Changes in actomyosin dissociation and endogenous enzyme activities during heating and their relationship with duck meat tenderness

• Shear force of duck meat went down when heating to the temperature of 50–70 °C.
• In the range of 50–70 °C, actin was obvious liberated from actomyosin.
• Actomyosin dissociation and cathepsin D were correlated with meat tenderness.

The objectives of this study, were to examine the relationship between duck meat tenderness, actomyosin dissociation and endogenous enzyme activities when heating the duck breast muscle, to the internal temperature of 30, 40, 50, 60, 70, 80, 90 °C. The shear force increased in the temperature range of 30–50 °C and 70–90 °C and decreased from 50 to 70 °C, which was negatively related with liberated actin (P < 0.05). The activity of cathepsin B and L was stable while heating the meat to a temperature below 50 °C, then it decreased rapidly with temperature increase. The calpain activity kept decreasing with the temperature increase. There was no significant change in the cathepsin D activity below 70 °C but it declined rapidly thereafter, and its activity was strongly correlated with actomyosin dissociation (P < 0.05). The results suggest that actomyosin dissociation and cathepsin D, could contribute to the tenderness of duck meat during the cooking process.