect of SCMH-30. Addition of SCMHs decreased the tensile strength but increased the adhesiveness and extensibility of fresh dough, which was likely related to the negative effect of some reducing peptides in SCMHs. Although the tensile strength of dough decreased and the adhesiveness and extensibility increased after four freeze-thaw cycles for all groups, SCMH-30 and trehalose, with good cryoprotective effect, resulted in smaller variations in these parameters. Scanning electron microscopic (SEM) observation indicated that SCMH-30 weakened gluten network formation in dough, but maintained the gluten network structure after four freeze-thaw cycles. The farinographical properties revealed that SCMH-30 significantly decreased dough development and stability time and farinograph quality number (FQN), and increased dough weakness, and this negative effect was ameliorated by addition of glucose oxidase. These findings provide a theoretical guidance for the application of SCMHs to improve the quality of frozen dough.

Key words: frozen dough; silver carp; cryoprotective; specific volume; rheological property